Thin film of oil in engine compartment

[Specop_007]

Reposting this as I stuck it in the 94-98 section. This is on an 01 truck.

So not sure if this is a problem or not to be honest. I have a very thin film of oil on everything in the engine compartment. Its actually so thin as to be almost dry but if you run your finger along the air filter cover, the radiator fan cover, anywhere, you finger comes back with just a bit of oily grime on it.

Is this normal? What could cause a very slight film of oil on the engine? I drove the truck home and let it set for 10 or 15 minutes, checked the oil and it was what appeared to be 1/2 quart over the full line on the dip stick.

Anything to be worried about?

[scraph]

The PCV (positive crankcase ventilation) system sends positive pressure in the crankcase (you'll get positive pressure in there due to heat up, blow-by, etc) back through the engine intake. These crankcase fumes contain some oil vapor. The flexible boots that connect the turbocharger to the intake manifold and the intercooler tend to allow this oil to collect and seep through the material. The boots get filthy with oil on the outside and, in the end, can result in a thin oil film all over the engine. Also, diesel itself is an oil and there are a few opportunities for diesel oil to slowly accumulate on the engine. You also have general road grime which can collect.

I wouldn't be concerned until you start to see puddles of oil forming beneath the truck. They will probably be draining down from the engine valley (the area on top of the engine block between the V of the cylinder heads). Shine a flashlight in the valley and dry up anything that may be in there. Check the valley again after a little while to see if you have anything new in there. That will tell you if you have any number of common oil leaks for this engine.