Is there a trick to keep the manifold from leaking. I just put a new intake manifold on and i have coolant leaking from some of the bolts. Is there a trick to prevent this. Should i put silicone on the bolts?
I had this happen recently on my Chevelle 350 rebuild. I put on a Edelbrock performer intake and first it leaked out the back when pouring water in the radiator. Discovered loose intake bolts, retightened by hand and that seemed to take care of the leak. Once we got the engine started and it started to heat up, water started to leak out the top around the bolts. However once the engine got hot, the leaking slowed way down. After letting the engine cool and going over the intake bolts again, it seemed to fix the problem. apparently you need alot more torque on the aftermarket intakes than what's called out in the manuals for a stock intake.
On some heads some of the intake bolts holes enter the water passage and can seep water up around the bolt without leaking internally into the motor. This is most common on the two end bolts at each corner of the intake. These bolst should be coated with something to keep this from hapening. Silicone will work, ARP thread sealer works better. Do not just overtork the bolts This can warp or crack the intake.
If your worried about an internal leak check the oil for white streaks or a higher level.
I was planning on using either Permatex liquid teflon sealant on all those bolts, what did you use? Also curious...I know you didn't mention any leaks at the front and rear but did you use the rubber seals or just silicone?
I will soon be adjusting my rockers then getting the manifold on. Have not yet ruled out using the seals. I was told no adhesive below the seals, only above. With head and manifold gaskets on I have 3/32" clearance. The rubber seal is 1/16" so I will need a small bead of silicone regardless. Sorry to hijack but figured it was somewhat related.