Possible Head Gasket Issue

[Shawn]

Well, my luck on this nicely built 383 ran out. Starting to have some bubbles come through the coolant bottle and now got slight white smoke at idle. I tried the blue dye and tube head gasket test after removing a good amount of coolant but the antifreeze kept coming into the test tube and could never get a good reading on the blue test fluid. Besides a compression test, any other ideas to track down which side it might be on? I'll probably do both head gaskets just to be safe. Really didn't want to tear this engine down. Will be checking cylinder head surface for warping and cracks. Also, was thinking about using this product to look for any cracks on the block / heads. Any other suggestions?

Blue test fluid and test tube:


View attachment headgasket.mp4

 

[Wes Harden]

Aftermarket heads or factory?

 

[ZooMad75]

The blue test fluid usually worked for me at the dealership. But the late model stuff would have the pressure cap on a reservoir and not on the radiator. I know the engine has to be up to temp for the test kit to work.

If you are seeing white smoke I’d at least pull the plugs and see if any are super clean from coolant steam cleaning the combustion chamber. Might narrow it down to one side without pulling both heads.

Another way to go is to put a pressure tester on the cooling system. I’d also do this with the engine warmed up as any issues may close up when it’s cold. Push it up to 15 psi and see if it holds. If it’s really bad it may start dropping right away or never allow you to get the pressure up that high. If it’s a small leak you could have it bleeding off a little over 20-30 minutes. Obviously a sealed system shouldn’t drop any over 20-30 minutes so if it drops any it’s time to make sure there are no external leaks and if there isn’t any it’s probably internal.

Unfortunately it won’t tell you which side to look at.

Though if you want to go through the process of a leak down test and you have the equipment to do it that should nail it down to the specific cylinder. If you see bubbles coming out of the cooling system with pressure on one cylinder it’s probably your source.

 

[Shawn]

Aftermarket heads or factory?

Aftermarket GM alum heads. Not sure exactly what specs they are but they are alum for sure with angled plugs. I don't think its anything too special. Would rather have some AFRs.

The blue test fluid usually worked for me at the dealership. But the late model stuff would have the pressure cap on a reservoir and not on the radiator. I know the engine has to be up to temp for the test kit to work.

If you are seeing white smoke I’d at least pull the plugs and see if any are super clean from coolant steam cleaning the combustion chamber. Might narrow it down to one side without pulling both heads.

Another way to go is to put a pressure tester on the cooling system. I’d also do this with the engine warmed up as any issues may close up when it’s cold. Push it up to 15 psi and see if it holds. If it’s really bad it may start dropping right away or never allow you to get the pressure up that high. If it’s a small leak you could have it bleeding off a little over 20-30 minutes. Obviously a sealed system shouldn’t drop any over 20-30 minutes so if it drops any it’s time to make sure there are no external leaks and if there isn’t any it’s probably internal.

Unfortunately it won’t tell you which side to look at.

Though if you want to go through the process of a leak down test and you have the equipment to do it that should nail it down to the specific cylinder. If you see bubbles coming out of the cooling system with pressure on one cylinder it’s probably your source.

Great info as usual! Thanks! I was going to pull the plugs anyway and do a compression test. I do have a radiator pressure tester kit. I know it holds pressure over night. When I took off the cap yesterday, some fluid shot out and it was off for 24 hours. I don't have a leak down kit but thought about buying one.

If I do replace gaskets, I was thinking of going with the better FelPro kit. I also looked at their MLS gaskets which are more $$$ and some people were complaining about leaks with those.

 

[ZooMad75]

I’ve never had a problem with Fel-pro head gaskets on anything I’ve done. I don’t know if I’d go to the level of expense to put mls versions on. At least until you know the root cause of the problem. If the gasket was the issue then going up to mls should help. If it’s something else like a cracked head it wouldn’t make a difference what gasket you had.

 

[Wes Harden]

I was curious, be cause I know some of the gen 1 gm iron heads are prone to cracking. Know nada about aluminum heads. Check your oil for contamination soonish.
I also have never had a fel pro blue head gasket fail, with out an over heat warping. You'll want to measure your current head gasket thickness to get the same

 

[Shawn]

I’ve never had a problem with Fel-pro head gaskets on anything I’ve done. I don’t know if I’d go to the level of expense to put mls versions on. At least until you know the root cause of the problem. If the gasket was the issue then going up to mls should help. If it’s something else like a cracked head it wouldn’t make a difference what gasket you had.

I've had good luck too with Fel-pro headgaskets. I was only looking at the more expensive MLS head gaskets since I prefer MLS on high compression and forced induction vehicles. From the reviews, some said people they tried the FP MLS and had issues with coolant leaking and went back to the standard blue FP gasket. Kind of interesting since you would expect the MLS to be better since you are paying more money but thats not always the case.

I was curious, be cause I know some of the gen 1 gm iron heads are prone to cracking. Know nada about aluminum heads. Check your oil for contamination soonish.
I also have never had a fel pro blue head gasket fail, with out an over heat warping. You'll want to measure your current head gasket thickness to get the same

Good to know on the GM iron heads and makes sense on the crack. Thats why I was thinking of magnafluxing block and heads just to be sure. Looks like they don't make that magnaflux kit no longer. I will have a better idea on what these heads are after taking them off. You can tell someone spent some money on this engine. Alum heads, nice alum intake, roller cam, roller lifters, roller rockers, thicker blue Moroso valve cover gaskets, alum valve covers, MSD distributor, MSD inginition. I think it has forged components but not 100% sure.