Bad head gasket?

[hihok9]

I have the chance to look at a 91 motor that after running for about 20 min starts to push bubbles into the radiator, guy says it's the head gasket... does this sound familiar to anyone, and how can I check to make sure it isn't something worse like a crack... what else should I look for, check, etc... thanks!

Hiho

[GOLDCYLON]

Originally Posted by hihok9

I have the chance to look at a 91 motor that after running for about 20 min starts to push bubbles into the radiator, guy says it's the head gasket... does this sound familiar to anyone, and how can I check to make sure it isn't something worse like a crack... what else should I look for, check, etc... thanks!

Hiho

Without a tear down into the heads its hard to tell. You can drop the oil to look for the shaving cream appearance in the mixture. Depending on the leak it could be weeping into the galley and could be coming out of the rear drain tube. The exhaust also and offer clue which will collorarate the head gasket. A crack however not really until your start the tear down. GC

[bans25]

Originally Posted by hihok9

I have the chance to look at a 91 motor that after running for about 20 min starts to push bubbles into the radiator, guy says it's the head gasket... does this sound familiar to anyone, and how can I check to make sure it isn't something worse like a crack... what else should I look for, check, etc... thanks!

Hiho

The one down the cape? I was thinking of going to look at that one myself.. I will hold off if you are interested

[hihok9]

That's it. I might drop it in my next project.

[bans25]

Originally Posted by hihok9

That's it. I might drop it in my next project.

I think I talked to that guy selling the motor 5-6 years ago (maybe longer) when he was doing the install. I was thinking of getting it for a project as well but no real project on the horizon.. good price if it is just a gasket needed..

Did you buy all those other parts that were in Boston??

[hihok9]

Hi Bill,

Nope, I saw those parts but passed on them.

[Paul Workman]

Originally Posted by GOLDCYLON

Without a tear down into the heads its hard to tell. You can drop the oil to look for the shaving cream appearance in the mixture. Depending on the leak it could be weeping into the galley and could be coming out of the rear drain tube. The exhaust also and offer clue which will collorarate the head gasket. A crack however not really until your start the tear down. GC

I've had experience with a gasket leak resulting in water getting into the oil (chocolate milk), but if he's getting bubbles in the coolant, wouldn't a compression test possibly indicate a leak? Methinks that would be the nastier of the two as coolant would likely be filling the cylinder when the engine was not running. I'd wanna do a compression test.

Speaking of leaks, Marc Haibeck did a piece a while back on the effects of Dexcool on our gaskets. He showed me one of the gaskets exposed to Dex and the errosion of the gasket anywhere coolant touched it was quite evident. Ye 'ol GREEN glycol stuff is the one to use (Napa for one) is what I took away.

Well, here's a question for anybody... Assuming a new gasket that is compatable with Dex, is there any OTHER components that have to be considered if using the new Dexcool (orange) stuff?? (I'm wondering about the TB gasket and the coolant pipe gaskets. ARE JERRY'S NEW HEAD GASKETS DEXCOOL COMPATIBLE I wonder (out loud)?

P.

[GOLDCYLON]

I dunno stick with the green stuff and why take the chance to any of the other components? As to a compression check yes that one of the many things the potential buyer could due as he goes through the analysis process. My suggestions were basic troubleshooting suggestion before getting jiggy with it. Moisture on the plugs as well etc. GC

[Hib Halverson]

If you mean, when you say, "pushing bubbles into the radiator", that when you take off the cap, start the engine, then look into the high fill bottle, after the engine runs a while you see some bubbles in the coolant flow that enters the tank near the cap, if the bubbles are small, continue for a short period and don't smell like exhaust, I'd say that's normal.

However, if you suspect a head gasket problem, I'd run a cooling system pressure check, that will find a head gasket leak from the cooling passages to the bores.

You can also run a cylinder leakage test and find a head gasket issue.

If it's really bad you even can find it with a compression test.

Also, if you find someone with a borescope you may be able to even "see" head gasket problem.

If you have a head gasket leak from coolant into the oil, you have the baby s&%t looking creamy stuff on the dip stick.

[VetteVet]

A combustion leak tester would tell you for sure.

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