Oil leak when jump starting??

[Growlerbearnz]

Yup, that's the vacuum pump alright- since a diesel has no manifold vacuum, they need a mechanical pump to make vacuum to operate the brake booster and the EGR valve.

On our vacuum pumps the oil from the turbo flows through the vacuum pump- the oil seals the pump better, and the vacuum action sucks the oil from the turbo, preventing pressure buildup. It's a win/win situation. The big rubber pipe that goes into the sump returns the scavenged oil to the sump.

It sounds like the shaft seal on the pump has failed, allowing oil into the alternator (and then out the failsafe hole).

You're going to have to pull your alternator, remove the vacuum pump, and replace that seal. I'd check out the alternator's guts too, as that much oil can't be good for it.

Not sure why it's doing it most during a hard start. Lots of oil going into the turbo, but the vacuum pump not spinning fast enough to prime?

[jaggedfish]

Just to add my 2-cents to the fray and provide a different perspective...

Are you 100% sure this is where the leak is? Looking at your pics, it appears there is a more significant leak above the oil filter (bottom right of pic 40). It is conceivable that the oil is running down the engine and only dripping from your suspect location, giving the appearance of the leak being in that location. A lot of the areas in the pic appear wet with oil so it could be getting sprayed with oil under pressure. I know you just changed the filter but that seems more messy than just a filter change. Just playing devil's advocate on this as I have seen leaks occur in more usual locations that give the appearance of being in an unusual location.

Actually now, I think I am oriented upside down... the wet drip at the bottom of the pic IS from the filter change - looked closer at the drip direction. There are still other wet areas under there though. Just trying to help...

[NoDelie]

I may be off topic or it might help. I had a 1984 vw rabbit diesel and had 15w40 oil in it at a time when it was cold out like -10. i started it and it took a time or two to get it going but it started. Then the oil leak happened. It was the head gasket. I will explain.

This is what i learned. A diesel works on pressure and is considerably higher than gas, so with thick oil and cold weather the pressure is higher. Under this pressure it needs to find a way out so the head gasket is the weak point. and that is how most diesels die.Now if you have a oil pressure release valve on the block or the oil filter the oil will go there and save the head gasket. This is what you might be seeing coming from your cold start. I have found out that the vw 1984 did not have an oil release valve thus the head gasket went. Further more my oil filter did not have a by pass valve. Thus the pressure was all on the head.

If it is a cold start with a thick oil it has a very high pressure and it needs to vent. This is probable where it is venting. I now look and insist on a oil filter with a by pass valve and run a lighter oil in the colder weather. I currently use synthetic oil. I would not plug or be concerned about the globes of oil on a cold jump start. But i would be concerned about a continuous oil leak on a normal start in warm weather.I hope you have not blow-en any seals or gaskets on the head or oil filter seals and such . Have a look around.

[Delikatoon]

Many thanks to all for commenting on this. I perhaps should have started a new post. My oil leak problem was a related issue to the post "Oil leak when jump starting" but a vastly different problem. Sorry for any confusion.

Growlerbearnz hit it bang on based on what I have seen. Looks like I will have to pull the alternator to get at that seal. Several people noted that it was oily under the filter, possibly indicative of another leak, but that mess was caused by me when changing the oil and not properly keeping the oil filter vertically when I lowered it. The only leak is from that pinhole on the alternator.

thanks again