I have a 2004 Suburban 5.3 which has an oil leak that drips on the exhaust header, but cannot see where it is coming from.
Changed valve cover gasket, then had to helicoil all four threaded openings for the valve cover bolts. Oil still leaks. I have a gut feeling it is a cracked head. Can a bad head gasket leak oil on the outer edge of the head and drip on the exhaust manifold?
Pretty bad leak too. When I stop at a red light smoke pours out the divers side of the hood.
It would not be the head or the head gasket for two reasons. First, the head gasket sits below the head and the exhaust. There's no way for it to be getting onto the exhaust manifolds. Secondly, there's no pressurized oil which goes through the head. All oil which gets to the top of the head comes through the push rods in the valve train.
I'd suggest either you didn't replace the gaskets on the valve covers correctly, or the cover itself is cracked, allowing the oil to flow through it ... if it is indeed coming from there. You also might not be seeing where the oil is coming from in the first place. It may not be coming from the valve cover or valve cover gasket at all, but some other place. You might want to thoroughly clean the area so you can find the leak. To do that, you might get some fluorescent dye, which you can track with a UV light. It can help you pinpoint exactly where the oil is coming from.
