90 ZR1: Oh crud, did I break it?

[GTOger]

Well, I wasn't able to get with "The Guy" at the shop today due to it being a holiday weekend and all. Same story at Corey Henderson's shop down in New Braunfels. So I'm going to have to try and exercise a little patience. The tech I talked to at Corvettes of Dallas (now Corvette World as of a couple weeks ago) says he's never broken down an LT5. He's never heard of one blowing a gasket like this. (Perfect... leave it to me).

He did mention that in order to get at the heads and pull the thing apart it could be necessary to pull the engine out of the car. That doesn't sound like any bit of fun. It sounds like a whole lot of money. Anybody have any words for me? I'm starting to get a little scared. A $10k engine rebuild is not within my realm of possibilities.

[Kevin]

Originally Posted by GTOger

Well, I wasn't able to get with "The Guy" at the shop today due to it being a holiday weekend and all. Same story at Corey Henderson's shop down in New Braunfels. So I'm going to have to try and exercise a little patience. The tech I talked to at Corvettes of Dallas (now Corvette World as of a couple weeks ago) says he's never broken down an LT5. He's never heard of one blowing a gasket like this. (Perfect... leave it to me).

He did mention that in order to get at the heads and pull the thing apart it could be necessary to pull the engine out of the car. That doesn't sound like any bit of fun. It sounds like a whole lot of money. Anybody have any words for me? I'm starting to get a little scared. A $10k engine rebuild is not within my realm of possibilities.

about the only thing i know of that will pop a head gasket on the LT5 is dexcool. did you check the map sensor?

[Z51JEFF]

Originally Posted by GTOger

A $10k engine rebuild is not within my realm of possibilities.

I wouldn't let my mind go too crazy just yet.When one of the injectors died in my 8000 ZR-1 I had what sounded like a rod knock I thought I was dead in the water.The knock turned out to be the flywheel-cam chains making a racket with the dead cylinder.Getting to the IH looks like a big job,it is a pain in the a$$ if you've never done it but get tons of pictures as the thing comes apart and its a piece of cake.The most valuable asset is right here,a bunch of guys that have done it.

[GTOger]

Originally Posted by Kevin

about the only thing i know of that will pop a head gasket on the LT5 is dexcool. did you check the map sensor?

I'll get out there and start looking. I'm not exactly sure *what* I'm looking for yet. I've never seen a "good" one, but based on some pretty good pics I saw earlier : I've got to think I could probably at least rule it out. It doesn't appear to be dexcool related.

Originally Posted by Aurora40

I don't know if I missed it, but why do you think the headgasket is shot?

Based on advice so far and my experience with old cars (60's muscle)... steam in the exhaust & burning glycol usually says "blown gasket". Of course, I'm just not used to thinking about an IH gasket so my head doesn't automatically go there. Yet.

Originally Posted by Z51JEFF

I wouldn't let my mind go too crazy just yet.When one of the injectors died in my 8000 ZR-1 I had what sounded like a rod knock I thought I was dead in the water.The knock turned out to be the flywheel-cam chains making a racket with the dead cylinder.Getting to the IH looks like a big job,it is a pain in the a$$ if you've never done it but get tons of pictures as the thing comes apart and its a piece of cake.The most valuable asset is right here,a bunch of guys that have done it.

That's a very diplomatic way of saying "calm down, dude." OK. I will. All my tools are at my office so I'll either find some usable implements I've forgotten about in the garage, or I'll pick up my tools tomorrow and dig in. Thanks for the motivational words.

[ittlfly]

I"ve got a Universal Block Tester Kit I bought to use on my old LT-1 after I thought I blew a head gasket. there is approx a half bottle left of the testing fluid. It has all the instructions on how to test (really simple) for a head gasket leaking, cracked block etc. A simple matter of watching the fluid turning form blue to yellow is a leak is present.

If you want the kit I"ll send it to you for nothing but I"d like to get the postage back. If your interested, drop me a PM...

[Kevin]

Originally Posted by GTOger

I'll get out there and start looking. I'm not exactly sure *what* I'm looking for yet. I've never seen a "good" one, but based on some pretty good pics I saw earlier : I've got to think I could probably at least rule it out. It doesn't appear to be dexcool related.
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you may have to pull the plenum to check the bottom side of it but that's an easy job.

[Ccmano]

Geezzz... you guys can scare the new guys half to death with this head gasket talk. While I agree that the stated symptoms may point in that direction there are other possible causes. There is a simple and quick way to check for a blown head gasket. Go down to your local Autozone or Kragen and rent a cooling system pressure tester. Hook it up, follow the directions (important) if it holds pressure you don't have a blown head gasket, if the pressure won't hold and there's no puddle of coolant under the car you have either a blown headgasket or a blown IH gasket. Once you've done that we'll talk.
H

[Aurora40]

I don't know if I missed it, but why do you think the headgasket is shot?

[A26B]

I'm with Bob here..... I think we may be doing the chicken little thing regarding the head gasket.. Should save the worst for last. Worry when needed. BIG difference in replacing injector housing gaskets & replacing head gaskets.

EZ check for head gasket leak. Remove the radiator cap (while cool of course) watch for bubbles in the coolant.

Injector housing bolts do get loose. Loose bolts could let coolant leak into the intake runners, causing miss, white smoke & sweet smell in the exhaust, along with low coolant in the overflow reservoir. Could leak into cyl's 1,2,3 or 4. Plugs would be white. Remove plugs only when engine is cool to prevent seizing. Do a little sniff test on each cylinder while the plug is out.

Don't stress. Pretty unlikely to blow a head gasket just tooling down the road......especially on Thanksgiving with your wife in the car!

[Jagdpanzer]

If it is a blown head gasket or injector housing gasket coolant leak do not attampt to crank the engine over before removing all of the spark plugs or you run the risk of greater damage if a cylinder is full of coolant. With the spark plugs removed crank it over to make sure the cylinders are clear. Then install the plugs and start it up with the cooling system pressure cap removed. If the head gasket is blown bad enough to cause to the running problems you have discribed you should see air bubbeling out of the coolant pressure tank.