I just hit 20,000 miles and was under the engine changing the oil today.
I notice a film of oil, very slight, on the grounding bolt on the block, just to the left of the computers toward the front of the truck. There was a little oil on some brackets above that too. But... I couldn't find a source, at least not an obvious one. This is on the opposite side of the block from the filter, so that's not a suspect. Looking down that direction from the top, there's no obvious trail of oil coming from any gasket or vent I could see... It's above the pan gasket. I didn't have time to go poking around, it was not much oil (I get no drips on the garage floor), and I don't consume oil...

Still I'd like to figure out what's up. Any ideas? What are the "usual suspects"? Thanks.

 

Breather or P/S pump.

 

Breather would be OK?

P/S pump is a maybe... it was along the line of where I was looking.
That can't be good though... I don't even know how to check a level on that either.

 

Breather is pretty normal. Almost guaranteed after an oil change because you'll overfill. (There's a lot left upstairs while you're draining the downstairs.) Cummins will even things out in short order and you'll get a free undercoat at the same time.

P/S pump is no biggie in most cases. Merely forcing the front wheels into a turn with the nose on a lift and the motor off is enough to make it burp. It caused me some concern for awhile, but it's not something to get very upset over. By the way... Both my '94 and '99 did this. I haven't encountered it on the '04, but I suspect the same.

 

That's how I discovered my CP3 pump was leaking. It was diesel fuel not OIL. Take a flash light and look at the pump where it attaches to the aluminun mounting bracket, the seal on the pump fails and it will leak thru there and run down the bottom of the pump and drip off on the wires and brackets and side of block until it collects at the ground wire. Check this out. They are/did have a problem with the pumps leaking.

 

ugh, it was a thin film and could have been fuel

sorry for my ignorance - what is the CP3 pump?

 

High pressure injection pump=CP3

 

It's the Hi-pressure fuel pump that does it all. Open the hood and follow the line from the filter canister to the CP3 pump, or look at the fuel rail and follow the supply line from under it to the back of the CP3 pump. What fails is the input seal (you cannot see it) it will weep/leak fuel when it croaks, there is no performance difference when it is leaking. The tech that replaced mine informed me that they have seen them failing. The only catch is STAR is making sure they are leaking. They kept my truck overnight the first time... cleaned it and tried to look for leak. It didn't do it there of course. So I ran it a few hundred miles and returned with fuel leaking down the engine agian. That did it and they replaced pump.

 

I will surely keep an eye on that leak now.
I cleaned the surfaces to see if it would re-appear.

Is are there other fuel pump failure symptoms? Or does it leak then just stop working?

 

Just leaks and keeps on working.

 

I was worried that the main seal was leaking as I noticed oil collecting at the bottom of the bell housing, but it seemed to have originated at the breather, and with a light I couldn't see any inside the slot at the bottom of the bell housing. It also looks like the manual tranny seeps a bit of oil as there was a spray pattern at the end of the tranny.

It didn't seem like engine oil as it tasted different ...... (just kidding about tasting :^)

 

Forgot to add.... I have noticed oil on the disc brakes, which seems like gear oil that has seeped a bit from the end of the sahfts, front and rear. I do fill the diff to the bottom of the fill hole, so maybe this is a warning that 1/4in down is correct.

 

It could also be the oil return line from the breather in addition to the vent tube. oil/crankcas gas mixture is sent to the top of the valve cover where it runs into the "impactor" that is supposed to seperate the oil from the air/gas. The air/gas goes out the vent tube, the oil is returned to the block via a fitting located just above the engine control module (ecm).

All above posts are good things to check.