Tales of non-MB FI ruined by ULSD - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 02-12-2007, 09:47 PM

I subscribe to a mailing list, burnveggies@goblin.punk.net, that revolves around biofuels and diesel-engined cars, primarily in the San Francisco Bay area. Lately there have been numerous reports of VW TDI and BMW 524 TD fuel injection systems being "eaten" by the new ULSD fuel. The complaints have something to do with the rubber seals in the FI system.

I know little of Mercedes fuel injection systems and nothing of anyone else's. A 'short course' in comparative fuel injection systems would be appreciated from one of the many experts here. Why does Mercedes apparently not suffer from this same problem?

TMAllison · #2 02-12-2007, 10:43 PM

It does, it has.

The problem is the difference in the aromatics put into the new fuel which effects rubber componets.

It not that it is bad, but that it is different and causes o-rings (in the case of my OM606) to shrink resluting in fuel, or worse, air leaks.

I don't know of anyone who can attribute a pump failure to ULSD.

#3 02-12-2007, 10:45 PM

I don't feel that some rubber seals leaking should be called "ruined". I would call a pump ruined when it stops pumping fuel, barrel bores are scored, or physically broken.

mobetta · #4 02-12-2007, 10:51 PM

there were plenty of posts about leaking delivery valve seals over here for a while to, mostly the om 60x engines, i believe.

I do not recall reading about a 617/616 developing leaks due to ULSD.

and the ? is wether or not the fuel caused it, or if they were going anyways.

networkboy · #5 02-13-2007, 01:39 AM

Quote:

Originally Posted by ForcedInduction

I don't feel that some rubber seals leaking should be called "ruined". I would call a pump ruined when it stops pumping fuel, barrel bores are scored, or physically broken.

True enough, but it sure as heck qualifies as damaged and/or non optimal performance.

If you are pre '85 I highly recommend redline diesel fuel catalyst at about a 2:1 over their suggested mix rate. (I blend RL-2 and catalyst as a mix and use that as an additive package). I've had no seal issues and I'll put money that the nailing I was getting when I acquired the car was helped along by the additives (specifically RL-2). The catalyst is specifically formulated to help with lost aromatics, and is not ULSD certified (my local store has to put stickers on every bottle, even though they know I'm buying the entire case).

Speaking of which: CarQuest in Orangevale (greenback and walnut) CA will order all the RL additives you want without making you buy more than one bottle, if anyone in Sac has trouble finding it. I've been working on them to carry Lubro Molly products, but no luck yet.
-nB

#6 02-13-2007, 01:41 AM

I've been running ULSD without commercial additives (Only an ounce of acetone) since it was first offered and it has yet to leak a single drop of fuel.

POS · #7 02-13-2007, 08:34 AM

I've been running ULSD since summer of last year, and my 606 engine leaked through most of its lines last Dec. I've replaced them all and the leaked stopped. I mention this because just about that time I noticed A LOT of people having the same issue on these forums and through my own MB mechanic. Was ULSD the cause? Don't know.

dmorrison · #8 02-13-2007, 02:13 PM

This is the second time the sulfur content has been changed in diesel. Back in around 97 or so the EPA made the first change. Back then there were reports of 18 wheelers having had to get their injection pumps rebuilt. But the Bosch in line injection pumps did not have any problems. The rubber hoses did start to leak. I had to replace all the return lines as well as the fuel tank lines. It could have been due to age. I have not had to replace anything as of yet this time.
It does concern me about the ULSD's lubrication effect. The sulfur does provide a certain amount of lubrication and now that the supfer had been reduced will it effect pumps parts that used the diesel fuel for lubrication? The pump is internally lubricated by oil. But some parts depend on the diesel fuel. I guess we'll see.

Dave

mobetta · #9 02-13-2007, 02:18 PM

If your on the cheeeep, just add a pint of new veg oil or motor oil to the tank on fill up. it will add lubrication.

justinperkins · #10 02-13-2007, 03:04 PM

My TDI recently developed a leak at the IP due to a failed o-ring that seals the pump head (cast iron) to the pump body (aluminum). It's a common leak point and an easy afternoon fix, hardly constitutes the IP being eaten. At the time I developed the leak it was after I ran through almost a full tank of ULSD, it was the first non-biodiesel tank I had used in quite a while.

Parrot of Doom · #11 02-13-2007, 03:11 PM

I keep telling people, we've had ULSD in the UK for years now, and I've never heard of anything similar happening over here.

TMAllison · #12 02-13-2007, 03:24 PM

Quote:

Originally Posted by Parrot of Doom

I keep telling people, we've had ULSD in the UK for years now, and I've never heard of anything similar happening over here.

The reason is the aromatics in the fuel have remained constant during that time. The issue will slowly resolve itself here just as it did when LSD was introduced previously.

There were lots of 606 leak issues on the forum in late Dec and early Jan a few months after the rollout occured. Cold weather also arrived which prob excerbated the shrinking/drying out issues as well.

rrgrassi · #13 02-13-2007, 03:51 PM

I have not had any issues w/ ULSD in my car, yet...

Kynetx · #14 02-13-2007, 07:16 PM

I wonder if the VW TDIs that are having trouble are the Pumpë-Dusë* models. Kind of a dumb setup if you ask me.**

*To make the ë, hold down alt and type 137 on your numeric keypad
**Nobody has.

tenknots · #15 02-13-2007, 09:25 PM

It is not the lack of sulfur that is the problem - sulfur doesn't do anything except pollute. When sulfur is removed, the process removes lubricity as well. But diesel fuel is made to an ASTM standard which includes a lubricity requirement. To meet the standard, refiners simply add lubricity enhancers back in.

When diesel was changed to LSD a few years back, it was a huge change compared to the change we're seeing from LSD to ULSD. ULSD can cause seals to shrink (just as E10 does) but I suspect most cases of leaking are due to systems that were marginal anyway.

One thing I've learned about fuels over the years is that they are like the weather - there's nothing you can do about them. ULSD is here to stay. The vast majority of diesel engines will not be effected. If you are worried that the refineries are not adding lubricity, add 2% biodiesel or straight veg oil.