Positive test for failed head gaskets ?
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Tuned
Joined: Dec 2010
Posts: 257
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Positive test for failed head gaskets ?
I suspect I may have failed head gaskets, but in reading a lot of posts here, it seems there are a lot of other reasons for coolant loss, puking degas bottle...etc.
So, before I spend a wad to replace head gaskets, I want to BE SURE that's the problem. What is the sure fire, definitive test for failed head gaskets ?
So, before I spend a wad to replace head gaskets, I want to BE SURE that's the problem. What is the sure fire, definitive test for failed head gaskets ?
Hotshot
Joined: Dec 2014
Posts: 17,838
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From: Jersey Shore
Pressure gauge reading the system is the simplest, foolproof way I know. We actually as a group should be collecting member info for a database.
Secondarily is using combustion test fluid (the type of diesels) but it has to be actively leaking, not just under high combustion pressure load.
Third is compression, but valves and rings can offset those numbers.
Secondarily is using combustion test fluid (the type of diesels) but it has to be actively leaking, not just under high combustion pressure load.
Third is compression, but valves and rings can offset those numbers.
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Tuned
Joined: Dec 2010
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Likes: 56
Thanks for the replies.
I suspect the leak is intermittent or only happens under certain conditions. Truck starts and runs just fine, but uses coolant at the rate of 1 gal in 600 miles or so of highway driving. If truck see any more than 20 psi boost the degas cap pukes coolant.
Upon cold start, my coolant pressure goes from zero to 16 psi within a couple of minutes.... today it reached 16 psi before the coolant temp even reached 90 degrees.............. then if I release the coolant pressure on a hot running engine, then re-tighten the cap, the coolant pressure creeps up slowly over the next five or ten minutes, to around 14-16 or so........ unless I get the boost over 20 psi, then it increases much more rapidly, and pukes coolant.
I don't see ANY evidence of white smoke under any conditions, so I think my coolant loss is from the blow off through the degas cap.
Any thoughts or help in diagnosing this is welcome. I'll do the head gaskets again if I have to, but don't want to over-react. Head gaskets and studs were done 6 years ago and I know for a fact that they did NOT use OEM gaskets at that time.
I suspect the leak is intermittent or only happens under certain conditions. Truck starts and runs just fine, but uses coolant at the rate of 1 gal in 600 miles or so of highway driving. If truck see any more than 20 psi boost the degas cap pukes coolant.
Upon cold start, my coolant pressure goes from zero to 16 psi within a couple of minutes.... today it reached 16 psi before the coolant temp even reached 90 degrees.............. then if I release the coolant pressure on a hot running engine, then re-tighten the cap, the coolant pressure creeps up slowly over the next five or ten minutes, to around 14-16 or so........ unless I get the boost over 20 psi, then it increases much more rapidly, and pukes coolant.
I don't see ANY evidence of white smoke under any conditions, so I think my coolant loss is from the blow off through the degas cap.
Any thoughts or help in diagnosing this is welcome. I'll do the head gaskets again if I have to, but don't want to over-react. Head gaskets and studs were done 6 years ago and I know for a fact that they did NOT use OEM gaskets at that time.
Laughing Gas
Joined: Feb 2016
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I don't know if this a) would work, or b) have a reasonable degree of accuracy. It's more a brainstorm for others more knowledgeable to comment on. Thought is if you could crank it with starter wire long enough to see if it builds pressure in coolant system. 16 psi at 90 F is getting it - I recall another member seeing 16 psi at 160 F with a confirmed gasket leak post-mortem. I would guess there's minimal exhaust backpressure during cranking but EBP could confirm. Anyway, random thought for Tuesday. Good luck with it.
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txuhaul
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Dec 22, 2016 10:31 PM
