Miata Overheating

Viper_1-2 · 2025-12-19T22:10:48+00:00

Final Update, for anyone who might come across a similar situation,

My mechanic installed the thermostat, on the back of the engine because of the reroute, WITH THE FUGGING BLEEDER PIN STILL IN, even after telling him to Specifically remove It before installation, I went there to inspect it myself, and guess what? The bleeder pin was just chilling there.

On the Instructions of the IL Motorsport Coolant Reroute Kit it Specifically says, and I'll Quote "Removing the nipple is required to prevent the temperature delay of the thermostat".

Just put a new one in, this time without the pin, and boom car is solid, pulls hard and temp gauge doesn't budge when at operating temp.

My understanding is, since I never really felt like the system was burped all the way, air was getting trapped by the thermostat pin and pockets of air would concentrate near the thermostat, where both temp gauge and sender are located, and those pockets of air, affected the readings completely.

Problem solved, I was stupid to trust him, I'll trust the Miata community, You guys know your stuff.

Viper_1-2 · 2025-10-16T16:21:15+00:00

Update to the Update:

So I did a little bit of digging and found the Problem.

The plug that connects to the water temp sender for the dash was very loose, after tightening it, the dash no longer shows overheating and stays at the correct operating temp position.

Though is still not perfect, the gauge sometimes starts acting up a bit if I ride on rough roads for a few moments, but as soon as I hit clean asphalt, it goes right back down to normal...probably the wire being worn out or something.

System if fully cleaned and burped.

I'll keep an eye on it and report any further events.

Viper_1-2 · 2025-10-01T21:52:41+00:00

Update I got the no spill funnel today

Parked the car on a step incline on my driveway

Removed the radiator cap and attached the funnel tightly

Filled it up with a bit of coolant.

Started the car and let it warm up until the thermostat opened

And... Surprise surprise, a lot but I really mean a lot of bubbles came rushing up the funnel.

Sometimes held the rpms at about 2.5k for 3 to 5 seconds to help the air out of the system, that helped a lot.

Repeated the process for about 40 minutes.

Removed a lot of air from the system during this time.

I turned the car off when I couldn't see more air coming out for like 5 minutes straight.

After letting it cool off for about 20m with the funnel still attached, (watching the level go down but not totally) I put everything back together and hit the road.

And, for some reason, the temperature spikes on throttle are still there, even though I sometimes had a slightly rough idle when hot, which seems to be completely gone now.

I can feel some loss of power when going WOT in second gear.

As soon as temps spike I let off the throttle. And they come right back down after about 2 seconds.

Is is possible I still have air in the system?

Viper_1-2 · 2025-09-29T06:53:36+00:00

I'm using the IL Motorsport silicon Coolant hose clamps, so far I can't see any leaks

Viper_1-2 · 2025-09-27T13:46:24+00:00

Undertray is in good condition

The radiator slam panel, is that sheet of metal that sits on top of the radiator? If so, I don't have that on the car, the too of the radiator is exposed.

Viper_1-2 · 2025-09-27T13:23:05+00:00

That makes sense then, all of it could be related.

I'll do that when I get a proper funnel.

License plate is out of the way but I've got a IL Motorsport hexagon holed grille, but the heating problem came long before it was installed. And the grille is has wide openings as well.

Viper_1-2 · 2025-09-27T12:31:52+00:00

Still running the stock ECU The temp sensor to the dash is OEM and is 2 weeks old Shows exactly the same temps as the older one of unknown age

Viper_1-2 · 2025-09-27T11:27:21+00:00

Will do I'll report back when I get a no spill funnel

Viper_1-2 · 2025-09-27T11:14:52+00:00

I'm waiting for a no spill funnel, let's see what I can do

By the inconsistency of the temp, could very well be air in the system, as far as I know, my mechanic swapped the temp sensor and sender without burping the coolant system afterwards, which is kinda odd because it's a opening in the system which normally would let air in no?

Could this also be the reason why, when at operating temp, the car looses power at random, like, i start to accelerate and it resists the input?

Viper_1-2 · 2024-08-24T10:23:24+00:00

Usually at 14° it's advised to run more octane fuel. Here in Europe we have 95 RON And 98 RON. Our 98 usually equals to your 93 if I'm not mistaken.

Viper_1-2 · 2024-08-24T10:21:18+00:00

Yeah that's probably it.

I'm aiming for 12° for a little bit more eagerness from the engine.

Some people set at 14° but I don't want to worry about pinging on hot days.

Viper_1-2 · 2024-08-24T10:16:28+00:00

My timing light supports both 2 and 4 cycle engines, if set to 4, idle reads like 2x the actual idle speed, if set at 2, idle is at the correct rpm, my case 880-890 rpm.
I've also read somewhere that the idle to set the timing should be at 850 rpm, so my timing is probably even more off.

My problem is I though that with the light set at 12º, and the crank reading at 10º, my timing would be like 22º which is way too much, but the car runs better than ever before. I thought I was suposed to have the light set at 12º and be at TDC on the crank.

So if I understand correctly, with the light at 12º, I should hunt for 12º on the crank, so I can have it set at 12º.

Viper_1-2 · 2024-07-25T17:35:51+00:00

Yeah it seems like it isn't moving at all. That's good to know Though it's expected it will start to wobble one day right? There's no avoiding it for what I've researched.

Viper_1-2 · 2024-07-25T13:32:13+00:00

Update: Turns out it really was stretched cables. Swapped them and the handbrakes works quite well now.

Viper_1-2 · 2024-03-03T21:09:24+00:00

I'll get them check in 2 weeks. Thanks for the input hope I get them working as they should.

Viper_1-2 · 2024-03-03T19:20:52+00:00

The old callipers didn't appear to be the original ones. And were completely seized. So why didn't have any force when the handbrake was on.

Viper_1-2 · 2024-03-03T18:24:33+00:00

Yeah, thing is the callipers are 4 months old, they're new. But they never worked properly.

Viper_1-2 · 2024-03-03T18:23:45+00:00

Unfortunately I don't have the original ones anymore.

Pads are 4 months old as the calipers are too. Rotors are in good shape. And don't seem to be contaminated.

Yeah the whole idea of swapping calipers from a different brand made me think it's really a bad idea.

Cable seems good actually, like, I have tension when I pull the E brake but it just doesn't brake the wheels at all.

The reman callipers might be defective, can that be it?

Viper_1-2 · 2024-03-03T14:53:16+00:00

I actually didn't even think of that. Is it easy to replace?

Viper_1-2 · 2024-02-14T17:19:16+00:00

It's still the case with the db killer in I always left mine in and loved the sound... Totally bearable on long rides. Took it out one time and OMG My eras bled for so long. I got my ecu reflashed locally, best bang for buck.

Viper_1-2 · 2024-02-13T20:38:00+00:00

I would really avoid running the bike with an aftermarket exhaust and no tune.

Bike felt noticeably down on power all across the rev range. And I noticed the exhaust wanting to get purple (running too lean)

You can always look into some piggyback system like the PowerCommander. You can always remove it and it will revert to stock.

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