I have a 95 f150 with a 5.0 302. motor was put in 14,000 miles ago and has about 90,000 on it. I was taking the valve covers off (have to take upper intake manifold off too) and noticed there was oil in the intake manifold. it was a thin coating. I didn't notice it until I put it on the front of my truck and it started leaking onto the truck. I had the motor put in by a local shop and it did not have a pcv filter (I replaced it as well and found that out). Could that be the cause of the oil or would it be from the piston rings? And if it is the piston rings, can someone give me a ballpark figure of what it would cost to have the motor rebuilt? Or would it be better to find a used motor from a salvage yard and have it put in?
(I included a pic showing the oil when I held the manifold on to make sure it would clear the new valve covers)

 

Normal, replace the gaskets and ride.

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