I have a 1987 f150 4X4 I6. I am getting an oil leak somewhere down the driver side of the engine. Had the valve cover gasket replaced because it was leaking too and that got rid of most of the leak but there is still some oil coming from somewhere. What kind of drain plugs are on the driver side of the engine that I could check? Any replies would be greatly appreciated.

 

Start by washing the engine. I prefer Gunk Engine Brite (not foamy), but things like Simple Green/Purple Power/etc. are effective. Be prepared to remove the distributor cap & dry it thoroughly before cranking the engine. If you use Gunk, follow the instructions on the can.

Study this diagram:

 

Did you check the lifter covers (2)? They come loose just like the valve cover over time. Actually it's more likely the gaskets shrinking. Wouldn't be surprised if their finger tight.

 

Valve cover or the oil pressure switch near the rear of the block. My son's 4.9L had a leak in both places before he traded it a few years ago.

The fix:
1. Replace valve cover gasket, neoprene/rubber if possible.
2. Replace the oil press switch, use teflon tape on the threads.