I read a bunch of other threads where people pretty much had the exact same problem as I do and it ended up being a head gasket, but I'm gonna post anyways.

Yesterday during my second to last session of the day at the very end I noticed the temperature on the stock gage was a little higher than normal. It was probably at the 3rd mark (halfway between normal and peak). It was the end of the session so I just did a cool down lap and it soon went back to normal temp.

The last session of the day about 15 minutes in it started doing the same thing. It wasn't maxing out the gage, but again about halfway in between normal and overheating. So I just cruised around for about half a lap and it went back to normal. I then proceeded to continue driving 100%, except I would shift at 6500 instead of 7000. There are a few places though where it would top out in 4th and I didn't want to shift into 5th only to have to slam on the brakes a millisecond later so it did get up to 7k a few times. Anyways I probably went for about 2 more laps and it started doing it again. It was the end of the session again so I did the cool down lap and was done for hte day.

So today I did a little investigating. The coolant level did not change one bit, and there's no sign of coolant in the oil. I did a leakdown test and held pressure in each cylinder for a while to see if the coolant level would change or bubble or anything. It didn't. I also looked down each cylinder to see if the pistons looked really clean like it had been burning coolant. All cylinders looked kind of shiny black, except for one cylinder which was dull black. It pretty much looked the same as the others except slightly dull. This cylinder also happens to be the cylinder that has about 15% leakdown. I did a leakdown test about a month ago and found that out, and it hasn't changed. I'm pretty sure it's just the rings since I can feel air coming out of my crankcase breather.

I also did a coolant pressure test. I pressurized the system to 1.0 bar for about 20 minutes. It held pressure pretty much perfectly...maybe losing about 0.02-0.025 bar, which 1) is nothing and 2) probably is from the tool not sealing perfectly.

I was planning on putting in an S54 M coupe radiator and euro M3 expansion tank anyways since I'm on the original radiator, and just running water with water wetter (right now there's 50/50 coolant water). I also plan on removing the A/C condenser (and all the other AC stuff), and adding the undertray piece that is missing. Hopefully all of that will solve the problem, but the only way to tell is take it back to the track, and I don't want to spend a shitload of money on track fees, gas to get there/back, etc and only get half a session in before having to go home.

Do you think that with the power I'm putting down with full schrick cam kit, M50 manifold, exhaust, etc and probably running lean on AA software that it was just running hot because it was pretty hot out (probably 90 degrees or so) and my cooling system just isn't up to par with the stock radiator running with 50/50 coolant/water and no undertray? Last summer I put in a new water pump and did the fan delete mod, btw.

My car did the same thing last year...hot for a few laps...I'd back off...it would cool down, and then start to overheat again.

The recent overheating problem I had would start under heavy braking and then the motor would cool down once I was moving again and getting air through the radiator. That time it turned out to be a failing primary belt tensioner. It was causing my belt to slip off my water pump pulley when there was a rapid RPM change (heavy braking), which was enough to initiate overheating.

Do you have good tension on your main drive belt?

Is your radiator clogged?

The headgasket is a big repair job. I hope that isn't in your future.

I'd be really happy if it were something as simple as that... I'll have to check. I know the tensioner is original, I replaced the belt last year.

I can't remember exactly when the change occured, but the early E36 water pump plastic impellers are known for deteriorating with time and loosing parts of the impeller. A 96 has to be close to the change over to the composite impeller that doesn't suffer from that problem.

If your pump is original, replacement with a new OE part (or the EMP Stewart pump) and replacement of the thermostat & housing would be a good idea.

I replaced the pump a couple thousand miles ago/last summer.

Even though you replaced the pump it could still be that. My car was doing the same thing (sort of) it got hot sitting and would not go lower than a bit above 1/2. I changed the thermostat and that cured it. When replacing the thermostat I drilled a hole in the metal housing upon request of my mechanic. It now runs at 1/4.

I replaced my pump about 3 years ago. I Couldn't tell if it was metal or plastic. About 18 months later it failed...shop said it was a plastic one.

I read a bunch of other threads where people pretty much had the exact same problem as I do and it ended up being a head gasket, but I'm gonna post anyways.

Yesterday during my second to last session of the day at the very end I noticed the temperature on the stock gage was a little higher than normal.

You know the stock gauge is an "oh shit" gauge not an actual temp gauge. If it's not sitting perfectly straight up then you have a problem. Solve the problem don't try to find excuses for it.

I installed a Spa temp gauge to see water temps my car was running and this was after the stock gauge started moving towards the red at my last track event and I don't rely on it anymore. The problem was a leak in a fitting for a throttle body heater hose so that's what the gauge was telling me. I would not have pushed the car any further after the gauge started moving, doing this will get you either a blown head gasket or worse damage the head.

Now with the Spa gauge I can see that from anywhere between 160-ish up to 200 degrees F the stock gauge does nothing but sit straight up. I haven't run any hotter than that but I bet it won't budge even if I do get above 200 degrees. It's only useful to tell you there is a problem in your cooling system in my opinion.

Carlos

i have also been chasing down an overheating problem. so bad that last race i ended after 7 laps thinking i blew a headgasket.

other things i am going to throw out as possible problems:
running too lean from your chip
running too lean from your injectors being dirty or inadequate
exhaust cam timed incorrectly (we found this last night on my car while installing schricks, the exhaust cam was retarded, possibly keeping the exhaust gasses in too long and causing it to overheat)

i'd say by far the most common sources of overheating are in the cooling system itself, but if replacing the radiator, water pump, t-stat, and bleeding the system doesn't do it, then start looking elsewhere

Well the good news is that I had a similar problem, but was blowing off water/coolant. It would only happen at high RPM and high load and the temp would spike on hot laps. It passed leak down and pressure tests while cold. In finally pulled the head and verified a head gasket failure. If you're not getting it hot enough to blow off coolant (past the cap) then you MAY not have a blown head gasket and simply have a fan or circulation problem.

Fix any potential circulation problems, put a real gauge on it, and get your coolant tested for exhaust gasses.

Headgasket isn't too bad once you've done it a couple of times ;)

The undertray is fairly important in cooling the engine compartment. Without it air does not flow through the engine compartment like it was designed to. I had a non-vanos M50 and could run it hard enough to get it hot on the south course at VIR. Especially in traffic. Stick the nose out of the draft and it would cool right down. When you get to higher experience levels you can run the motors hard enough on a short fast course that you can overheat them. Go to a bigger radiator. Drop the cheese on one of the nice aluminum ones and you can stop worrying about when that neck will fail. I had a stock replacement fail at 40k. Split the end tank. That was on the south course as well. I have an S54 radiator in my car now because it was a gift. When it gets to replacement time I am going aluminum.

Ryan

I read a bunch of other threads where people pretty much had the exact same problem as I do and it ended up being a head gasket, but I'm gonna post anyways.

Check the cooling system first.

But dollars to doughnuts it's your head gasket.

And Carlos is dead right about paying attention to the temperature gauge.

Pressure, compression and leakdown testing may not reveal any problem since you can't get the engine hot enough for the head gasket leak to reveal itself under test conditions.

Do you think that with the power I'm putting down with full schrick cam kit, M50 manifold, exhaust, etc and probably running lean on AA software that it was just running hot because it was pretty hot out (probably 90 degrees or so) and my cooling system just isn't up to par with the stock radiator running with 50/50 coolant/water and no undertray? Last summer I put in a new water pump and did the fan delete mod, btw.

No. Your car presumably ran OK with this setup before (right...?), so that's not it.

Why would it be running lean on the AA software? Do you mean that this isn't the right software for the hardware setup you have? (And if so why not...?) What injectors are you using?

So many questions.

Neil
96 M3 - Eurosport Cam Kit

This is also a growing concern for me. As summer is in full bloom right now, track temps are reaching the 100 F's. What are some things we can check for before heading to a full weekend of tracking in hot weather? Or for that matter (besides temp gauge) things to look for.

My car has 75k miles and a new radiator 10k miles ago. Along with m50, CAI and exhaust.


Thanks

Check the cooling system first.

But dollars to doughnuts it's your head gasket.

And Carlos is dead right about paying attention to the temperature gauge.

Pressure, compression and leakdown testing may not reveal any problem since you can't get the engine hot enough for the head gasket leak to reveal itself under test conditions.



No. Your car presumably ran OK with this setup before (right...?), so that's not it.

Why would it be running lean on the AA software? Do you mean that this isn't the right software for the hardware setup you have? (And if so why not...?) What injectors are you using?

So many questions.

Neil
96 M3 - Eurosport Cam Kit

It's all setup right. 24# injectors, porsche hfm, M50 manifold, samco boot, schrick cams, 3.5" intake, uuc catback exhaust with AA software. I've just seen a lot of posts where people post their dyno graphs with AA software and they are running lean. This was the third weekend this year at the track and didn't have any problems before, but it was also not very hot before.

Well I put in an aluminum radiator, removed the condenser, fan, and compressor and made an underpanel and it started overheating at the track again during the second session which sucked and wasted a lot of money. Any more suggestions before I pull the head?

If you know the water pump is good, then the head is warped or the headgasket has a leak.

I pulled the head off today and I've been examining it and the head gasket. I can't find any obvious signs of leakage, but I don't have much experience with head gaskets. I did notice however that all but the rear-most cylinder the pistons were kind of shiny...black but shiny whereas the back cylinder was black and not shiny. I hope the head isn't warped... I'm trying to figure out how to check that now.

I pulled the head off today and I've been examining it and the head gasket. I can't find any obvious signs of leakage, but I don't have much experience with head gaskets. I did notice however that all but the rear-most cylinder the pistons were kind of shiny...black but shiny whereas the back cylinder was black and not shiny. I hope the head isn't warped... I'm trying to figure out how to check that now.

Drop off at a machine shop, have head checked for flat, also consider pressure
test for hairline cracks.

..

Drop off at a machine shop, have head checked for flat, also consider pressure
test for hairline cracks.

..

Well I checked it with a straight edge and it does not appear to be warped. Here's some pics I'm kind of wondering about the burn marks around the ports which water flows through.
http://img.photobucket.com/albums/v374/hammdy/DSC01121.jpg
http://img.photobucket.com/albums/v374/hammdy/DSC01120.jpg

A little hard to see on a laptop, any visible paths to a cylinder or degrdation on the surface of the gasket??

A little hard to see on a laptop, any visible paths to a cylinder or degrdation on the surface of the gasket??

no i looked hard for that but couldn't see any

I experienced a similar overheating problem on the track. My whole cooling system was replaced over a year ago. I was tucked behind a RX8 at the streets of willow for about 6 laps when the temp gauge went to 3/4. Once I backed off the Rx8 the temp went back to normal. I check under the hood after the session to find that my coolant cap was bleeding off some pressure (and coolant). Anyone have this happen to them and know of any ways to make sure this dosen't happen again.

This is starting to sound like an AA meeting. Hi. My name is and I have an overheating issue at the track.
As Carlos says, the stock gauge is shit. My car saw temps of 220º this weekend at VIR on the North Course and the idiot gauge stayed in the middle. I did manage to get some air out of the system and Sunday's temps were down about 10º. Ambient temps were in the mid-90s.
The car already has a Fluidyne radiator, oil cooler, undertray and other plastic bits. The hoses were soft after cooling and no water was blown out. So this week, I will install a Stewart pump and a lower temp thermostat, 71º instead of 80º.
I am on the Full Course this weekend, so I will post back to let you know if the pump and thermostat changed anything.

Joel

With your straight edge, can you tell whether the head is warped by 0.003?

Philip Bradley

It's definately not warped I couldn't get a .003 feeler gauge under the straight edge at any points.

I looked closely at the head and gasket today and I'm pretty positive that it's leaking at those really small coolant holes that are between each cylinder circled in red. Not all of them, but most of them.

As Carlos witnessed, I had the same kind of overheating issues in my S50, which resulted in a DNF at my last race at Mid-Ohio. My head gasket showed only the slightest evidence of burn through and the head was only slightly out of true. Got it all fixed and low and behold, no more overheating issues.

This is starting to sound like an AA meeting. Hi. My name is and I have an overheating issue at the track.
As Carlos says, the stock gauge is shit. My car saw temps of 220º this weekend at VIR on the North Course and the idiot gauge stayed in the middle. I did manage to get some air out of the system and Sunday's temps were down about 10º. Ambient temps were in the mid-90s.
The car already has a Fluidyne radiator, oil cooler, undertray and other plastic bits. The hoses were soft after cooling and no water was blown out. So this week, I will install a Stewart pump and a lower temp thermostat, 71º instead of 80º.
I am on the Full Course this weekend, so I will post back to let you know if the pump and thermostat changed anything.

Joel


Please do let us know how the lower temp tstat and water pump do for you. I"m thinking of changing over to a cooler thermostat as it is extremely hot here in Vegas.

Please do let us know how the lower temp tstat and water pump do for you. I"m thinking of changing over to a cooler thermostat as it is extremely hot here in Vegas.

I did not get a chance to install the water pump and thermostat before heading off for the track. After speaking with several people who should know, I think my high temps were caused by a completely severed crankcase vent pipe.
I have converted to an S50 intake manifold with the Eurosport kit. The original vent pipe is cut and a section of heat shrink tubing is added to make it longer. Unfortunately, this tubing rests against the oil filter cover. The heat from the oil filter housing melted the heat shrink tubing and caused a vacuum leak post mass airflow sensor, which resulted in the car running lean. Lean conditions lead to higher temps.
Coolant temps this weekend were ~210º and ambient in the low 80s.
I will still install the lower thermostat and Stewart water pump.
Joel

Just FYI from some experimentation, the factory temp gauge just starts to move just as my autometer gauge hits the end, at 250.

I think my high temps were caused by a completely severed crankcase vent pipe.
I have converted to an S50 intake manifold with the Eurosport kit. The original vent pipe is cut and a section of heat shrink tubing is added to make it longer. Unfortunately, this tubing rests against the oil filter cover. The heat from the oil filter housing melted the heat shrink tubing and caused a vacuum leak post mass airflow sensor, which resulted in the car running lean. Lean conditions lead to higher temps.

You made me curious enough to go and look at mine. It has a bit more than 1/4" clearance to the filter housing lid, but since this breather tube is pretty taut it can't move enough to touch. I have the splice down near the lower end connector, which may help with the clearance.

Neil
96 M3

Just FYI from some experimentation, the factory temp gauge just starts to move just as my autometer gauge hits the end, at 250.

shit that's not good

You made me curious enough to go and look at mine. It has a bit more than 1/4" clearance to the filter housing lid, but since this breather tube is pretty taut it can't move enough to touch. I have the splice down near the lower end connector, which may help with the clearance.

Neil
96 M3

Thanks for the tip. I spliced mine with 3/4" heater hose and tie wraps. BTW, I also have the VPD Oil Cooler kit and the larger filter lid gives no clearance. Not an issue with VPD nor Eurosport. Just not a good combination.

Joel

I have at least one or two spare gaskets for the S50B32.....not full kits, just gaskets.

Let me know if you need one of them stat.

Alex.