Community Forums

cvbdsl · 05-14-2016, 12:33 PM

Ok, I've asked this question on the Cummins engine forum when I thought this might be an exhaust leak but I'd thought I'd throw it out to a wider audience here.
On a long trip last fall with a lot of uphill/downhill driving I started to notice some oily deposit on the side of the valve cover. It continued to increase in size and after six or seven days covered the entire side of the valve cover.

I just got it back from a very reputable diesel shop and they said they have thoroughly checked the exhaust gasket and manifold and they are fine (though they did catch my lift pump leaking). A second mechanic checked it after I insisted and came to the same conclusion, it's not the exhaust.

If not the exhaust, what can be causing this? I'm thinking maybe some oil was coming out of the slobber tube and being thrown up? Slightly loose valve cover?

Any ideas?. Pictures below, in the second one I ran my finger down the cover just to determine the type of soot.

GGC · 05-14-2016, 04:00 PM

Probably not an issue. If you ever see some diesel engines being worked on, you would be eating off of yours. They will all leak at some time and with some miles on them.

dennis45 · 05-14-2016, 04:19 PM

I tend to agree with your mechanic. I suspect it is residue off the crankcase breather tube. There are ways to deal with that. One is to fab a catch can on the end of the tube. Just do not reduce the size of the tube in any way that would result in restriction. Bad,,,
I made one from a plastic bottle and plastic fittings because I was getting tiny spots of oil on the toad.
There are off the shelf choices also.

Oil Catch Can Breather | eBay

TQ60 · 05-14-2016, 09:40 PM

Get a spray bottle and mix a strong batch of dawn and water.

Warm up engine just a bit then spray area then rinse.

Maybe soak it and let it stand over night and rinse agsin.

Then check often for new oil.

cvbdsl · 05-15-2016, 09:48 AM

Thanks for the ideas.
Next weekend I should get time to crawl underneath and look at the slobber tube and see what I can do. I'll also clean of the existing residue to start fresh.

thanks

Chris