Now the SDL's Leaking - PeachParts Mercedes-Benz Forum

Mr. G · #1 12-11-2006, 02:57 PM

Well it's been 3000+ miles since the fuel change to ULSD and my 1986 SDL has followed the lead of my Powerstroke and started leaking. It appears that more than one of the delivery valves is leaking. Very wet on the top and down the side of the pump and starting to show up on the top side of the belly pan. This morning was the second time in three days I have lost fuel prime while parked nose up on my driveway. BTW the Powerstroke is leaking at the O-rings for the drain valve of the fuel filter canister.

The special socket is ordered and I am waiting for Phil to call me back on whether or not I need expedited shipping to get the O-rings quickly on the west coast.

Neither vehicle started leaking imediately. Only after 2 months exposure to the fuel.

Does anyone have an opinion of whether there are other problem areas which will soon manifest themselves? The fuel lines are not original but not new either.

Thanks

Hit Man X · #2 12-11-2006, 04:01 PM

I've had no issues on ULSD...

F18 · #3 12-11-2006, 04:22 PM

Mr.G...I think once everyone gets all their old "O" rings in the fuel system changed out that should be the last of the fuel leak issues.
Like you on my 98 E300 TD I have some weeping at the top of the IP on two of the six delivery valves. I have changed all the other O rings everywhere else except those because at the time they were still OK.

I have not heard of any internal components on the Bosch Injection Pumps failing....yet! Before I pull the exhaust manifold on my model MB I just want to wait a little more to see if anything else starts acting up so I can do the remaining stuff all at once. Also keep an eye on the fuel return/jumpers hoses from the injectors....those have a tendency to leak as they get older without a fuel change aggrevating them.

Does anyone know if the "O" ring material has been changed/upgraded to be ULSD compatible or are we just getting "new-old-stock" when we order replacements from Mercedes or FastLane?

Hit Man X · #4 12-11-2006, 04:56 PM

I know Viton makes some beefier rings.

Our SDLs are 20-22 years old now, I would have expected the seals to leak REGARDLESS. Rubber does not last twenty years. Ten is about how far I'd push it.

I just ordered new DV seals for my SDL, I'll keep everyone posted if they're updated or new.

2.5Turbo · #5 12-11-2006, 08:31 PM

My 300D 2.5T hasn't leaked yet from the IP. The return lines leaked a while ago but that was before ULSD, and they were really old. I add a couple gallons of B99 to the tank every couple times I fill it. I don't run it to empty every time, so the small concentration of bio stays in there for a while. Don't know if it helps or not, but I am sure the lubricity supposedly lost along with the sulfur has been restored.

nhdoc · #6 12-11-2006, 10:09 PM

The problem, as I understand it is not that the o-ring material is incompatible with ULSD but that the aromatics in the LSD cause the rubber to swell slightly and when the ULSD is introduced the rubber shrinks thereby causing the leaks. Once the fuel has been switched to ULSD there should be no further problem using the new rings, assuming, of course that there isn't prolonged exposure to LSD again (which is unlikely since the fuel is supposed to be out of the system for the most part after 10/15/06).

The europeans have been running ULSD for some time and using these same materials so I think they are OK...but the problem we have here is the switchover caused this....the same thing happened many years ago when LSD was introduced, BTW.

Mr. G · #7 12-11-2006, 10:54 PM

Quote:

Originally Posted by nhdoc

The problem, as I understand it is not that the o-ring material is incompatible with ULSD but that the aromatics in the LSD cause the rubber to swell slightly and when the ULSD is introduced the rubber shrinks thereby causing the leaks. Once the fuel has been switched to ULSD there should be no further problem using the new rings, assuming, of course that there isn't prolonged exposure to LSD again (which is unlikely since the fuel is supposed to be out of the system for the most part after 10/15/06).

The europeans have been running ULSD for some time and using these same materials so I think they are OK...but the problem we have here is the switchover caused this....the same thing happened many years ago when LSD was introduced, BTW.

Good explanation, thank you

dan_the_welder · #8 12-12-2006, 07:06 PM

Saturday when I got up, my 86 300 sdl would not start, and with very recent glow plugs and relay I suspected fuel supply. All the hoses were loose feeling and some just came apart. Changed all the rubber fuel lines and bled the system and she started up.

Since it was cold the day I did it I had to tighten all the hose clamps again on a warm day once I noticed it was leaking again.

Since then it was fine, but I did just notice we only got the new diesel here a tank or so ago. The hoses needed replacing but the info about the new diesel is interesting.