Blown head gasket ?

[amani260]

Hi everyone, been a while since I have worked on the GMC.
Replaced heads , cam , lifters a while back then got sidetracked for a while before really testing it out. Anyway, it starts right up and runs little rough. I noticed bubbling in coolant with radiator cap off . Drained oil and it definitely has coolant in it. So Im trying to take my time before I just tear everything apart. Is there a way of determining , if it is a blown head gasket, which cylinder it is in without taking head off? Mainly meaning, if only one side is blown, why do both sides. I removed spark plugs but they all look same , didnt notice one looking cleaner or different color. Any thoughts would be appreciated, thanks

 

[Ricko1966]

Did it have coolant in the oil problems before the work? When did the problem start?

 

[amani260]

Well I dont think it was getting coolant in oil before I replaced heads and cam , but honestly its been quite a while since Ive worked on it, ( had some medical issues). I was secretly hoping it might be intake manifold leak instead of head gasket, just trying to pin it down before I go crazy replacing everything.

 

[amani260]

The bubbling in the radiator is what made me think head gasket

 

[Ricko1966]

Do a cooling system pressure test. If you don't have,don't want,can't afford a pressure tester,let me know. I do have a workaround. Anyway pressure test no spark plugs,dist hot lead disconnected,leave pressure on an hour or so,then crank the engine watch for water to shoot out of a plug hole.Yes cylinder head is coming off. No the drain the oil leave the plug out,wait for it to quit dripping,then wait some more. Okay,pressure test again,do you get a leak out of the drain plug?

 

[amani260]

I have a tester, somewhere. If I can find it I will give it a try, thank you

 

[amani260]

Ok, found the tester, ( my brother had it). Hooked it up, pumped up to 15 lbs, been sitting for about 3 hours, barely gone down a pound, thinking I need to wait til its gone down a good bit to get enough in cylinder to blow out . May give it overnight.

 

[Edelbrock]

If it lost 1 lb in 3 hours, I would say your probably OK. I mean, ambient temperature changes could cause a 1 pound drop, or maybe the seal on the tester is not 100% absolutely perfect.

Also, I would double check the intake manifold gaskets. Maybe re-torque it and see if any of the bolts are loose.

 

[Ricko1966]

Ok, found the tester, ( my brother had it). Hooked it up, pumped up to 15 lbs, been sitting for about 3 hours, barely gone down a pound, thinking I need to wait til its gone down a good bit to get enough in cylinder to blow out . May give it overnight.

Not a bad plan.

 

[amani260]

I know its getting into oil somewhere, might not be big leak , but Id like to figure out where, Im gettin too old to be climbing over into that engine bay more times than needed.

 

[Ricko1966]

If you have to wait 29.37 hours to verify it's leaking into a cylinder,but you verify the problem in 29.37 hours then you've done the right thing. There is no harm in doing it that way. I would say I would not wait until all pressure was gone though. I would be afraid of bleeding off all pressure and giving enough time for the cylinder to dry out. A last thought,are you sure the water in your oil is not leftover from when you pulled the manifold? Are you using the same manifold as before?

 

[amani260]

I dont think it is, but I cant swear to it, been a while since work was done.
I will check it in morning before work, see where its at. Thanks for responses