C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Blown head gasket??

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Old Sep 30, 2009 | 09:00 AM
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Default Blown head gasket??

Neighbor bought a C4 on craigslist and trying to help him out. The local shop claims it has a "cracked head gasket" but I want to see for myself.
The oil is clean and smells like oil, the coolant is full and smells like antifreeze, the car runs fine

How can I test for a blown head gasket??
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Old Sep 30, 2009 | 09:23 AM
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1. Compression test
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Old Sep 30, 2009 | 09:37 AM
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The shop says they did a compression test but if you have 1 cylinder low how do you determine head gasket versus rings or valves?

The C4 owner is not mechanically inclined at all,
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Old Sep 30, 2009 | 09:40 AM
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pressurize the cooling system
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Old Sep 30, 2009 | 09:43 AM
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Definitive test is to test for disolved exhaust gasses in the coolant.
Seems to be a special order for the kit from the standard autoparts stores.

What year is the car?
What is it doing to make anyone suspect there is a problem?
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Old Sep 30, 2009 | 09:44 AM
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Originally Posted by pr0zac
pressurize the cooling system
And keep the pressure on for a few minutes at least, watching for any sign of dropping. Also you could watch the flow of water in the radiator, if there's a lot of bubbles then compression is getting into the system.
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Old Sep 30, 2009 | 10:44 AM
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Originally Posted by pr0zac
pressurize the cooling system
Thats what I was thinking

Originally Posted by jaa1992

What year is the car?
What is it doing to make anyone suspect there is a problem?
Thats what I asked the owner

Originally Posted by Midnight 85
And keep the pressure on for a few minutes at least, watching for any sign of dropping. Also you could watch the flow of water in the radiator, if there's a lot of bubbles then compression is getting into the system.
I know we can get a pump to pressurize the coolant system to ?psi thru the radiator cap so if a leaking head gasket it will either push coolant outside the block or into the cylinder which we obviously don't want
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Old Sep 30, 2009 | 11:30 AM
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What was the result of the compression test?
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Old Sep 30, 2009 | 11:33 AM
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Go to your local NAPA store and buy a block tester kit. You put the blue fluid in the plastic tube. Put the tube in place of the rad cap and run the prewarmed up engine. If the fluid turns green or yellow, there is exhaust gases in the coolent. It may take a couple of minutes, but this is the test I use.
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Old Sep 30, 2009 | 11:51 AM
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Originally Posted by cumbercr
What was the result of the compression test?
You know how a shop is, they don't tell you #1@156, #2@165 etc

Originally Posted by Paul Ruggeri
Go to your local NAPA store and buy a block tester kit. You put the blue fluid in the plastic tube. Put the tube in place of the rad cap and run the prewarmed up engine. If the fluid turns green or yellow, there is exhaust gases in the coolent. It may take a couple of minutes, but this is the test I use.
This sounds like the diffinitive answer

It's amazing how you can learn anything you need on the internet
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Old Sep 30, 2009 | 12:33 PM
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Originally Posted by Paul Ruggeri
Go to your local NAPA store and buy a block tester kit. You put the blue fluid in the plastic tube. Put the tube in place of the rad cap and run the prewarmed up engine. If the fluid turns green or yellow, there is exhaust gases in the coolent. It may take a couple of minutes, but this is the test I use.
only way to do it. Pressure testing the cooling system only tells you if you have a cooling system leak (15 psi). Combustion pressures are 1,000's of PSI. Get the NAPA block tester (balkamp 700-1006). It's very easy to use.
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