Hey guys, I have been searching the forums for answers to my questions, but I haven't been able to find any answers.

I have a 94 LT1 with about 186K on it. It just decided to run hot one day and I can't figure out the issue. I am sorry if this post is long, but I am trying to fill in as much information as possible since the issue is so perplexing to me.

Here's a little bit back story for you. I had a high idle issue with the car and I didn't want to drive it until I resolved that issue. While I was away on travel, I was asked by my BF if he could drive the car to work because he didn't have a way. I told him he could very reluctantly. He assured me that he would be careful with the car. He didn't have to go very far maybe 5 miles at the most. As far as I know, everything went fine. My roommate sent me a message asking if I wanted to change the oil in the car and I said sure. It needed it anyways. About 30 minutes later he is telling me that coolant is spilling out of the overflow tank and it is bubbling and gurgling! I knew something was wrong when he said that. My car hasn't had an issue like this before. He changed the oil in the car and it wasn't milky or frothy. Checked the coolant and it wasn't murky, but it was low on coolant so he added more to it.

Fast forward about 2 weeks and I return home. I fixed my high idle issue by adjusting the throttle cable and was happy with the way the car sounded. The power was right where it needed to be and everything seemed fine. I took it around the block and parked it back in the garage. A few minutes later, I start to hear the car bubbling and gurgling again. I didn't think it got that hot for the coolant to start to do that. I let it cool off for the night. I had to leave again and I decided that I was going to take the car back to a mechanic that I trusted. I hopped in the vette and my friend was following me in my truck and off we went. I noticed the temperature in the car slowly creeping up within the 1st hour of the trip. I thought that was odd, but it wasn't in the danger zone so I kept going. Going into the 2nd hour of the trip the temp got to around 223 and it wasn't cooling down at highway speeds. I pulled over at a gas station and popped the hood. The car was spewing coolant out of the overflow tank. I went in the store and bought 3 gallons of purified water and I had about a half of a gallon of coolant left in a jug i just bought. I let the car cool off for about 2 hours before i did anything to it. I put the water in and the coolant and started the car back up. The temp immediately started to rise again. I called a tow truck and towed it 2 hours back home. I couldn't go with it and I was sad. about a week later, I go back with a trailor and tow it myself to my mechanic 4 states away. I get it off of the trailor and he was impressed that it sounded so well. He even complimented me on it!

The next day we are testing out the cooling system on the car. He puts pressure on the cooling system and notices some little leaks. He tightens the screws and puts pressure back on the cooling system again. This time the engine locks up. not good. We pull all of the spark plugs out and there is water in the sparkplug of the # 2 cylinder. We key the engine and water is forced out. It wasn't a lot of water, but water still none the less. He told me it was a busted head gasket or a cracked head, but it didn't show the normal signs. We checked the oil again, no water. Checked the coolant again, no oil. Put the spark plugs back in and there was no smoke. Drove it down the road and there was no loss of performance. I am at a total loss here. I am hoping the gods of the corvette forum can help me with this issue.

I'm sorry for the wall of text, but any help would be appreciated.

 

IMHO, if you have coolant in a cylinder it can get there only one of three ways: 1) cracked head; 2) blown head gasket; or 3) voodoo curse. Unless you have offended a Haitian priest I would suspect one of the first two.

The fact that it is intermittent is a little baffling, but does not change the diagnosis. The fact that you are losing coolant not through external leaks or into the oil pan would indicate it's going out the tailpipe.

If it were me I'd throw a couple of cans of Bars-Leak (or the equivalent) in there and see what happens. You might get lucky.

 

Only way I know for water to get in the cylinder is head gasket or cracked head.. Hopefully just a gasket...WW

 

You're going to have to remove the heads. With that many miles, you might as well have a valve job done. At the very least replace the valve seals.

 

I suspect a blown headgasket as well....

If you pull the #2 spark plug again, I'd bet the white insulator has a nice green tint...

Here is a recent thread with pictures of a #2 headgasket failure.. Pix are about halfway down the page..

http://forums.corvetteforum.com/c4-t...hing-else.html

Note the close proximity of the water jacket to the cylinder.....

 

blown hg as others have said and possibly caused by an ineffective cooling system

the oem radiator in most of these cars is at the age it needs to be replaced due to scale build up. if tap water was EVER used it's all the more important.

 

Thanks for all of the information guys. I will try to get the engine pulled part soon. Would it be worth rebuilding the engine with that many miles on it? I know the guy helping me with the engine said that it might be best just to get a new engine all together.

what do you think?

 

Sounds like the guy doesn't want to be bothered with all the work associated with rebuilding, especially the machine work. It is quicker/easier to buy an engine that's already rebuilt and perform a simple swap. Basically it's a function of money and what you want to do with the car.

If you want to minimize costs, just pull the heads, have them pressure tested, fixed if cracked (they can weld them), resurfaced so they're flat, valve guides checked, etc, install new head gaskets, and be on your way for years to come. This approach will be fine if the engine was otherwise ok (ie no noises, not using oil, good oil pressure) and if the car is a daily driver / weekend cruiser.
- If you intend to use the car aggressively / want more power "while you're in there", then it's time to take a hard look at the checkbook and decide if you want a full stock rebuild (bearings, rings, lifters, etc), a stroker, etc.

 

Thanks for the info. The car is used for a daily driver with some fun thrown in every now and then. I'm not looking to throw stupid power into the car. I priced out a package from Ligenfelter for 10K to give me about 410 BHP / 385 lbs-ft of torque. I have also priced out a new engine (stock) for about 3K. I told the guy that I just wanted to replace the head gaskets and stuff, but he was saying that I would kill the bottom because the compression and stuff from the top would be too much. Does this sound right?

 

If the current compression is OK and the engine isn't burning oil, then replacing the head gaskets won't hurt the bottom end. I've seen the bottom end on these engines go well past 200K without problems.
$10K for 410HP?

 

I haven't checked the compression yet, but I haven't noticed it burning any oil.

It is a lot of money, but this is what it includes:

- Engine removal, inspection and disassembly
- Lingenfelter CNC ported & polished LT1 or LT4 cylinder heads
- Stainless steel 2.00" intake valves
- Stainless steel 1.56" exhaust valves
- Lingenfelter double valve springs, titanium retainers, 10 degree locks & seals
- Three angle valve job, checking of spring tensions and heights
- Lingenfelter designed Competition Cams hydraulic roller camshaft
- Ported and polished LT1 intake manifold
- Competition Cams High Tech stainless steel full roller rocker arms - 1.6:1 ratio
- 58 mm aluminum throttle body
- LPE engraved throttle body cover
- Professional installation, testing and tuning
- Stainless steel exhaust by Corsa
- Lingenfelter modified air box lid and K&N air filter
- Chassis dyno testing after installation
- LPE's 2 year / 24,000 mile warranty

 

10 k with labor doesnt seem all that for LPE to do all of the work, but I woud just pull the heads and freshen up the top end.

 

Thanks! I am thinking that as well. Everything else seems to be good with the engine. I think I caught the issue before it became an even bigger problem.

 

Tell him to put the crack pipe down It'll be fine.

Personally I think I'd find a new mechanic and that alone may add a few miles to the engine.

 

HAHAHAHA! I should!

Anyone know a good corvette mechanic in eastern NC?

 

........ Buy a new thermostat also ...................

 

I was planning on redoing the entire cooling system. The fins on my radiator have small cracks and there was nasty florida tap water put in it.

 

and this is probably what caused your issue.

griffen and ron davis make exact fit all aluminum radiators for these cars that are much better than oem.

as for the engine build there are a LOT of ways to make a 400+hp car and spend mmmm....around $5000 for the engine/intake combo. some of the big crate houses like jasper can turn out an 87+ roller cam motor with your choice of heads and cam. a nice 180cc set of heads and a comp 224/230 112LSA cam will drive about like stock, pull to low-mid 6's rpm wise if you use a miniram and still cost you around half of what lingenfelter quoted you.

MAKE SURE YOU HAVE ANY CUSTOM ENGINE DYNO TUNED WITH A NEW FUEL/TIMING MAP

had to really reinforce that last part since it's not hard to kill a motor with the wrong tune

 

Thanks for the info on those radiators. I'll research them and see which would be better for me.

I know about getting a proper tune. My friend race-tunes RX-7s and he has told me stories about people not having a proper tune and blowing seals.