I kind of have a odd issue, in the past when a HG had let go I would always have cooling issues after that but now I am experiencing some things that I am not used to with a blown head gasket. My cars temp runs great when I am at cruise and stay out of boost, the coolent looks good and the oil looks good, temps are great etc. When I go under boost I am getting excessive pressure in the cooling system, I always have water spit out of the overflow. I have had this happen many times and I figure if it's a head gasket then I would start having issues with cooling the car when I am out of boost but everything cherry. What do you guys think the chances are that the intake manifold gasket letting manifold pressure run into the coolent system? Any other ideas as to what is going on?

 

headgaskets do all sorts of things when they get pushed, that is one of them. It would be next to impossible for that to happen with an intake manifold leak, so my money is on a headgasket.

Easy way to check: take it to a shop that has a chemical 'exhaust gas' test or you can even pick up test strips at autoparts stores that you can use to test for carbon dioxide in the coolant. that will pretty much confirm that it's a head gasket (or I suppose it could be a cracked head/block, but unlikely)

 

I have seen this happen with blown headgaskets. Also seen it happen when someone puts on a headgasket backwards.

 

This has happened to me. I hurt it just enough to pressurize the cooling system under boost but nothing more. No visible cross contamination and car still made great power in and out of boost.

 

I did it on a 10.5:1 NA combo, it took near full throttle for it to pressurize the coolant system. So I just limped around for a month or so until I could afford the gaskets.

 

same thing happend to me, only mine was so bad it bubbled badley at idle lol

 

haha...not on mine. I dogged the shit out of it for a month before it finally spit them out completely.

It really wasn't that bad. Full on pass, temps went from 187-197 by the end of 4th

 

Just proof that blown headgasket does not always equal milkshake. Speaking of, I could go for a chocolate milkshake right now.

 

me too

 

My car did the same thing except back when i ran nitrous. Only when id spray would it charge the coolant system. The headgaskets were good but my heads were warped. Surfaced the heads, got new arp head bolts and gaskets and it was fine again.

 

what the fellow idiots said. i bet you that it blew rite here

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haha i blew mine there too

i wonder about that, i bet its weak hardware that causes that, it doesnt seem like its like some major detenation did that... mine looked the same

 

I have had the same symptoms occur from blown HGs. I have also had various degrees of milkshakes in the oil (depending on how large a path was blown for coolant to run into the lifter valley).

It just all depends on what part of the gasket failed.

 

I did that once running 18 psi and 32 degrees total timing on pump gas (operator error). It would just pressurize the coolant system under boost and wouldn't run hot. Eventually it blew it bad enough that coolant would leak out from between the head and the block... green river of coolant down the driveway... lol

 

Rest assured you got this.

 

sounds like the head is lifting as combustion chamber pressure rises .. like quicksilver said.. Some ARP's and a new gasket and you'll be good to go