Oil Leak Part 2

[Sloan66]

I have been chasing an oil leak on my 71 307. Initially it was the oil sending unit and a small leak on intake. Those issues have been addressed and confirmed not to be leaking. Valve covers are dry as well. I still have a leak from what appears to be where the head meets th block on the driver side, leak follows the bell housing and down onto the exhaust.

Any ideas where the oil is coming from? Is the a plug on back of head? could it be leaking between head and block? It runs very well, oil is clear so I do not believe I have a bad head gasket. any help would be appreciated.

[Old Truck Man]

Valve cover gasket is the likely culprit. I like cast aluminum valve covers because their very rigid and seal very well. However stock steel valve covers can be effective. I make sure the covers are straight. they are sometimes damaged by being over tightened. I use a cork gasket and coat both sides of the gasket with RTV silicone. place them on the head and just barely snug down the fasteners. wait 24 hours until the silicone hardens before tighting the bolts properly. If you tighten down before the silicone cures it just squeezes out. why bother putting any on if your are just gonna squeeze it out. and just as much squeezes to the inside of the engine as outside. silicone floating around inside an engine is not desirable.

[cool68]

I have been trying to track down a leak on front of a 350 and people that reply say to just clean area real good and watch for source. others have said to clean area and use spray on foot powder. have not heard if anyone has ever used a liquid leak detector put into engine and use a black light to find leak origin. I never use all cork valve cover gaskets, harden and fail - hard to remove. a blend of rubber and cork or a set with a thin metal wafer between layers. sealer is not meant to set up for a long period of time before tightening down. read label on sealer.

[cleszkie]

Could be a leak between the oil pressure line bung and the oil pressure line. the bung is located on the rear top of engine block on flat surface between intake manifold and engine block. if this leaks, oil will drip down belhousing as you describe. You should not be leaking out of head unless you have a ton of blow-by and a crapped out head gasket.