Regarding C30A head gaskets and overheating

[Supra TT]

After having read a few threads about a few nsx owners having issues with the C30A composite head gasket, particularly after engine overheating, a new concern has triggered my paranoia about enjoying my car. Thus I am creating this thread to shed some more light on the issue and dispel some of my worries. What I would like to survey is how many of you earlier pre-97 NSX owners faced this issue and at what mileage did it occur? Please include details about regular maintenance i.e.- hoses, thermostat, FI/SC,whether you track your car, etc. Also those of whom are part of the high miles club please chime in as to whether or not you've done this 'fix' or 'preventative measure', however you prefer to look at it.
I understand that the nsx's aluminum block does not lend itself well to overheating so I'm curious to know exactly how rare, if at all, this phenomena is and to what extent does the engine have to overheat to cause cylinder head warpage. Is this worth classifying as a more/less common than not problem?

Again, this assuming all maintenance is up to date. No biases please, we're all partial to these cars.

For reference I drive a 94 5MT, have not overheated

 

[EAC]

]96 NSX - Turbo] I've never had an issue with headgaskets. I haven't touched the hoses, but I changed the T-Stat when I did the Timing Belt / Waterpump. 153K on the clock.

I don't think it happens often, but when it does, you'll definitely hear about it on the forum....

 

[BATMANs]

suring my rebuild on my 93 with 110k miles the head gaskets looked fine taking 430rwhp supercharged.

 

[USAFguy22]

Wasn't the cooling system tested in the Outback? With top speed runs as well as heat soaking idles?

 

[NSX2398]

I'm at about 185k miles and have had it since 90k without issues. I have tracked it as did the previous owner. Replaced the main coolant hoses but never the thermostat. Never had any overheating issues ever

 

[Supra TT]

Thanks for the replies guys, would love to hear from someone who has gone through a head gasket. Wondering what the temperature threshold would be should the car blow a hose and overheat.

@EAC, if you haven't replaced the hoses @153k have your flamesuit ready lol Its when a hose bursts that Ive heard overheating is right around the corner and then the inevitable head gasket/warpage follows.

 

[latzke]

I'm the guy who started this thread:
http://www.nsxprime.com/forum/showthread.php/171999

In speaking with different experienced folks I come to different conclusions about how common this is. Two examples...

Speaking with Shad I came away with the impression it is very common, at least for forced-induction vehicles or after overheating events.

On the other hand is this quote from LarryB: "Personally I think 3.0 head gaskets are fine. In hundreds of NSX’s I replaced 4 sets of head gasket in 3.0, All due to coolant hose failure/overheating."

I think the "normal" failure mode for head gaskets is catastrophic coolant loss (failure of large coolant hose), causes overheating, which warps head(s), which causes HG leak. I think the next most-common is overheating for some other reason.

I'm in what seems to be a very rare category of folks (for someone without very high horsepower) who did not experience an overheating event prior to the HG leak (though I'm only certain about no overheating event for the last 15 years, not totally sure about the first 7 - though service records from that period indicate no issue and that the hose recall was done preventatively). Failure on 1991 with 60k miles (30k of those with CTSC).

 

[d_prada1]

After having read a few threads about a few nsx owners having issues with the C30A composite head gasket, particularly after engine overheating, a new concern has triggered my paranoia about enjoying my car. Thus I am creating this thread to shed some more light on the issue and dispel some of my worries. What I would like to survey is how many of you earlier pre-97 NSX owners faced this issue and at what mileage did it occur? Please include details about regular maintenance i.e.- hoses, thermostat, FI/SC,whether you track your car, etc. Also those of whom are part of the high miles club please chime in as to whether or not you've done this 'fix' or 'preventative measure', however you prefer to look at it.
I understand that the nsx's aluminum block does not lend itself well to overheating so I'm curious to know exactly how rare, if at all, this phenomena is and to what extent does the engine have to overheat to cause cylinder head warpage. Is this worth classifying as a more/less common than not problem?

Again, this assuming all maintenance is up to date. No biases please, we're all partial to these cars.

For reference I drive a 94 5MT, have not overheated

I dont think I have ever heard of any honda blowing a headgasket and THEN overheat. Its usually the other way around. Like mentioned earlier, its usually a large amount of coolant lost, t stat stuck closed (most t stat failures I have seen due to using water and corroding the t stat shut), or a clogged radiator. Maybe im still yet inexperienced but i have never seen a headgasket "blow" without something else being the cause of the overheating. I have change PLENTY of headgaskets on hondas and almost all of them have the same problems (bad caps, cracked resovoir, bad t-stat, crappy replacement radiator or a coolant hose leaking. Then after temperatures exceed the favorable limits for the aluminum blocks, warps the block/head cause leakage through the gaskets.

Also just pay attention to you coolant temps, most cars have really crappy gauges and dont start moving up until its already too late for some aluminum blocks, it should never really show higher than the halfway point, if it starts moving up slighty i would plan to shut the car off and diagnose. Thats just me though.

As far as overheating temps, i have warped aluminum blocks/heads at 245 degress, and on the same car I monitored the coolant temps with kpro after i fixed it to see when my factory temp gauge would start moving past the halfway point and it was at 225. So dont rely on the temp gauge!! just my .02

 

[Honcho]

Add me to the list. Dealer left main coolant line bleed screw loose after a rad install and overheated at the track a few days later due to air bubble. Lifted the heads and caused small leak. 89,000 miles.

 

[tof]

Ah...So THAT'S what happened, Honcho. I hope the dealership is taking care of the work after screwing up such a simple thing.

Lesson there for us all, though. After working on any system, always check and double check that everything is buttoned up, no tools left behind, etc. I know I tend to get anxious to wrap things up when I am finishing up a maintenance job but a couple of extra minutes rechecking could save hours and possibly many dollars in the end.

 

[Honcho]

Yep, very good lesson to be learned. Actually there were TWO screw ups: (1) they left the Koyo rad bleed plug completely loose so it dumped about a liter of coolant on my garage floor the night before NSXPO; and (2) they left the bleed plug loose on the main engine bay coolant line, which we did not discover until at the track at NSXPO. Either error could have introduced enough air into the system to cause the problem. After finding the loose engine bleeder, Shad and I checked the other bleeders and they were all tight. So, my speculation is the tech was buttoning up the system after bleeding and before the last bleeder he got called away to look at something, came back, and forgot he left the bleeder loose. It was tight enough that coolant was not pouring out of it, but loose enough to let air in through the threads. Although who knows, it might have been blowing out coolant while driving for all I know. Even more upsetting is the Acura tech denied he left the plug loose (of course) and the dealer sent me off thinking I had a healthy engine, which I proceded to daily drive for 5,000 miles and then flog at the track on a 95 F day.

The icing on the cake is Chris had the engine out and apart for my major service in December. It would not have been much more labor to pull the heads at that point. Now, he has to do it all over again. The dealer told me they are "reviewing" my service history and will get back to me. If they decide to play games, I may try going through AHMC directly. I am really hoping they do the right thing though- I just want my NSX back to normal.

 

[RYU]

oh man.. sorry to hear this. What a waste of time and a huge bummer. Which one is the main coolant bleed plug? Is that one near the firewall or the one right under the TB? I think there's one under the rear bank too but I think that's a drain plug and not a bleed plug.

 

[Honcho]

Thanks man. I am so bummed out about my NSX right now- and Mrs. Honcho is furious. It was the plug near the firewall. The one under the TB was tight.

 

[Larry Bastanza]

Let's make sure we do not mix up "parts quality" with "poor workmanship". This is clearly a workmanship issue. Feel very bad for you. But you are a lawyer, I am sure this will get fixed ASAP. If you need support LMK.

Regards,
LarryB

 

[Honcho]

Let's make sure we do not mix up "parts quality" with "poor workmanship". This is clearly a workmanship issue. Feel very bad for you. But you are a lawyer, I am sure this will get fixed ASAP. If you need support LMK.

Regards,
LarryB

Thanks Larry. I try not to play up the lawyer angle in these situations, as I consider it a recourse of last resort. I'll call you to discuss off-line if things start to get hairy.

Though, as to "parts quality" I think it is a testament to the quality level of the NSX that my car is still perfectly driveable and shows no signs of an issue unless under high temps and sustained VTEC conditions. If I did not track, I may have driven it for years before the leak opened up enough to cause an overtly apparent problem. It's a tough little car.

 

[WillErickson]

Thanks Larry. I try not to play up the lawyer angle in these situations, as I consider it a recourse of last resort. I'll call you to discuss off-line if things start to get hairy.

Though, as to "parts quality" I think it is a testament to the quality level of the NSX that my car is still perfectly driveable and shows no signs of an issue unless under high temps and sustained VTEC conditions. If I did not track, I may have driven it for years before the leak opened up enough to cause an overtly apparent problem. It's a tough little car.

Sorry to hear. I won't be buying parts at that dealership any longer.

 

[goldNSX]

It was tight enough that coolant was not pouring out of it, but loose enough to let air in through the threads.

Sorry hear your story.

I don't see how a bleed plug can let in air into the coolant system while not letting coolant out of the system while the engine runs. The coolant is pressurised and is more likely to flow out than air gets in. There must be stains in the engine bay.

More likely is a air pocket within the engine.

I your car drives perfectly, smog-test OK, no coolant loss, no coolant in the oil, no bad HG test, only overheating at the track how would a dealer accept that something is wrong with the car?

 

[Honcho]

Sorry hear your story.

I don't see how a bleed plug can let in air into the coolant system while not letting coolant out of the system while the engine runs. The coolant is pressurised and is more likely to flow out than air gets in. There must be stains in the engine bay.

More likely is a air pocket within the engine.

I your car drives perfectly, smog-test OK, no coolant loss, no coolant in the oil, no bad HG test, only overheating at the track how would a dealer accept that something is wrong with the car?

Combustion gases (CO) in coolant bottle.

 

[goldNSX]

Combustion gases (CO) in coolant bottle.

Oh, this simplifies things a bit. Now, you have to proof them that they are guilty for that. Of course, they will make you believe that YOU overheated it on the track which lead to a bad HG.

In Europe, one would have a very hard time and argumentation to proof them guilty. In most cases a dealer here is better off loosing a customer than paying for the the repair. But the US is completely different.

 

[Supra TT]

Combustion gases (CO) in coolant bottle.

Please do keep us posted of what becomes of your situation, hope all is resolved

 

[RYU]

Sorry hear your story.

I don't see how a bleed plug can let in air into the coolant system while not letting coolant out of the system while the engine runs. The coolant is pressurised and is more likely to flow out than air gets in. There must be stains in the engine bay.

More likely is a air pocket within the engine.

I your car drives perfectly, smog-test OK, no coolant loss, no coolant in the oil, no bad HG test, only overheating at the track how would a dealer accept that something is wrong with the car?

There are several ways air can get into our cooling systems. Keep in mind... As the coolant pressurizes, when it gets really, hot it expands (and consequently boiling point is raised). High pressure is created as a result and coolant is pushed thru any little cracks or leaks in your cooling system. When the coolant cools down it contracts and anywhere you had a leak or crack... Guess what? It draws in air to replace the coolant that it just leaked out.

 

[UnhuZ]

Hi,

Combustion gases in coolant here also :frown:

to resume a long testament:

- Coolant loss due to bad rubber on the 2 big hoses under car.
Fixed by replacing ALL 22 hoses and a new tank (big ones replaced with Venair ones)

- Coolant loss due to little holes in main aluminium pipes (that goes from engine bay to under cabin).
Fixed by replacing with a tested free of leaks set

- Coolant loss due to little holes in both front aluminium pipes (the ones that goes arround the steering rack).
Fixed by replacing with used tested ones

since the first coolant loss, i always check the water temp almost 100% of the time.
Sometimes it started to slowly pass the middle point and i immediately either stopped the car,
or i blipped the throttle and it immediately got to normal temp (probably some air pocket passing the sensor)

Only in one ocurrence it made to the red, for a couple of seconds, and i turned the car off...
...and that was it for the Head gasket...i'm sure it died in this one event.

Now i have it stopped to replace the clutch (original from factory and it died at a little over 220.000kms),
and to open the engine and replace everything it needs (hope i don't have to get into the cylinder block).

i will replace the head gaskets for cometic ones (SOS)...no more OEM shit anymore.

Nuno

 

[latzke]

- Coolant loss due to little holes in main aluminium pipes (that goes from engine bay to under cabin).
- Coolant loss due to little holes in both front aluminium pipes (the ones that goes arround the steering rack).

Any indication as to how yours developed holes? These aluminum pipes seem pretty beefy. I would expect them to last millions of miles.

since the first coolant loss, i always check the water temp almost 100% of the time.

I'm tempted to add a SPA dual-gauge with water temp in order to have an alarm. While our cars have a temp gauge, there is no idiot light for overheat conditions.

Now i have it stopped to replace the clutch (original from factory and it died at a little over 220.000kms),
and to open the engine and replace everything it needs (hope i don't have to get into the cylinder block).

Don't forget the LMAs. Usually SoS is the cheapest source, but since you're in Europe it will probably depend on shipping costs.
http://www.nsxprime.com/forum/showt...-NSX-engines?p=1717154&viewfull=1#post1717154

 

[Onsoku]

My daily driver...no issues, per my tag line.

 

[bngl3rt]

Blew at 79k - combination of a history of poorly-installed supercharging and a service center (which I will never use again...) leaving a hose clamp out of place while replacing all the hoses.