Servicing The Mazda Miata MX-5

This page describes all the issues I found on my MX-5 and how I intend to resolve them. The good news is that the MX-5 is a very simple car (no fancy electronics) and most parts are still readily available. There are also several service manuals available for this car.

Scheduled Maintenance for 2008

Initial Issues

Problems that came with the car.

Date Severity Status Description
10 Feb 2007 Low Dormant Passenger-side window is squeaky.

After opening and closing the window a few more times, the rubber came up and Mike had to help me dismantle the door frame to push the rubber back. It worked for about a week, then I realized the rubber started to come up again.

Decided not to wind down the window anymore. But that's impossible when you have a passenger. Finally, a colleague wanted to borrow the car for a wedding shot and I opened up the door frame to push the rubber back. This worked for another week.

[Apr 2007] Finally, to solve this problem for once and for all, I opened the door frame once more and superglued the rubber to its metal holder. Hopefully this will stick.

Even so, now I guide the window along when I close it to prevent the rubber from coming out. May need to superglue the top part as well.

10 Feb 2007 Low Passenger-side door requires additional strength to close properly. (Even so, you don't have to slam it!)

It really depends how you close the door. It's annoying, but not annoying enough to look into it yet.

[Jun 2007] The driver side door also shows the symptom now. Sometimes it takes 3 to 5 tries to close the door properly. To look at the door mechanism.

10 Feb 2007 Low Dormant Bumper is misaligned. The gap is slightly bigger on the left side. First thought was to check for accident.

No action intended for now. When I'm free, I'll see if I can realign it myself.

10 Feb 2007 Very low Closed Non-stock rims. Having the stock rims (in good condition) would show the previous owner(s) care about the resale value.

Originally, I wanted to look for the original rims. However, they are size 14 and the current rims are size 16. I think size 14 would look too small. The current rims are not really very nice, but I won't change them unless they turned out to be too heavy. I'm not after aesthetics, but fuel efficiency.

10 Feb 2007 Very low Non-stock steering wheel. A small part has torned off and another part has come unwrapped.

[Sep 2007] Attempted to superglue the unwrapped part. Doesn't work.

Works just as well. No action intended for now.

10 Feb 2007 Very low Closed Faded seat belt buckles. For an owner who seems to take good care of the car, it seems strange to me he didn't change them to new ones.

[May 2007] Getting a new set. This is the first giveaway that the car is old. The interior is grade A otherwise.

[Jan 2008] Finally replaced the seat belt buckles.

10 Feb 2007 Very low Closed No toolbag. I suppose the car should come with a simple toolbag. Again, this indicates how the previous owner(s) take care of the car and its parts.

Apparently the MX-5 doesn't come with a toolbag. No big deal. I got myself a standard set of wrenches, sockets and other tools.

22 Feb 2007 Very low Dormant Glove box doesn't close fully.

No action intended for now. Will try to realign it myself.

22 Feb 2007 Low Left mirror is partially non-reflective.

[Apr 2007] Getting a new set of mirrors.

[Jul 2007] Got the new mirrors, but haven't got around installing them yet. One reason is that the colors are slightly different. The other is that I'll actually miss the blindspot mirror when parking.

[Feb 2008] Tried to replace the mirror, but the new mirror had an extra key that need to be filed away.

[Feb 2008] I rubbed the old left side mirror with alcohol to remove the glue. Worked to a certain extent.

22 Feb 2007 Low Dormant Brakes seem slightly soft.

They still work very well. No action intended for now.

22 Feb 2007 Medium Dormant Can be quite hard to shift into gear, especially the second gear.

Not so bad once you're used to it. It's tough when the car just starts up, but it's easier to shift after a short drive. May need to change the transmission oil.

[Jun 2007] The shift works much better after the shift stick bushings are changed. It still grinds sometimes when shifting into the second gear, though. This could be gearbox related.

22 Feb 2007 Very low Dormant Spots on the dashboard.

No action intended for now.

22 Feb 2007 Very low Closed Non-original keys.

[Mar 2007] Got a new set from Mazda. No difference except for the Mazda logo.

22 Feb 2007 Very low Closed Incorrect owner's manual. I was passed a photocopied owner's manual for a UK 1.8L model. I consider this to be very good already, but having the original one (in Japanese) would be icing on the cake.

[Mar 2007] Got one US '91 manual from eBay.

22 Feb 2007 Medium The car steers towards the left.

[Mar 2007] Went for wheel alignment with the recommended camber/caster/toe settings. Doesn't steer so obviously now, but there is still bumper steer — car steers to the left on an uneven road surface.

23 Feb 2007 Very low Dormant Broken catch for the center console.

This makes it easier to open the center console. No action intended for now.

[Jun 2007] The console is warpped, the latch in the cover doesn't reach the console. Still no action intended for now.

23 Feb 2007 Very low Closed Rattling from something inside the glove box.

Doesn't rattle when passenger is present. No action intended for now.

[May 2007] It rattles very rarely now. Maybe it has to do with the glove box contents.

[Jul 2007] I just realized the rattling comes from behind the glove box. To investigate further.

[Aug 2007] Doesn't seem to rattle after the mechanic opened it up to replace the air-con evaporator. To monitor.

[Oct 2007] Doesn't rattle now.

23 Feb 2007 Very low Closed Rattling somewhere around the IU.

Doesn't rattle when passenger is present. No action intended for now.

[May 2007] Don't hear the rattling anymore.

[Jun 2007] The rattling comes from the IU. It goes away when I press the IU firmly against its holder.

23 Feb 2007 Very low Closed Rattling from the soft-top.

Doesn't rattle when passenger is present. No action intended for now.

[Apr 2007] I realized it doesn't rattle when it's closed properly (close soft-top before the window).

23 Feb 2007 Low Closed Parking lights are not working.

[Feb 2007] Replaced with new set.

23 Feb 2007 Low Closed High beam is not working (no light).

Intend to troubleshoot once I find time. There are 3 wire connections and one fuse box to check.

[Jun 2007] Tested the wire connection on the right headlight. It had no voltage on high beam. Now I need to check the connections below the dashboard.

[15 Jul 2007] Discovered the high beam wire was disconnected in the combination switch. Connected it back and the high beam worked! However, it can be toggled very easily — the light switch stalk is somewhat loose. So this is why the previous mechanic disconnected it.

The high beam indicator on the dashboard was working, but it had hairlight cracks and the backlight was showing through.

[25 Jul 2007] Removed the high beam connector to prevent accidential high beam. To dismantle the combination switch to see how to reduce the play in the light switch stalk.

[19 Feb 2008] Changed the combination switch. Reconnected the high beam connector.

23 Feb 2007 Low Closed One of the headlights' aim is out.

[Mar 2007] Adjusted.

23 Feb 2007 Low Closed The headlights are very dim and totally useless at night. Either the bulbs are weak or that's by design. May change the bulbs.

[19 Feb 2008] I finally managed to unlatch the bulb's retaining clip and remove the bulb from the headlight. I was surprised to see it enclosed in a blue cover! I suspect it's to give white light from a yellow bulb. No wonder it's so dim!

[20 Feb 2008] Removed the blue cover from both bulbs. Washed the headlights too. They are now much brighter! Realigned the headlights to shine further too.

23 Feb 2007 Medium Closed Something is leaking from the engine.

[Mar 2007] Power steering hose was leaking. Replaced by mechanic (~$300).

23 Feb 2007 Medium Closed The car vibrates periodically during idle when shifted into a gear, but only if the air-con is off (when the air-con is on, the idle rpm is higher and it dips lesser).

[Mar 2007] The mechanic adjusted the idle speed to be higher. Interestingly, after I cleaned the air filter and the spark plugs, the problem came back. Will adjust it myself soon.

[May 2007] Adjusted the idle speed so that it is around 850 rpm after warm up. The idle speed is perfect when the air-con is off. When the air-con is on, the idle will droop periodically due to the air-con turning on and off.

23 Feb 2007 High Dormant The car seems to "slip" for a split second sometimes. It is most noticeable when you let go of the accelerator in high gear above 70 km/h. Happens 1/5th of the time.

Still under observation. May be gearbox related.

[Sep 2007] Haven't observed this for a long time. May be transmission fluid related.

23 Feb 2007 High Closed Shift stick vibrates excessively in third gear at around 2k rpm when you let go of the accelerator.

Gearbox related.

[Jul 2007] The vibration is no longer present after replacing the broken shift stick bushings.

23 Feb 2007 High Can have grinding sound when shifting from fourth gear to third above 40 km/h.

Gearbox related. Highly suspect only the third gear synchromesh is worn out, but the workshop recommended changing the whole gearbox (~$900). Putting it off. Solution in the mean time is to blip the throttle when going from fourth to third gear.

If the gearbox is replaced, I'll tell the mechanic to look at the clutch plates and flywheel. Most likely they need to be replaced as well.

26 Feb 2007 Very low Closed Soft-top is misaligned when closed. There's a gap on the passenger side.

Depends how you close the top. I realized there is no gap if I close the top before winding up the windows.

26 Feb 2007 Low Closed Passenger-side window doesn't flush fully with the rubber seals. Possible to leak in heavy rain.

There is no gap if I close the top before winding up the window. Anyway, there's very minor leak in the heaviest thunderstorm.

Mar 2007 Medium The car appears to be tilting to the right (when viewed from the back). The suspensions could be uneven. The front left body is 62 cm from the ground, front right is 61 cm. The rear left is 64 cm and the rear right is 63.5 cm.

This could be why there is bumper steer. Will try to measure the tilt degree and see what needs to be done to correct it. May need to adjust or change the suspensions.

[May 2007] The uneven ride height may not be due to the suspensions. When I jack up the front of the car, the left side is still higher than the right side.

[Jul 2007] I checked out another NA and it had the same tilting problem! This could be within factory specs.

[Feb 2008] According to an online post, this could be due to slipped bushing after prolonged use.

Mar 2007 Low You can hear some faint groaning from the rear during u-turns. Similar or the same sound can be heard if the car is crawling along on the fourth gear.

Suspect this is due to lack of lubriciant. Need to find out what joints to lubricate.

Mar 2007 Low Closed The turn signal turns off easily when the steering wheel is still being shifted. This is pretty irritating if you like to keep the signal on until the turn is completed. I suspect the mechanical catch is giving way.

[Jul 2007] Bought a new combination switch, but haven't got around installing it.

[19 Feb 2008] Changed the combination switch. It doesn't help with the turn signals.

New problems

These problems started only after I took delivery of the car.

Date Severity Status Description
May 2007 Medium Some strange periodic ticking/knocking sound on a full left or right turn.

I only observed this some time after I rotated the tyres, but they may not be linked.

[Jun 2007] The sound comes from the front right wheel, once per revolution. Will jack up the car and turn it manually to identify the source.

[24 Jul 2007] I jacked up the front of the car and spinned the right wheel myself. No knocking sound. Need to find another way to reproduce the sound.

[19 Aug 2007] I managed to find the cause by moving the car to-and-fro at the point where it knocked. It happened when the front right wheel hit the brake line.

[23 Aug 2007] Swapped front and rear right tyres. The original front tyres rubbed against the brake line on a full right turn all the time, but there's no knocking sound!

10 Jul 2007 Medium Closed Clutch fluid leaking from the flexible clutch hose behind the engine. It's leaking on both ends!

This could be an old problem, but I don't remember seeing it before.

[Jul 2007] The fluid did not reappear after a few days of observation. To continue to keep under observation.

[23 Jul 2007] Saw the fluid again. It was a slow leak and had form only a small puddle since my last inspection 4 days ago. Still, it need to be fixed.

[20 Aug 2007] Sent to mechanic to replace. $45 for labour and $10 to bleed the fluid, GST $3.85.

Jul 2007 Low Dormant Rain accumulates on the lower right of the rear windscreen. The seal will leak sooner or later and then water will seep into the cabin. No action intended for now except to dry it as soon as possible after each rain.

[Oct 2007] Sometimes the rain accumulates on the lower left. It depends how level the road is.

27 Jul 2007 Medium Discovered water in the boot, on the battery side. I already saw this once before, but I attributed that to opening the boot in heavy rain because it did not come back in subsequent rains. However, now I found water again. The insulation did not seem to be wet, just the uncovered parts. To monitor.

[28 Aug 2007] Discovered water again after a downpour of 5 hours.

[29 Aug 2007] Ripped out the entire insulation to find the source of the leak faster. The insulation absorbs the water and makes it hard to find the source.

[3 Sep 2007] Found water in two area: one near the battery and the other near the fuel pipe. The one near the battery seems to be leaking from the rubber seal. I can't find the point of the leak on the other side. Will do further tests to isolate it.

[10 Sep 2007] Thanks to the daily rain, I have isolated the source of the leak. The water leaks through a metal welding joint point on the right side of the boot. There seems to be no leak on the other side.

28 Jul 2007 Low Closed The engine oil drain plug leaked after I did my oil change. It continues to leak even after I have tightened it the last time. To tighten it again.

The engine oil also seems to be leaking from another place. I need to clean the underside so that I can confirm the source of the leak.

[19 Aug 2007] Tightened the drain plug once again.

[10 Sep 2007] Doesn't observe oil stains on the ground anymore.

10 Aug 2007 Medium Closed The air-con no longer feels cold. I first noticed this after I changed the air filter, but I thought I did not turn it on long enough.

Now, I observe two more symptoms:

  • Idle goes up to 1.5k rpm when in gear
  • No condensation on the ground after stopping

[20 Aug 2007] Sent to mechanic to diagnose. Claimed the air-con evaporator coil was spoilt. Replaced this ($270) and valve ($45), labour $80, GST $27.65.

14 Aug 2007 Medium I smelled petrol fumes in the cabin. This was the second time I smelled this. This only happens if the car is left untouched for two to three days. I have also smelled petrol fumes in the boot a few times. This happened if I left the car alone for one whole day.

I hope this is not an actual leak but the residue leaked petrol from the time I changed the fuel filter.

[19 Aug 2007] The petrol fumes originate from the left side of the boot. There is no smell on the right side nor in the cabin. This is after two days of leaving the car alone.

[3 Sep 2007] Interestingly, the smell seems to be more faint with a full tank.

[19 Sep 2007] The petrol fumes is still present, but remains quite faint even as the level goes down. This could be valve or charcoal canister related.

[Feb 2008] I got two new fuel hoses, but it'll take a while before I get around to replace them.

19 Aug 2007 Medium The car locking system now doesn't respond. This started happening from two weeks back. Initially, I had to press the lock buttom multiple times before the car would lock. Then from a few days ago, even unlocking doesn't work. I tried the second alarm and it was worse — there was no response at all!

The alarm device is very fragile. It didn't auto-lock the car once I touched it slightly. Recently, I had to fiddle with it to get to the fuel pump relay. I suspect that's when my problems started.

[27 Aug 2007] Took out the alarm and now I locked the car doors manually. I need to remember to lock both sides!

28 Aug 2007 Low Closed [28 Aug 2007] When driving after a downpour of 5 hours, I heard water sloshing on the left side when I applied brakes. Didn't hear it after 5 minutes of driving.

[3 Sep 2007] Cleared the 8 drain holes after a prolong downpour. 4 on the right side were clear. One each on the front and back on the left side were totally blocked. The other two were somewhat blocked and water leaked out after I cleared them with a paper clip.

[10 Sep 2007] Both drain holes on the left back are now clear. One on the front left is still blocked. No water sloshing sound.


In a month, I went from totally car illterate to knowing how a car works, owning a set of tools and being ready to do simple maintenance. The challenge is to actually do it. When physical labour is involved, it's never easy to find the time and space.

Someone asked me if I wanted to save money by doing my own maintenance. That's not my intention. It takes time and effort to hunt down the parts and to do the maintenance. And things can go wrong. I do it because I find it interesting to know how well the car has been working and why.

I started with the simplest maintenance and slowly build up my experience with the car. Each servicing is a learning exercise. I started with a set of 1/4" and 3/8" (mixed) socket wrenches and a dual side flat/philip screw driver.

Note that this is not the full maintenance record.

Date Mileage Description
6 Apr 2007 Cleaned the air filter.

Tools required: 10 mm wrench, 10 mm socket wrench and 16 mm wrench.

The 16 mm wrench is to remove the strut bar. The strut bar is optional, so not all MX-5 have it. In general, most work under the engine hood requires the strut bar to be removed.

It is possible to use a screw driver to remove the air filter screws, but I didn't have the correct size. Without a screw driver, it is necessary to have both a wrench and socket wrench due to the clearance.

The air filter is pretty dirty and while I think it still works fine, I'll just change it for ease of mind (on order). After that, I'll inspect it every 10k km and change it if necessary.

This is a leisurely 5-minutes job.

7 Apr 2007 Cleaned the spark plugs.

Tools required: 16 mm spark plug wrench, socket extension.

It took me three attempts to remove the spark plugs.

First attempt: took hell of a long time to remove the spark plug leads. Everything requires a lot of strength! Discovered the spark plugs were buried deep inside the engine and I needed a socket extension.

Second attempt: bought a t-bar spark plug removal tool. It didn't have enough leverage to turn the spark plugs. I bought this t-bar tool because it had a removable 16 mm and 21 mm socket. Oh well, I can still use it on my motorbikes.

Third attempt: bought an entire 1/2" socket wrench set to get an extension socket. Not really, I wanted a set of 1/2" drive socket wrench. Bought a magnetic 16 mm spark plug removal wrench too. Finally managed to remove the spark plugs and clean them.

This is a leisurely 10-minutes job if done right. Make sure the engine is either cold or warm and not hot!

The spark plugs were due for a change in March. The current ones are coated with carbon, so something isn't right. I intend to find the cause before I replaced them. Otherwise the new spark plugs will still be fouled with carbon after a while.

The previous owner told me the car felt more powerful after the spark plugs were changed. So clean spark plugs make a difference. But why are they coated with carbon and are a little rusted? I need to blow the rust out from one of the cylinders as well. Need to find a air gun first.

I also believe the spark plug leads are still working fine, but I may get a new set all the same. The spark plug leads are supposed to be replaced every 60,000 km.

[May 2007] I inspected two of the spark plugs and they are not fouled with carbon, so I believe the cause of the fouling is no longer present.

12 May 2007 238,838 Rotated tyres.

Tools required: cross bar with 21 mm thin socket wrench, car jack, 4 jack stands and lots of strength!

Very important note: loosen the nuts before jacking up the car!

Took an hour. Totally exhausted. Good practice using the jack stands. It was harder to jack up the car than I expected. It costs just $20 to rotate the tyres outside, with balancing thrown in. So it doesn't look like it's worth the effort to DIY.

I didn't have a torque wrench, so I tightened by feel. I checked the nuts were still tight after every few rides.

28 May 2007 239,155 Changed engine oil. The "test". If I can handle this, I can do other maintenance not described in the owner's manual. The oil change was due in March.

Tools required: 19 mm wrench, 68 cm / 14 oil filter wrench, socket extension, car jack, 4 jack stands, drain pan, cup, funnel and lots of newspaper.

This should take about an hour, including jacking up the car. It took me 1-1/2 days cos I couldn't remove the oil filter by hand and had to wait until the next day to buy a oil filter wrench!

I drove round my estate (6 km in 5 minutes) to warm up the oil. The engine was very hot and I had to wait a while for it to cool down. I was conservative because I didn't know how long it takes for the oil to warm up. Next time I'll travel just 2 km.

It may be possible to unscrew the drain plug without jacking the car up.

I couldn't remove the oil filter by hand. It was way too tight! A oil filter wrench is a must.

I couldn't pour the engine oil out of the can into the engine directly. It leaked all over the place. It may be doable for a bottle.

28 May 2007 239,157 Cleaned the exhaust pipe.

Tools required: tissue paper, degreaser and soap to wash the hands afterwards.

29 May 2007 239,171 Adjusted idle RPM to 850 RPM. This got rid of the idle droop.

Tools required: flat head screw driver, metal paper clip to short the TEN and GND connectors.

7 Jun 2007 239,283 Changed the PCV valve. Supposed to remove it for inspection only, but broke it. It was too tight and the gasket had harden.

Tools required: by right none are needed. Test the gasket and rubber hose first. If they are hardened, then most likely it is impossible to remove the valve without breaking/replacing something.

9 Jun 2007 239,313 It is slightly harder to change the transmission oil than the engine oil. May will leave this to the workshop as it may not be easy to fill up the transmission oil if a pump is needed.

Tools required: car jack, 4 jack stands, 14 mm and 24 mm wrenches, drain pan, pump and some sort of mat.

[Jun 2007] Am just able to squeeze under the car with the default jack stand height, so saved a little effort on multi-stage jacking. The mat is to allow you to slide beneath the car without getting yourself dirty. A hammer may be necessary to force open over-tightened plugs.

As with the engine oil, I drove around my estate (6 km) to warm up the transmission oil.

Good tip to open the fill plug first. I almost couldn't open it. Another tip: the oil may drain from the fill plug. I wasn't prepared for that and quite a bit of oil was spilled on the ground before I could put the drain pan underneath.

The magentic drain plug had sludge and tiny metal pieces. The oil looked dirty, but it was still somewhat translucent.

A pump is absolutely necessary. There is very little clearance to fit any bottles. Only a small 150mm bottle can go in. I waited for the exhaust to cool down before I started work, cos it's too easy to touch something by mistake.

The car wasn't level, so I could only put in 1.875 quarts before the oil spilled out from the fill plug. Next time I need to jack up the front of the car more.

10 Jun 2007 239,313 The differential oil needs to be changed as well. It uses the transmission oil.

Tools required: 23 mm and 24 mm wrenches, drain pan, pump and mat.

It is not necessary to jack up the car. The pump is optional. A bottle will do.

A hammer may be necessary to force open over-tightened plugs. I didn't have a 23mm wrench at first, so I hammered using a 24mm wrench. All it did was round the edges. I then bought a 23mm wrench and the plug finally gave way after a few minutes of hammering — I thought it wasn't going to work.

Same tips apply: open the fill plug first, and oil may spill from it.

The oil looked very sluggish and dirty. The magnetic drain plug had one thick layer of sludge. No metal pieces. I doubt the oil was ever changed.

I only managed to put in 0.55 quarts of oil. The car was on the ground.

11 Jun 2007 239,320 I want to get the current ECU fault codes.

Tools required: metal paper clip, LED.

I got code 18, or was it 8? I will reset the code and see if the error still exist.

[23 Jun 2007] The error did not come back.

[23 Jul 2007] Still no error code.

21 Jun 2007 Removed the fixed antenna to make it easier to cover the whole car.

Tools required: 10mm open spanner.

23 Jun 2007 239,551 I suspect the shifter boots are torn because one of the symptoms is a hot cabin. I may change the shift turret oil as well. It uses the transmission oil.

Tools required: philips screwdriver, 10mm spanner, syringe and pen knife.

Note that a socket wrench will not fit due to space constraints. A pen knife is needed to cut the old inner boot cover due to the "one-way valve" design of the shift stick. A 5ml syringe is needed to suck out all the old oil; a 10ml syringe just barely fit.

As I expected, both boot covers were torn. There are two boot covers — inner and outer — although it isn't obvious from most articles how the inner one looks like. There was a thick layer of padding above the outer boot cover. I suspect that was a quick fix by an earlier owner (more likely, his workshop) to eliminate the heat. Well, it didn't work. The padding below the outer boot cover was absent.

Surprisingly, there were still remnants of turret oil — about 39ml. It looked very sluggish and dirty, just like the differential oil. It must have not been changed in a long time.

There were many plastic fragments that took me quite a while to fish out.

I put in 90ml of oil, and it reached just the gear lever. It did not even fill half of the available space. It was impossible to slide both boot covers down the shift stick until I put a bit of oil on the rubber.

There are three things to watch out for.

Once the inner boot cover is past the shift stick, there is a second notch for it to go past. If you don't go past this notch, the rubber is stretched and subjected to a lot more flexing during gear shifting. Try shifting at this point to see the effect.

Then, you'll notice a space between the inner boot cover and the shift stick. That's where you put in the heat insulation pad. It looks too big to fit in-between the two boot covers, but it'll fit fine if you stuff the pad into the gap between the inner boot cover and the car body.

(It turned out that the thick padding I saw above the outer boot cover was this pad. Some previous mechanic must have put it on top instead of below because he couldn't figure how it fit. It was stretched, that's why I didn't recognize it at first.)

It is also necessary to slide the outer boot cover all the way down. Again, if you don't do so, it'll be subjected to more flexing.

Despite all my precautions, I overlooked the o-ring that was supposed to be put before the inner boot cover. After some mulling, I decided to cut the inner boot cover to put back the o-ring. I also got two new bushings (the gear lever bushing and sheet spring) to replace the broken ones.

26 Jun 2007 Charged the battery.

Tools required: 10mm wrench.

It is necessary to move the battery out to unscrew the negative terminal.

The battery measured 12.48V immediately after driving, and 12.38V about two hours later. It measured 12.2V previously when I tested it.

The battery is dated 10/2005. I don't know how to interpret the indicator on top of the battery. It either says the battery is still very good or that it needs to be recharged.

After charging, the battery measured 12.78V in the car.

[Jul 2007] I did not tighten the positive terminal properly and the cable came off easily. I tested connecting and disconnecting it. No sparks. I'll leave it as-is for now as it makes it easy to disconnect the battery when necessary. I must be extremely careful when removing the positive terminal, though — must wrap it with a piece of cloth to avoid it coming into contact with any metal surface.

1 Jul 2007 239,617 The coolant looks dirty green. It's time to change it.

Tools required: philips screwdriver, drain pan, pump.

I cleaned the coolant reservoir first. You need a pump to remove the coolant. The coolant was dirty green, had particles and somewhat oily. The plastic container was full of sludge. I flushed it 3 times with tap water and once with distilled water. It took 200ml to reach the empty mark and another 300ml to reach the full mark. I was not able to clean it properly. I'm going to remove it and give it a good cleaning one day.

The drain pan should be sufficient for up to 4 litres. The engine holds 6 litres of coolant, but only 4 litres will be drained out. There is no need to jack up the car to remove the drain plug. You will get coolant dripping on your hand, so be sure it is not hot! Some coolant will drip onto the underbody and onto the ground. You can't catch it unless you got a very long drain pan, so be quick once the coolant starts to drip!

The original coolant was dirty green and had particles in it. I also suspect it was somewhat oily, but I couldn't confirm because the drain pan I used was oily.

I filled the radiator with tap water and ran the engine for 5 minutes (until it reached the operating water temperature). I didn't put the radiator cap to make sure the water was running. When the gauge touched 'C', I installed the cap. Originally I wanted to wait until the radiator fan turned on, but it never did. Also, there's actually no need to run the engine for so long — it can be stopped once the upper radiator hose is hot.

Then I waited for 30 minutes for the engine to cool down (until the gauge touched 'C'). This was the time consuming part. Bring lots of reading materials! The water at this point was warm — you still can fish for the drain plug that you'll inevitably drop into the pan, but you can't put your hand there for more than a few seconds at a time. Warning: don't ever open the radiator cap until the gauge points to 'C'!

The water after the first flush was still dirty green. The water after the second flush was pretty clear.

I then flushed the radiator twice with distilled water. This was to dilute the tap water. Before the first flush, 2 litres of tap water was left. After the first flush, 667 ml was left. After the second flush, 222 ml was left. Finally, I put in 2.5 litres of coolant — I wanted a mix of 40% coolant — and topped it up with distilled water.

The new coolant smells sweet. :-) The old coolant had no smell at all. But just in case, I flushed it with water to dilute it.

2 Jul 2007 The coolant reservoir is very dirty. It needs to be scrubbed clean.

Tools required: 10mm socket wrench.

There are 3 screws to remove. The bottom screw is very difficult to remove without a socket extension.

Gave the reservoir a good scrubbing. Did the best I could, but there were still some sludge inside.

10 Jul 2007 239,713 [Apr 2007] I want to inspect the oxygen sensor to see if it's clogged up. I wasn't able to remove it! Will try again once I get a 22 mm crowfoot wrench. I also need to test it with a voltmeter to see if it's responding well or not.

I highly suspect my high FC is due to the oxygen sensor. A non-working oxygen sensor will cause Miata's ECU to work in "open-loop" mode, meaning it will dump a lot of fuel into the engine. Result: high FC and carbon coated spark plugs.

[Jun 2007] I have measured the sensor output and it was at 0.9x volts whether the engine was at idle, 3000 rpm or 5000 rpm! Either I measured it wrongly or the sensor was spoilt.

[Jul 2007] Inspected the oxygen sensor. You can tell it's very old by its oxidized state. Only the top part is filled with carbon.

Tools required: 22mm crowfoot wrench.

Be sure to unplug the other end of the O2 sensor first. There is very little space to fit the wrench without removing the exhaust heat shield, but it can be done.

12 Jul 2007 239,750 Changed spark plugs and spark plug leads. I checked the new spark plugs were gapped at 0.9 mm.

The secondary ignition coils measure 12.7 kohms.

Heard whistling sound from the engine. To be investigated further. Don't know if it's due to this change or the octane 98 fuel.

[23 Jul 2007] Took out the first sparkplug for inspection. It looked very clean, indicating lean fuel mixture — strange. I retightened all sparkplugs. The whistling sound disappeared.

23 Jul 2007 239,930 Changed the air filter. The old air filter was very dirty. Tuned the idle speed with the new air filter too.
25 Jul 2007 I broke the negative horn wire when trying to remove the steering wheel. Need to buy an allen key set to fix this properly.

[25 Aug 2007] I taped the negative horn wire to one of the metal screws as a temporary measure.

29 Jul 2007 240,050 [May 2007] I believe the current fuel filter has not been changed for a long time, judging from the state of the air filter, so I definitely want to change it at least once. After changing the fuel filter, I can then use fuel injector cleaner additive to clean the fuel injectors.

May need additional tools to change the fuel filter. My main worry is fuel spillage.

Tools required: jackstand, screwdriver, 10mm socket wrench, plier, newspaper, cup and safety glasses.

I don't know who said it's possible to access the fuel filter without jacking up the rear of the car. It may be doable, but it would be a very tight fit.

It took me a long time to remove the fuel filter cover. One of the screws was stuck to its rubber washer. Used WD-40 to loosen it before the two finally separated.

Remember to open the fuel cap, pull the fuel pump relay line and then start the engine to depressurize the fuel lines. I did not remove the negative battery terminal.

I removed the exit hose from the fuel filter first. I gripped the metal part of the fuel filter and pushed the hose out with the plier. It was slow work, and the trick was not to press the plier too hard — the intention was not to grip the metal part! This hose was still easy cos I could pull the hose to make it come out faster.

I was prepared for the petrol to drip out of the fuel filter once the hose was disconnected, so I used newspaper to soak it. However, it didn't stop after 10 seconds or so, so I plugged the hose back and waited for the fumes to dissipate. Inhaling concentrated petrol at such a close range made me dizzy.

I wanted to remove the bracket and put it on the new filter first, but it could only be removed via the exit hose. However, since it looked like it would be harder to remove the entry hose with a dangling fuel filter, I loosened the entry hose halfway first.

I unscrewed the fuel filter bracket so that the fuel filter was now dangling. I then disconnected the exit hose to remove the bracket. To my surprise, petrol continued to drip out. I wiggled the exit hose too much, so when it disconnected, the petrol flew all over the place, including on my face! Thank goodness for my glasses! I got some on my nose. Very foul smelling. I quickly reconnected the hose and washed up.

It was then that I realized the fuel must be coming from the fuel tank! Quick change in plan: I decided to remove the entry hose first, with the new filter within reach so that I could swap the two immediately.

Once I disconnected the entry hose, fuel started dripping from it, so I quickly connected the new fuel filter to it. I disconnected the exit hose from the old fuel filter and connected it to the new one. No dripping.

Once I got the old fuel filter out, I could take my own sweet time to remove the bracket. It was still pretty good shape. No rust. I had to disconnect the exit hose from the new fuel filter to put the bracket on. Again, no dripping.

After that, it's just screwing the bracket to the car body, installing back the cover and priming the fuel system.

When priming the fuel system, you can hear a whirling sound from the cabin if it's quiet. I didn't prime properly and the car failed to start after two cranks. I then made sure the F/P and ground are connected properly and then the car primed properly.

I must say I did a real lousy job at this. But it doesn't look like it would be much simpler the second time round. This is definitely something I do not look forward to.

When disconnecting the hoses, do not use too much force, or it's hard to control where the petrol spill. Safety glasses is a must. Use newspaper or rags to cover the hose just before pulling it apart.

20 Aug 2007 240,368 Sent to Autolodge to service the following:
  • top up air-con gas, check for leak as well
  • replace flexible clutch hose and bleed clutch fluid
  • check petrol fume in the boot
  • blow particles out from the third sparkplug chamber
29 Aug 2007 240,531 Replaced the oxygen sensor. To monitor fuel consumption.

Tools required: 22mm crowfoot wrench.

26 Jan 2008 242,595 Replaced the seat belt stalks. Nothing wrong with them, except the red buttons were faded.

Interestingly, the old fasteners use a 16mm nut. The new ones use a 17mm nut.

Tools required: 16mm, 17mm wrench.

19 Feb 2008 242,786 To replace the combination switch as the light switch stalk and the turn signal canceller are not working perfectly. They are still working properly, though, so this is a low priority task.

[26 Jul 2007] Managed to remove the wheel with a gear removal tool. The plastic part holding the light switch stalk has flexed and is loose. It doesn't look like it can be repaired.

Changed the combination switch. The old clamp was very tight and I stripped the screw. Luckily I could use a 8mm wrench to turn it — I should have done that in the first place.

Once the steering wheel was removed, it was very easy to take out the combination switch. You need to loosen the clamp by a lot, then lift up the catch at the top of the combination switch and then it can be pulled out easily.

Tools required to remove the steering wheel: gear removal tool, 21mm wrench. The gear removal tool I used requires a 17mm wrench to turn it.

Tools required: 8mm wrench.

26 April 2008 243,743 The tyre treads are very near the minimum tread depth. I estimate that I'll need to replace them by the end of the year (2007). One option is to reuse the current rims and get back the same 205/45/R16 Michelin tyres. This would set me back about $800. However, I'm also looking at lighter rims and tyres.

[Apr 2008] Finally replaced the tyres! The new tyres are Michelin PP2 205/45/R16. Cost is $668. Polished two rims at the same time for $30.

12 May 2008 243,931 I want to make sure the ignition timing is correct and not too advanced. To do this, I need to buy a timing light. Can't seem to find this locally, need to get from the Internet.

An ignition timing that is set too advanced will cause high FC too, that's why I want to make sure it's set properly.

[May 2008] Borrowed a timing gun from a ITE lecturer. The timing hovers between 10 to 12 degrees. I don't need to adjust the CAS.

Tools required: paper clip, timing gun.

TBD I want to inspect all other sensors to make sure they are working properly.
TBD I want to bleed the brake and clutch lines. Although the brake reservoir is very clean, I read that the dirty stuff is in the calipers. Bleeding the lines will be challenging because the fluid is corrosive.

Online posts mention the need to use a flare nut wrench. I wonder why a regular wrench will not work.

TBD The radiator has hairline cracks. It may last only another year or so. The upper hose is new, but the lower one is old and hardened already. The other coolant hoses (7 or so) should be old as well — only the most visible one was replaced, typical of workshops. However, it may not be possible to replace all the hoses without removing the engine.
TBD I would like to replace the springs and the shocks. It doesn't look easy without the spring compressor.

[Feb 2008] I have bought the dampers and bump stoppers. I wanted to buy a new set of springs, but the parts shopkeeper told me springs don't spoil. Nevertheless, I have a used set that I had bought earlier. I didn't get the rubber mounting too cos it was very expensive ($65 per piece) and the shopkeeper told me people seldom change that.

Now the only thing left is to learn how to change the shocks/springs!

(void *) &NHY;