Cometic Head Gasket Leak!!!

[Fastair6]

Pulled the motor over the winter due to a blown stock head gasket on #2 cylinder. Decided to add a roller cam and ported heads. I must have talked to a dozen people on head gasket advice and finally settled on Cometic.

I was warned to use copper spray on the outside and in between the layers which i did including new APR bolts.

I now have a leak on #3 cylinder between the layers. Retouqued the heads and had no effect on the leak. Did i improperly prep the gaskets? The only thing i didn't do was heat the cylinder heads and block when i initially torqued the heads. Talked to Julio and went 20, 40, 60, 85 on the torque for the bolts.

The toon is good with zero knock at 25 pounds on Alky. I guess something must have been off. I'll know more when the motor comes back out.

Any advice on head gasket choice would be greatly appreciated.

Thanks.

 

[GO FAST]

I always use radiator seal / GM tablets for xtra insurance.

 

[V6RACER]

When you were spraying copper spray you may have gotten something between the layers.. sometimes that spray comes out in small globs. Install dry and GM Coolant tabs if needed.

 

[Razor]

Did it leak after you installed it or after you ran it?

 

[Fastair6]

Razor thanks for asking. It leaked after i ran it. I've put about 600 miles on it since the motor went back in. This was also just a head swap. The block didn't go to the machine shop. The deck was checked with a known good straight edge to make sure it wasn't warped. Maybe the the block surface was not smooth enough for the cometics.

I also did not add any GM tabs or radiator seal as was suggested by GO FAST and V6 RACER.

Provided i didn't crack anything, do you have a suggestion for a replacement head gasket?

Thanks for the help.

 

[Razor]

Guess you need to pull the head and see what happened then make decisions

Gasket typically isn't the problem

seal tabs won't work if heads lifted creating the problem

 

[gnfanatic]

were the heads machined for cometics????? They need to have the right surface for cometics. I never had a leak and they been on the car for at least 4 years.

 

[SNOWBIRD]

Befor taking heads apart pick up some tabs at the dealer and crush 3 in a plastic baggy and pour powder into radiator ....drive car for a couple of days.O you can take 2 tylanol if it doesnt stop the leak

 

[SNOWBIRD]

I see no mention of thread sealer on your ARP head bolts?

 

[89ICBM]

Hi! Fastair6,

I would like to know what your symptoms are? Are you boiling water out of thr radiator? Is there white steam or water blowing out of the exhaust or is there a ticking like a valve noise? Just curious,hope you don't mind.

 

[Fastair6]

I really appreciate all of the responses and suggestions.

After digging a little deeper i'm not leaking water or getting anything in the cooling system or oil. It's losing compression. More specifically it's pushing oil from between the head gasket and the block and from between the layers.

I took Julio's suggestion and used locktite on the head bolts when the motor went together. I added the gm tabs after they were suggested on this thread hoping it was coolant related. I have had no change.

It looks like i'll have to pull the motor back out. The heads were surfaced when they were redone, but the block wasn't. I think this is probably the problem. The block didn't have the correct surface required for the cometics.

I'll send an update when i get it apart.

Thanks.

Jer

 

[19TTA89]

I really appreciate all of the responses and suggestions.

After digging a little deeper i'm not leaking water or getting anything in the cooling system or oil. It's losing compression. More specifically it's pushing oil from between the head gasket and the block and from between the layers.

I took Julio's suggestion and used locktite on the head bolts when the motor went together. I added the gm tabs after they were suggested on this thread hoping it was coolant related. I have had no change.

It looks like i'll have to pull the motor back out. The heads were surfaced when they were redone, but the block wasn't. I think this is probably the problem. The block didn't have the correct surface required for the cometics.

I'll send an update when i get it apart.

Thanks.

Jer

Do you hear the leak under the hood?Or just leaking oil that appears to be running off the gasket?

It is Highly Unlikely you are leaking oil through a Cometic(Unless you actually hear the Compression escaping through the gasket)You have a oil leak,But it Isnt coming through the layers.

Check the back of the Intake first,That is usually where it comes from,I thought the same thing years ago with Cometics...It finally took my Putting that Dye in the oil and looking with special glasses...Sure enough...right to the back of the Intake...It was just running down,Traveling along the gasket edge,And dropping off around mid point onto the Header.

There is no oil under pressure there,If the Compression could push the oil through the gasket,Be sure it would follow right behind it and you would think you had the exhaust leak of the century.Dont pull the head for no reaso

 

[turbo nasty]

Mybe I missed it...kinda breezed through the posts,

Did you try a retorque?

 

[Fastair6]

Hey guy's,

Well I pulled the heads and found a 1/4" wide combustion mark from the loss of compression directly between the lower head bolts on the #3 cylinder. It also was starting to do the same thing on #4 cylinder only it hadn't completly reached the outer layer of the fire ring.

One thing I didn't mention is that I have a Hemco plenum. I have heard that they cause a lean condition on cylinders 3 and 4 especially at higher boost levels. Looks like this might have happened here. I was between 25 and 27 pounds right before this started. Looks like I'll be moving over to a RJC plate instead.

Thanks for all the help and suggetions. You guys rock!

Jer