Best way to rule out a blown head gasket?

gmc4flash

Original poster
Member
Mar 25, 2015
58
Ok so I put most of my comments in another thread regarding replacing the water pump in my Sons 2002 envoy. Thanks again to the helpful comments from all of you. I did about everything wrong in replacing it, (took everything off w/o disconnecting the clutch from the pump) I know... not the smartest nut in the tree. In any case I topped that off with handing my son the wrong screw to bolt the shroud back on... he promptly screwed it through the radiator... yeah I know. The top bolts are the same as the shroud bolts... only just enough longer.... in any case one epoxy repair later I think I have it leak free... still no weird noises and the temp is staying right at 210.(straight up) However after reading a bunch more wp threads, including one that talked about seeing bubbles in the coolant return reservoir... also another that mentioned to make sure I used the metal gm gasket ...

So I used the paper gasket that came with the new pump... is that a deal breaker?

Also I am seeing what looks like bubbles in my return tank... Should I go to the trouble and pull the plugs and do a compression check? Is that the best test?

Once again, much like before all advice is very much appreciated!
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
I wouldn't get all bent out of shape on it just yet. Sounds like you just completed the repairs so it's possible that the system is just purging air as it goes. Keep an eye on your coolant and oil. If one starts dropping and you see white gunk on your dipstick or white gunk in your coolant / on the radiator cap then you can suspect head gasket.


Just my opinion.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Like Mounce said. Give it some time before overthinking it. If it didn't overheat, I wouldn't worry about it. You can do a compression test if it makes you feel better. Costs nothing but your time.

Hey, we've all had :duh: moments. I could write a book about all of mine. That's how we learn.
 
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gmc4flash

Original poster
Member
Mar 25, 2015
58
So that makes lots of sense... I think I will drive it for the week before giving it back to my son. So on the hopfully very slight chance the headgasket is blown, how much risk to further damage if I drive it but watch the temps and shut it down if it starts going above norm... Also I just had the oil changed as well as the transfer case oil changed... It should be pretty obvious if the oil starts looking contaminated...
 

gmcman

Member
Dec 12, 2011
4,656
What did you fill the radiator back up with? Are you sure the leak is fixed? Chances are you would see something from where the leak was but my point is if you cannot sustain pressure the coolant can boil.

Back to the coolant, is it a 50/50 premix or did you mix the dexcool with water? Needs to be mixed to achieve the proper boiling point.

Other than that, I would perform a leak down test if any problems persist.
 

Texan

Member
Jan 14, 2014
622
We all have had bad moments, that is how we learn.
I think that you are probably seeing air being purged
out of the cooling system. I like the idea of you driving
it for a week and see what happens. Did you put new
Dex Cool antifreeze in it?
 

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