Installed new heads back in December, I had a master mechanic helping me put the heads on. I used the MLS gaskets, and he said to just torque all head bolts down to 75ft lbs (not including the top 5 of course). Now it appears I am SLOWLY leaking coolant into the engine, because when I look into the radiator I can't see any coolant when we had topped it off to begin with. No leaks on the ground that I can see. Its been running good for about 3 months like this, but of course I need to fix it.

Question is, how much more do I need to torque down the bolts? Not sure since i've already torqued them to 75 ft lbs. How much more? 90 degrees? Also do you think the gaskets will still be fine? New bolts?

TIA,
Adrian

 

since you're diving in there anyway, i would get new bolts and gaskets...follow the instructions for a head swap on ls1howto.com - you'll find the proper way to torque down the head bolts

 

Some master mechanic. For stock head bolt I believe it 75 ft lbs, the 90 degrees, then 90 degrees again.

 

well, I actually think its alright, cause I just changed my oil, and its as normal as could be. When i did the cam/heads/ swap I also punched a hole in my radiator, and JB welded it. So its possible that its leaking ever so slowly. And the more I think about it, the more that makes sense cause i haven't seen any of the usual signs of a head gasket leak.
Anything else I should look for?

Thanks for the thoughts!
Adrian

 

It's 20 or 22 ft-#'s then 90 degrees & 90 again. I measured the torque after the second 90 degree turn & all the (main) bolts were in the 100 ft-# range. Would think that 75 ft-#s could be close enough (on a naturally aspirated engine). The main thing is that the bolts stretch. If there is a severe enough leak, the oil will look milky &/or there will be steam coming from your valve cover when the fill cap is removed. Can also look @ the PCV valve for a milky coating.

 

Sounds like your "Master Mechanic" needs to read the forums on LS1Tech.com and read the articles on LS1HowTo.com. The stock head bolts are designed to be stretched using the degree turn method and not the torque method like older engines.

 

You are trying to obtain the proper preload in the bolt. Yours is not correct. I think it may be a problem waiting to happen. I just had coolant dump into my Pontiac 3.1 when the lower intake gasket let go, the inside of the motor that was previously pristine looks like it came out of a swamp. I would strongly consider a "re-do" using the service manual methods and procedures.