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Discussion Starter · #1 ·
Heres the story
My car over heated and then bursted a frost plug on the Turbo. I didn't let it get to hot and I've replugged the hole and changed the sparkplugs, airfilter, coolant and oil. My car won't start! I did a compression test and I got 80-80-70-70. I know this is bad but it doesn't seem like a crack or blown headgasket because they're all pretty even.

I checked the spark, air, and gas and they're all good.

Does anyone have any thoughts?

Jimmy
 
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Dtodd55 said:
Heres the story
My car over heated and then bursted a frost plug on the Turbo. I didn't let it get to hot and I've replugged the hole and changed the sparkplugs, airfilter, coolant and oil. My car won't start! I did a compression test and I got 80-80-70-70. I know this is bad but it doesn't seem like a crack or blown headgasket because they're all pretty even.

I checked the spark, air, and gas and they're all good.

Does anyone have any thoughts?

Jimmy
I've seen headgaskets blown in every cylinder. I've also (personally) cracked the head in three cylinders.

If you overheated it bad enough to blow a freeze plug (I'm not aware of any on the turbo however, so you might be using incorrect terminology) then a blown headgasket/cracked head is likely.

A leakdown test would help right about now. You could have burned all 4 of your exhaust valves (On my cracked head, all 4 valves were burned and chipped as well) and you are losing compression out of the exhaust.

How long did it run overheating? Did your motor feel like it was starting to sieze? Overheated pistons swel, and can crack your ring lands from scraping on the cylinder walls, a cracked ring land would cause very low compression. You could have this, and a blown head gasket.

All this is apparent after a leakdown test.
 

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If you let it overheat and you say you burst a freeze plug, you may have just warped your head too, aluminum heads don't like to overheat, I warped mine somehow without the engine ever getting warm, my compression was 125, 125, 110, 108. Though I never had any trouble starting the engine.
 
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