Engine/Transmission (1998.5 - 2002) ULSD and Lift Pumps

[RustyJC]

Has anyone else seen THIS bulletin from Cummins? :{



Rusty

 

[kscheffler]

Unfortunately it makes perfect sense

No, but if we have nitrile seals they will shrink with the new fuel. THis has been a common problem with nitrile seals in mine line of work, industrial wastewater. I wonder were else we have nitrile seals? You FASS and RASP guys better also take a look at the construction drawings of those pumps to determine seal materials. The preferred seal material is Viton or teflon...

 

[fkovalski]

Am I correct to assume that this will affect only the pumps that are located in the engine compartment and not the pumps that are located in the tank? (if it leaks in the tank, it just stays in the tank(?)... )

 

[kscheffler]

It will leak in the tank but it might also effect the discharge pressure of the pump.

 

[isb360]

This bulletin was issued by Cummins in August 2005 and the common 3990105 p/n is mentioned at that point as a recommended replacement. I would have to think that for it to be recommended, a different seal material (Viton, etc) was used with the p/n revision at least since Aug 2005, if not earlier. I have a 3990105 pump on my truck now, but can't remember when I purchased it. Time will tell if it leaks with ULSD.



I wonder if there are similar bulletins addressing other nitrile seals as part of the engine or fuel system.

 

[RustyJC]

Yes, it was issued in 2005, but the VP44-equipped engines it covers haven't been used in the Dodge Ram since the 2002 model year. It's sort of a big deal to me because I'm still running my original lift pump (16+ PSIG at idle), I took delivery on the truck on 8/15/01, I'm about to leave on a lengthy trip with the RV, I suspect that I'll encounter ULSD during the trip and I have no idea what gasket material was in use when my lift pump was built.



Rusty

 

[fkovalski]

I would assume that leaks on LP's that are visible would be covered under 5/100K (per bulliten recomendations)..... I am concerned that in the case in in- tank pumps, the condition if present would not be visible, hence no evidence for warranty coverage

 

[Gary - K7GLD]

I wonder if the addition of additives like Power Service and/or 2 stroke oil will prevent seal problems with ULSD?

 

[remarc31]

Gary - K7GLD:

I looked at the picture (taken by you) of the LP with the bottom plate and gasket laying by pump. If a person would take the plate off and apply some type of sealant such as (silicone or teflon sealant) on both sides at the sealing area, do you think this could possibly be the answer to avoiding a leak as described in the thread?

 

[Regcabguy]

Switch pump?

I just relocated my pump via Vulcan setup,leaving original '99' pump in place for psi comparison. I've got a p/n 3990105,manu date 21-DEC-04 replacement pump stored behind the seat. My question is: will this pump leak also or should I just put the campaign pump on? If the 3990105 pump is not compatible with ULSD is Cummins going to exchange it for an upgraded one with proper seals? Always something!

 

[Gary - K7GLD]

Gary - K7GLD:

I looked at the picture (taken by you) of the LP with the bottom plate and gasket laying by pump. If a person would take the plate off and apply some type of sealant such as (silicone or teflon sealant) on both sides at the sealing area, do you think this could possibly be the answer to avoiding a leak as described in the thread?

The gasket you refer to includes the circular metal bottom plate for the pump rotor and vanes - dunno how any foreign sealant could be applied that could be relied upon to completely seal that area - or if any ULSD-proof assembly is available for these pumps as a separate item.



In my case, I religiously use a 50/50 mix of PS diesel additive and synthetic ashless 2-stroke oil to my fuel - hopefully that will be enough to offset the drier ULSD...

 

[Silver Bullet Ram]

I don't care what they say, sounds like this ulta low stuff is going to be bad for our trucks..... i wonder if i should dump my truck?



Gary

 

[DMcPherson]

"Once the nitrile gasket absorbs fuel, the gasket expands and seals. If the fuel type is changed from LSD to ULSD, the nitrile gasket will shrink and no longer seal, causing a fuel leak. "

looks like new upmps that have not seen fuel should be ok

 

[fkovalski]

I... . i wonder if i should dump my truck?



Gary

That is a bit extreme, but I hear what you're saying. I would really like to see some conclusive evidence that additives will help the condition. But, then the EPA would ban additives.

 

[Gary - K7GLD]

Trying to put - and keep - all this ULSD issue in perspective, I seriously doubt there will a great and sudden rash of all out failures, What I *do* expect, is a FEW such failures, and LOTS of lesser annoying smaller ones that require eventual attention, A relatively minor drip/leak at a pump or fitting/gasket that WILL need to be corrected - but nothing that's likely to leave you totally dead in the water.



Also, DC isn't alone in this potential issue - GM and Ford - and others - are as likely to be affected as WE are!

 

[fkovalski]

Gary- agreed that there may be few trucks where there are issues... . one nice thing about the LIFT pump up in the engine bay is the fact that any leakage will be seen.



I am wondeering about pumps in the tank (like mine) where it will not be seen. A few post back (or in the other ULSD post) it was mentioned that a leak IN TANK may have lower pressure/ volume due to it leaking back into the tank

 

[Gary - K7GLD]

Gary- agreed that there may be few trucks where there are issues... . one nice thing about the LIFT pump up in the engine bay is the fact that any leakage will be seen.

In my case, since the truck is usually parked inside the garage, on a spotless floor, ANY leaks will be immediately obvious! My stock LP is relocated down on the frame rail, with the pusher ahead of it - I also use a similar Carter 5 PSI pump to transfer fuel from the in-bed tank to the main tank on demand. I will have LOTS of potential gasket leaks if the ULSD, even with additives in the mix, causes problems.



My VP-44 was just swapped out with a II rebuilt, and presumably is immune to ULSD issues...

 

[Nyoest]

Yay, another 24 valve fuel issue