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OMG what now 1992 Coupe LT1


Well-known member
Feb 7, 2003
Sylvester, Georgia
1992 white Coupe
I had the small coolant line to the throttle body split open and lost all coolant, I drove the car for about 2 miles leaving a stream of steam behind it. Car had been running very good until this happened. Now when I start the car it will usually start and idle and run good. BUT!! At times it will skip badly on start up, clearing up with in a minute and then idle and run good. When this happens there is a LOT of white smoke from the exhaust that looks like steam. It does not seem to be oil or fuel. The smoke goes away after a couple of minutes at idle and goes away quickly if throttle is opened and closed a few times (to about 4,000 rom). My fear is a bad head gasket, what do you think. I have used a radiator pressure tester on it and it holds pressure for 1 hour with no drop in pressure, radiator cap is also testing good. Why does this only happen occasionally, your opinion please. I am fully capable of replacing the head gaskets if necessary and have all the necessary tools to do so even though I am 73 and it will take a while. If I pull the heads I will have them done at the local automotive machine shop with a valve job also. Should I take tis time to also replace the optispark and water pump? This car will soon be my daily driver so it needs to be dependable it has 53,000 miles. I have always gotten knowledgeable help on this forum. If it wasn't for bad luck I would have no luck at all. Thanks for your time and please reply with your thoughts.
PS, what would be the best gasket set and head bolts to use, I am thinking Fel Pro for both.
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WOW no replies, guess I am on my own. I have a friend that owns a Combustion Leak Tester coming over tomorrow. That will tell me if there is a leaking head gasket and I will act accordingly. There is no coolant in the oil. I will go ahead and replace the Optispark at the same time along with the oil seal behind the water pump. I do have GM shop manuals to help me along. Thanks for looking.
Your description of symptoms could describe a coolant leak into the combustion chambers and that's either a bad head gasket or a cracked cylinder head. In that case, when combustion pressure is not present coolant will leak into the combustion chambers and, then combustion pressure is there, exhaust gases will leak into the cooling system. The pressure test and that fact that the characteristic is intermittant complicate the diagnosis a bit.

Most talented service shops can easily test your cooling system to see if you have a problem with head gaskets or heads. The test detects exhaust gas in the coolant.

If you going to DIY the repair, I'd diagnose first. If the diagnosis confirms a leak between combustion chambers and cooling system, pull the heads and have them pressure checked as well as checked for warpage. If the heads are ok, just replace the gaskets. If the heads are cracked or warped, repair or replace as necessary.

Fel Pro makes excellent gaskets. Only replace the head bolts if they are torque-to-yield fasteners.
I've seen bubbles in the radiator from exhaust gasses slipping past a gasket or head warpage, into the cooling system. The plugs may show rust or other indications of coolant getting in, too, as may excess water in the exhaust.

While I have not LT1, from what I've read, the newer Optispark not prone to water issues and new WP is good headwork.

I am not sure if your age/still wrenching makes me happy or sad; having a few more years to go. :w
The first thing to learn, are the head bolts torque to yield; if so, do not re-use them.

Borrowed from another site.

"From the book..."How to Rebuild Small-Block Chevy LT1/LT4 Engines" "Step-by-Step Rebuild to Factory Specifications. Covers 1992-1997 GM Cars and Trucks" by Mike Mavrigian on page 21....

"Since the SB2 engines [ie Small Block 2nd Generation, which the LT1/4 are] use TTY (torque-to-yield/torque-angle) cylinder head bolts, these original bolts will not be reused during final assembly."

Check your FSM to be absolutely certain.
Thanks Guys for the replies. My 1992 Corvette Factory Shop Manual says to torque to 65 foot pounds in three increments with no mention of torque angle so it must have just plain old standard head bolts. I will replace them if I pull the heads, I have always used ARP bolts and will use them here. Could you tell me how to tell the difference in the bolts? Wrenching at my age is not my job, I do it for my machines and have always been my own mechanic since my bicycle days before I had cars and motorcycles. Will test with my friends combustion leak analyzer tomorrow night and report my findings. I think I will also replace the Optispark and wires while I am there. I have compressor and air wrenches for disassembly and several high end Snap On torque wrenches for assembly. You now how it is just hate to take her apart you always have thet feeling that something might go wrong. I have built several small block engines in the past with no problems. Thanks again.
OK Guys, there is combustion gases in the coolant. As the Queen of Hearts would say "off with her heads". Luckily there is a first class cylinder head shop near me that has done work for me before with great results. Thanks again for the replies and holding my hand. I have coolant drained and fuel log off at this time, just taking a break.

Need some more help here. I can get to the passenger side head Ok but that darn ASR thingy is really in the way on the drivers side. Do I just unbolt it so it can move around a little? Or do I remove it completely? How the heck do I remove the cables going to it to remove it? PLEASE HELP ME HERE!

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