I just put this new manifold on about 3 weeks ago. It has been leaking antifreeze almost from the get go, but couldn't find the leak. Today the car almost overheated, so I popped the hood to see the very front bolt on my intake near the #1 cylinder leaking out boiling antifreeze. Does this DEFINITELY mean a blown gasket? I retightened the bolts about a week ago. Thanks.

 

Did you use the correct intake bolts for a sbc? The bolts at ends will bottom out if there too long and won't compress the gasket enough to seal. If thats not the problem remove the bolt and load the threads with silicone ,you might get lucky.

 

You need to use a sealant on the bolt threads, like Loctite PST or Pro-Lock Sealant. Clean the threads, apply the sealant, and retorque to 30 ft/lb.

 

The bolts are the right ones for a SBC, and I did use a sealant on the threads. If I pull only the one that is leaking out and redo it, will I need new gaskets anyways? Thanks.

 

I'd redo both sides, it's not worth going through all the trouble and just doing one,I wouldnt trust the side that is'nt leaking to reseal again.I would use new gaskets also. Just take your time and clean everything thoroughly. I'd even tap the holes to make sure theres no debris stuck inside and use a heat gun to dry everything up,and break cleaner to get rid of any oil residue.

 

Well, I just put the pressure tester on the system and I saw a stream of coolant coming out between the manifold and the head, so the gasket is definitely shot. Not sure how it was boiling out of the bolt hole earlier though. What could have possibly caused the gasket to go like this? I used sealant on the threads, I'm not using the front and rear intake gaskets (using RTV instead of the "china walls"), and I retorqued the bolts about a week ago. Like I said earlier, the gaskets are only about 3 weeks old. Thanks for all the replies.