Well installed the new heads with a Cometic .040 head gasket, and yes I made sure the block surface was thoroughly cleaned. The head gasket was installed dry as Kjones from SDPC said it should be installed. Installed ARP head bolts.

I spent over 3hrs cleaning the bolt holes. Actually used a straw attached to a wet/dry vacuum with this micro attachment and sucked out majority of the coolant from each hole. Then ran paper towels down each one till it came up dry.

Installed the heads, torques the bolts to 30, then 50, then final run of 70ft lbs. And yes I used the ARP Moly lube as they recommend. I even went back a week later and retorqued the bolts to make sure its good.

But what Im seeing is that there seems to be a mixture of oil/coolant seeping from the head/block area, right from the headgasket basically. Basically if you run your finger near the gasket area from under the headers you will come up with oil on your fingers. If you look at the craddle, you will see its wet with like oil and coolant. Sometimes when Im stopped at a light it will smoke from the hood vents slightly for about 5secs, I guess when a drop or something gets on the header or too close to it. I took the car to a Corvette tech at the dealer (good fellow) and his buddy who is a performance tech said that .040 cometic gasket needs to go. He will redo the job for me but he does not want to install the cometic back even if we spray it down with copper sealant. He wants to reinstall it with a new stock GM .052 MLS gasket. Now at this point I dont care I just want it to stop leaking/seeping. But just wondering why is it leaking?

Sometimes I sit here think, what if I didnt thoroughly clean a bolt hole, and hydrolocked it and cracked it? Would it do what Im seeking or would it be much worse like car would barely run, coolant would be spewing out and stuff? I mean I know I ran a paper towel down each hole. And also forgot to mention the car runs fine. I can gun it and it hauls! But if Im on the freeway and got it set to cruise at 75, it will hesistate during the cruise for split seconds, we talking the most ever so soft hesitation, but I can feel it from the seat and know that it just stumpled. I got a feeling oil/coolant is getting into the cylinder and causing that when it combusts.

Just looking for answers or suggestions.

Dixit

 

Is it possible the gaskets are on backwards? How are the tabs lined up? It seems like you did a good job cleaning and Prep. Most people only get a coolant leak, not both coolant/oil, at least what i read. I would deinately have the heads pulled and see what is going on. I'm on my second set of Cometics now (.043 and .027), put them on dry as well and been lucky enough to not have them leak. Hope you get fixed soon!

Dan

 

Was told there is no front or back on the head gaskets. They are identical either way and I verified this.

Dixit

 

Yes that's true, but the coolant holes match up differently. On the passenger side the tab should be sticking out closer to the firewall. On the driver side it should be closer to the radiator. If they are on the other way you will be blocking a set of coolant holes and you will get leaking.

 

I always use spray copper sealant on the cometics. Never had one leak. There is a front/back to the gaskets also, although its not marked. There is 2 coolant passages to the rear of the block that the gasket has matching holes to. One head gasket will be installed right side up, and the other will be upsidedown on the opposite side, either gasket can be used on either side as long as those coolant passages line up.

 

Glad I read threads like this, I will be installing my .040" soon and DO NOT want any issues. Thanks for sharing your experience.

Charlie

 

I use the copper spray and no leaks either. With head studs lining everything up with coolant holes is easy.

 

I have had no probs with mine yet. Didnt notice the coolant passages though. Maybe I got lucky but I put the gaskets on both sides and they matched everything all the time. How long did you have them on before they leaked? GOD NO!!!!!!

 

 

im curious how long you had them on for before they started to leak. If it was leakng within 50 miles im good but if not I could be in trouble...

 

Well son of a ...... No one told me about the coolant passages are different. I was told that they are identical and dont matter what side you put them. When I put them on I verified the coolant passages and they looked good. I had them on and within a few days I noticed the coolant was leaking from it. Well guess we will find out in a few days to see if they were installed correctly.

Dixit

 

did you look in the thread I started? Shows a pic of daves motor torn down and the extra coolant pasages in the back. Did it run hot?

 

Havent seen the thread you are referring to. The engine never runs hot. I have a 160 Tstat in there and my temps are still at the same 178F area while driving and my oil temp is in the range as before.

Dixit

 

same as mine I run the same stat and see 174-180 so maybe you did install them right. I meen you would see the metal showing up through the gasket if you put them on backwards. well if you pull your heads let me know what you see. also look at your rivets on the head gaskets. My drivers side has a smaller diameter of the gold rivet showing than the drivers.

 

ive installed my .040" cometics dry twice now. In fact, the second time I was WOT less then 2 miles after putting the heads back on. Never a leak.

Dave

 

I used the cometic on AFR's dry, and had a small leak until I started it and got some heat into it, now its fine.

 

i installed my .045 cometics dry with my AFR's and I have had no problems yet. I was confused about the water passages to the point when that I thought I had the wrong gaskets sent to me until I figured out one had to be "backwards" or something to line up the water passages correctly....I do not recall. I have also read alot about cometics and studs used in conjunction creating leaking issues for what it is worth.

 

Are you certain they were unused? I had .045gaskets installed with no issues.

 

I used .040 Cometic Gaskets on my 408 and one gasket needed to be installed upside down. I used GM head bolts and have no issues.