Advice needed - head gasket

[6flat]

I am doing a timing belt and coolant hose refresh on the NSX and noticed a bit of build up along the lower head gaskets front and rear. Here are the details to go along with the pics:

1991 NSX manual
43,000 miles
Garage queen, rarely driven

My questions are:
1) Do you think I need new head gaskets?
2) How much should a head gasket job cost?

Thanks

 

[SWFL_NSX]

I am doing a timing belt and coolant hose refresh on the NSX and noticed a bit of build up along the lower head gaskets front and rear. Here are the details to go along with the pics:

1991 NSX manual
43,000 miles
Garage queen, rarely driven

My questions are:
1) Do you think I need new head gaskets?
2) How much should a head gasket job cost?

Thanks

Welcome to Prime! My amateur .02-

HG failures aren't very common in the early 3.0 engine and I wouldn't decide based solely on the pictures. Proper diagnosis would be from a cooling system pressure check and a block test using dye. The pressure check should show an issue between the water jacket and the outside, and the block dye should show an issue between the combustion chamber and the water jacket. I'm assuming that you're not getting white smoke from the exhaust or milky oil.

I can't comment on price, but please get a mechanic who knows these cars to do any needed work. They may suggest additional items like replacing the LMAs, various oil seals, and cam caps while the heads are removed, and will hopefully know some of the NSX-specific tricks of this job, such as properly re-sealing the coil covers.

 

[Valhalla]

I agree with SWFL_NSX's assessment. Get it checked out by someone trustworthy. Here is a link to Mexiricer's build and he just did the major maintenance which I did last year. The 3.0 motor is more robust when it comes to the head gasket but all belts, hoses, WP, LMA's, seals, etc should be changed out while the motor is out. Pay for it once and drive with no worry's for the next 7+ years. Here is Mexiricer's link;
http://www.nsxprime.com/forum/showthread.php/149305-MexiRicer-s-97-MCB/page20

 

[Old Guy]

Absent other symptoms, on the surface this might be a coolant leak past the gasket not involving the combustion chamber (yet). Pressurizing the cooling system and checking for loss of pressure may work; but, can take a long long time if the leak is small. You may need to crank up the test pressure to get a result which can cause leakage at places that were not leaking before. The UV dye in the coolant can be an effective test. With a very small leak if it doesn't show up immediately it may materialize in a couple of days - been there!

 

[drew]

Do you have any symptoms of a bad head gasket? Losing or have contaminated coolant? Losing or have contaminated oil? Loss in compression, test for fluctuations in vacuum?

If not, you are just looking at some oxidation, which is to be expected on a 30-year-old engine.

Keep Calm and Timing Belt On!

 

[6flat]

Thank you for the advice, everyone. I hadn't had any symptoms of a bad HG but the car also probably hasn't been driven far enough in the last few years for symptoms to show up if there was an issue. I'll continue on with the maintenance work I had planned and keep a close eye on the oil, coolant and exhaust.

 

[goldNSX]

As it's a garage queen who much are you going to drive it in the next years?

As it seems to be a leak from the coolant to the outside the proper pressure test will tell you quite a lot. An additional oil analysis would show if there's any coolant present long before you notice any ill effects like milky oil on the dipstick. A third test would be a CO-test of the coolant.

If these tests check out ok I wouldn't touch the HG as long as you keep it as a garage queen.

 

[6flat]

As it's a garage queen who much are you going to drive it in the next years?

As it seems to be a leak from the coolant to the outside the proper pressure test will tell you quite a lot. An additional oil analysis would show if there's any coolant present long before you notice any ill effects like milky oil on the dipstick. A third test would be a CO-test of the coolant.

If these tests check out ok I wouldn't touch the HG as long as you keep it as a garage queen.

Roger that- sounds reasonable. Thanks

 

[Elite]

Agreed. Keep an eye on it, but don't worry about it. Not likely an issue, I've seen this on others that had no issues.

 

[latzke]

I don't know what is meant by "lower" head gaskets. There are only two head gaskets - one per bank.

The pre-1997 head gaskets have similar reliability as early Legend head gaskets. Not horrible like Subaru, but not great either. I think issues are more common than realized, and they can start out small and relatively unnoticeable. Mine became pretty noticeable when the result was displacement/loss of coolant. However, based on how clean my oil stays after the change compared to the last few changes before the issue - I think it came on slowly and not suddenly. Anyway, I have a detailed write-up (link below) that can help you (or tech you select) get things dialed in right. Even though I did all the work myself, I used a trusted independent shop to confirm the diagnosis first (for whatever reason, the tester I was using did not indicate a leak - but it was there and the shop easily confirmed 100%).

http://www.nsxprime.com/forum/showthread.php/171999-Head-Gaskets-Achilles-Heel-of-3-0L-Engines

 

[SWFL_NSX]

The pre-1997 head gaskets have similar reliability as early Legend head gaskets.

http://www.nsxprime.com/forum/showthread.php/171999-Head-Gaskets-Achilles-Heel-of-3-0L-Engines

Nothing to add, but that's a killer thread-thanks.