Overheating at the track? Possibly bad head gaskets

[NSX-Racer]

As I had the water temp gauge very often in the red zone during my last track events I threw out my old radiator with many bent fins and put in a new custom built competition radiator. Surprise: Water still gets too hot. Turned out now to be the same head gasket problem that Prime member Dangermoney already had some time ago. Read the full story here . Thanks again - without Dangermoney I possibly would have had to search some more months for the cause (as he did in his case).

The weird things with this gasket issue are: Car doesn't overheat during usual street use, you won't detect it with usual compression testing or checking the coolant system, you see nothing unusual in the colour of your oil, you may not even experience any leaks.

 

[Hrant]

This is quite helpful as the overheating issue at the track has been discussed on the Track forum as well.

http://www.nsxprime.com/forums/showthread.php?t=35953&highlight=overheating

But in the cases that I am familiar with, the overheating occured when the outside ambient temps were in the 90sF and above. I am not aware of similar problems when temps have been lower, even with the DaliRacing radiator guard (street version). In fact, my needle doesn't budge over the middle mark on days when the ambient temps are in the 60-70F range.

It doesn't appear that in your case the ambient temps were high. So perhaps the gasket issue may not necessarily apply to those of us who only experience overheating when the ambient temps are high?

TIA

 

[NSX-Racer]

According to some other Prime members a proper NSX shouldn't overheat even in a high temperature ambience on the track. In the case of dangermoney he had this issue at Phoenix/Arizona where it's not really cold AFAIK. With the new gaskets the water temp of his track car stays about in the middle of the gauge.

 

[ATERPAK]

Well it did seem that you could detect it in the coolant with the proper test. Getting oil in the coolant isn't necessarily the problem with this engine as in others. What it seems to be showing me is that hot exhast gases from the combustion chamer are entering the water stream heating the water even hotter than normal. No water is entering the combustion chamber in this process so when you check your coolant level after it cools, it seems to be normal. I'm wondering if just retorquing the heads might also solve that problem. It use to be that all engines had to have their heads retorqued in the past, and I'm wondering if this might be a possiblilty with the NSX.

 

[TampaBayNSX-R]

I experienced the same frustrating symptoms with my car awhile back. On the street and even under aggressive street driving conditions the car ran fine. As soon as you put her on the track, two laps you'd be in the red. No messy symptoms etc. I even did the aftermarket radiator upgrade, coolant system flush, new thermostat etc...Next track event, two laps in...red. Turns out I had a blown head gasket. This problem was especially difficult to diagnose because the symptoms only seem to make themselves known during a track event.

 

[Like007]

I had same problem
Igor

 

[NSX-Racer]

Short interim report: My head gaskets have small leaks between the cylinders, the other parts of them are relatively okay (will be replaced of course). Heads surfaces will be machined te remove residue of gaskets and to assure plain surfaces. I don't think that retorqueing the heads as aterpak suggested would have solved the problem.

Timing belt will be replaced again (has been done about 25,000 kilometres ago) because it's easy to do now (although my tech does the whole operation without removing the whole engine) and it shows some signs of wear (no major damage).

Many bolts of the exhaust covers were completely rusted in their holes - will be redrilled. That made the operation a lot more time consuming than expected. No other parts of engine mounting and rear suspension etc. are bad.

Engine head interiors (camshaft etc.) look like new (after more than 125,000 kilometers including more than 15,000 km hard track track driving) - techie says he didn't see such good shape in any other car with this mileage. Of course he was not really surprised because he works on the car until it became a track-only-car (nearly 5 years ago) and learned a lot about the quality of the NSX comparing to Porsches, Bimmers, Mercedes etc.

 

[hlweyl]

Do they automatically machine the heads even if they prove to be straight by using a machined straight edge? I always thought that they only machine the heads if absolutely necessary and when they do that, you actually increase compression ratio. Sometimes they will actually install slightly thicker gaskets to compensate.

Good luck and glad you found the problem.

 

[NSX-Racer]

Thanks for your wishes. I guess they do it when some residue of the gaskets is somehow burnt into the surface in the enormous heat there. Don't ask me to which extend my heads are or will be machined - they are still at the engine shop. I hope they know what they do there.

BTW: Would a bit more compression be bad? Isn't that part of some N/A tuning to get more HPs? Just asking - I'm no engineer.

 

[hlweyl]

A little more compression is never a bad thing. Shaving the heads is an old hot rodder trick to give them a little more compression without changing the pistons. I would assume the amount they need to shave just to get gasket residue off is negligible anyway. Usually they can get most of it off by using a 3M scouring pad hooked to a high speed drill.

Hope it works out great for you.

 

[ATERPAK]

You don't machine heads just to remove old gasket material. There are other less invasive methods to do that. You shave heads because they have become warped in some way and are no longer flat on the surface. They should be measured for this first and then if needed then can be shaved.

By the way, I've been told that the head gasket on the NSX is made of steel, possibly stainless, and it should not leave any gasket material on the heads. This gasket is very similar to the exhaust gaskets which I know are stainless steel of very high quality.

Finally our Master NSX tech at Niello has not heard of any problems in this area of overheating at the track only and not on the street. He also knows of no indidcation that you would have to retorque the heads to eliminate this potential. I've asked Comptech for a comment but I haven't had a return call from them as of yet. It also seems very strange to me that so many cars of different years are experiencing the same thing at this track and have no problems on the street. For us to all have blown head gaskets is quite a stretch and highly unlikely to me.

 

[NSX-Racer]

Little update: My techie encountered a bad thread in one of the cylinder banks when he remounted the heads after replacing the head gaskets. Thread had to be rebuilt. Maybe that was one of the causes for the gasket failure.

 

[NSX-Racer]

Another update: After many weeks of waiting my techie's now sure he found the cause for the latest power loss and overheating issues. During remounting of all the engine parts after replacing the head gaskets a cable was bent and apparently broken between a camshaft sensor and the ECU. So the ECU missed some data and went into emergency run mode.

Cable's now fixed and the engine runs fine again - we will now try to check if the overheating issue is also fixed.

 

[RP-Motorsports]

We had an overheating problem last year (all year) We tried everything (burping air out of the system, water wetter, thermostat, new overflow tank, fans on etc. After a year, we finally found the cause.....................

The cap on the overflow tank was NOT double locked!!!! The cap turns to lock once, then you must push down and turn it again to a second position! (Dali or SOS tanks)This took care of all of the air that was leaking "into" the system, causing the overheating.

 

[NSX-Racer]

The cap on the overflow tank was NOT double locked!!!! The cap turns to lock once, then you must push down and turn it again to a second position! (Dali or SOS tanks)This took care of all of the air that was leaking "into" the system, causing the overheating.

Wow - is that the case with the stock bottle too?

 

[Alittleboost]

Another update: After many weeks of waiting my techie's now sure he found the cause for the latest power loss and overheating issues. During remounting of all the engine parts after replacing the head gaskets a cable was bent and apparently broken between a camshaft sensor and the ECU. So the ECU missed some data and went into emergency run mode.

Cable's now fixed and the engine runs fine again - we will now try to check if the overheating issue is also fixed.

With this cable broken this didn't produce a CEL? (Check engine light)?...I thought everytime the ECU runs into limp mode the CEL light would come on indicating a problem with the motor, since you said the cable was a sensor.

 

[NSX-Racer]

With this cable broken this didn't produce a CEL? (Check engine light)?...I thought everytime the ECU runs into limp mode the CEL light would come on indicating a problem with the motor, since you said the cable was a sensor.

Weired - I didn't get a CEL and there was no error code stored. Yes, I checked that the CEL bulb works okay. The cable was indeed from one of the cam position sensors - the sensor itself was and is okay. Don't asked me why I had no CEL - I would have been glad if I could have read out a code at the track to get a hint where the problem was.

 

[RP-Motorsports]

Wow - is that the case with the stock bottle too?

I am not sure, since all of us have aftermarket tanks. I would think the same would apply though. If it is NOT perfectly tight, it will draw air in the NSX pressurized system.