Leak Diagnosis Help (pic inside)

[slow_90firebird]

Hey guys lately i noticed a few more oil drips in the driveway than normal. Crawl under there and it looks like the rear main is leaking. I pulled the inspection cover off and its bone dry inside the bellhousing!

I snugged up a bunch of stuff like tranny lines, valve covers, oil pan, tranny pan, etc. Sprayed 2 cans of degreaser all over everything and really cleaned it good.

This is what I found after 40 miles.


So do you guys think that looks like the diaphragm pump is starting to sweat a little diesel out? Or just the gasket from the pump to block? Oh I already tried snugging those bolts also.

[ellis93]

I'd say change the pump and gasket then forget it

[captmatthew1]

i have the same thing going on with mine. havent had time to get to it, but ordered one from geno's garage. thats the least expensive i found. maybe there is a better deal but i think i paid 50 bucks shipped. i even got a free cummins decal for the back window! lol

[slow_90firebird]

Is this a part that needs to be gotten from cummins? Or are the aftermarket replacements up to par?

At first I saw opportunity for the LP piston upgrade... But remembered I had a small diesel leak from the IP after I did the gov spring I never changed any seals and it was seeping from under the pump top. But the leak cured itself after a week.

I am afraid that even the LP piston might be too much pressure for this old girl to handle. Might be opening up a can of worms...

[ellis93]

I have one that's 2yrs old from oreillys on my truck,seems ok.

[cmann250]

When I replaced mine, I went to a Cummins/Bosch dealer (Scheid) and asked about the quality difference. The simple explanation I got was you are paying for the Cummins name. I'm running a Delphi lift pump and I have no issues. Mine was dripping out of that pressed on ring around the lift pump. I also looked into the low pressure piston lift pump and I should have just ponied up the money and got it. I'd go for it if there is any small thought in your mind of turning up the truck. I'll spring for the LPPLP next time

[slow_90firebird]

I have already turned up the truck. Alot. 366spring, full throttle travel, 7turns power screw, bottomed star wheel and rotated pin. 1/8" timing advance. Truck hazes at idle now with stock injectors.

I have no idea what the stock pump makes for pressure but it's gotta be close to nothing when I floor it. But it runs great no issues.

[91bluecummins]

ive always heard when the pumps start leaking it time to replace them . mine did the same thing and i replaced it with a 150 raptor