03 Chevy 2500 has an oil leak only when running and it drops down consistently from the starter bolt closest to the transmission. I bought a scope to try and see where it’s coming from. Can see the stream of oil running down the curve of the starter, but cannot for the life of me see where it’s coming from. Any advice is appreciated. Hoping someone has dealt with this before. I thought is was the crankcase sensor after watching a YouTube video of a truck the same year doing the same thing. Was not it.

 

Check the oil pressure sending unit located on top of the engine behind the intake manifold.

Here is a link to a youtube video showing how to replace it.

If bad, I suggest replacing it with one from GM Genuine, Standard Motor Products (non T series), NAPA Echlin, Delphi, or BWD (non P series).

Good Luck!

 

I already did that. It was actually the first thing I replaced.

 

OK on the oil pressure sending unit.

Have you checked the tightness of the valve cover bolts?

 

Hi h_ponygirl-

I have a 2004 Chevrolet Silverado 2500HD and i had the same issue. It's your valve cover gasket, it leaks from the back and runs down. I just did my oil pan gasket, oil cooler lines/gasket, oil pressure switch, oil level sensor and i still had the leak. I was going nuts trying to find it, finally i seen it when it was running it was seaping slowly. Replaced valve cover gaskets both sides and while i was there i put new plugs and wires as well.
Good luck with yours.