DennisT

I was doing search for info on leaking lift pumps, (1997 12V). There was a reference to a Dodge bulletin about the new Ultra Low Sulphur fuel causing lift pumps to leak. Is this true???

Where can I read this bulletin??

Are all current replacement pumps designed to overcome this?

Thanks,
Dennis

AggieJustin

If I remember all the tech terms correctly, it's the process of removing the sulfur that removes additional aromatics from the diesel. It's these missing aromatics that cause existing seals to begin slow leaks when switching over to ULSD. The seals in the pumps that were running LSD basically absorbed some fuel/aromatics which caused them to swell. When you switch to ULSD, the seals shrink which causes slow leaks. The leaks may disappear over time, or you may need to replace seals (or the whole pump) if the leak is too severe or if it doesn't stop.

I know all three of our JD tractors have developed slow leaks since switching over to ULSD. They don't drip, but you can see the film of fuel over the pump and the area around the pump. They did the exact same thing a number of years ago when LSD first came out. Hopefully we'll get lucky again and the leaks will seal back up after a little more run time (especially since they're not leaking anymore than they are).

I'll have to search to see if I can find the official Cummins bulletin.

EDIT: Easier to find than I thought. http://www.blueridgediesel.com/CUMMI...905%5B1%5D.pdf

DennisT

Thanks. I'll bet that exactly explains my problem. New pump going in today; am keeping the old one for emergency spare. I wish I could bill my repair job to the Federal Government.

Dennis

infidel

This bulletin is referring to the 24 valve electric lift pump.

DennisT

Hmmm. Well, I wondered about that. So I will now figure that bulletin does NOT have anything to do with my 12Valve. So my lift pump leak is unrelated, and a symptom of normal wear. (129K miles, and probably never has been replaced).

Dennis