In Pennsylvania, we are starting the switch to Ultra Low Sulfur Diesel (ULSD) fuel. None of the gas station diesel pumps are labeled yet, so you do not know if you are buying ULSD or the old Low Sulfur Diesel. Anyway, the ULSD will cause some fuel lines and seals (o-rings) in older vehicles like my 1995 E300 diesel to shrink and crack, causing leaks according to recent data. My first symptoms were the fuel line leaks, leaving a puddle on the ground, and harder starting due to air leaks through the cracked seals. According to my dealer, I am the first in our area to have this. (Lucky me!) The cost of a total seal replacement was $397. (A question for anybody: Did I get taken???) Also, are there further problems with the deterioration of other parts down the road??

 

First I've heard of this problem with the ultra-low sulfur diesel. Surely there must be another chemical additive or by-product that is causing this rubber deterioration. I can't imagine that removing or reducing the amount of sulfur from diesel fuel would have this nasty effect on your rubber hoses and seals.

I remember reading something on one of the biodiesel boards about a similar issue on older diesel cars running on biodiesel/petrodiesel mix. If memory serves it has something to do with the trace amounts of remaining methyl acohol used in the transesterification process of biodiesel production. Older cars without fluroelastomer feed and return hoses running B20 were having real problems, and cars running richer biodiesel mixes from B30 --> B100 were having serious trouble. Like hoses turning gummy and falling off onto the ground kind of trouble.

So I'd say that there is a chemical culprit in the ULSD somewhere, or maybe there is an amount of biodiesel mixed into the ULSD. The only solution would seem to be upgrading your hoses and seals before you end up with an even bigger problem.

 

You are correct. It is not from the lowered sulfur but from the different aromatics used in the new formulation. According to Chevron's website, only a small percentage of older diesels will be affected with leaking seals and there is no way to tell which ones. See their website for further info. As for the unlabeled pumps, the Low Sulfur Diesel (LSD) are the only ones labeled because LSD will damage the 2007 and newer diesel engines. LSD and Ultra Low Sulfur Diesel (ULSD) will both run in older engines. The ULSD has been produced for a month or so and will be phased in to completely replace LSD by 2010.

 

I bought 1990 350 sdl from philadelphia, i drove it all the way to toronto, and now im leaking diesel from the injectors, could this be from the fuel in PA? We only use low sulfur diesel in canada.

 

I might be having a similar problem. I have a 1998 E300 TD and about 5-6 weeks ago I had problems starting it. It would crank right up and then buck and hesitate. The mechanic told me I had air in my fuel lines which in retrospect might have been from leaking fuel seals with the new low sulfur fuel in Pennsylvania. Before I knew about the fuel change I took it to the Mercedes dealer and they told me I had injector leakdown when starting and wanted to test the injecors which would have cost me $500 just for the diagnostics. I declined and I wrote an inquiry on this forum. A diesel fuel injecter purge was suggested, which was a great idea. I'm not that handy so I put injecter cleaner in the tank and the problem is almost 100% gone after 1 tankfull of cleaner. I thought the injecters might have been getting deposits from the anti-gel additive I put in the fuel for the last 3 years. Then I read about the low sulfer fuel in PA over the last month and began to wonder about a connection. I am relatively new to diesels and it seems when a problem can be found, it often is related to fuel. Any input would be greatly appreciated. Thanks.
Jon

 

I have cracked and perished o rings too around my injectors on my c250d, mechanic is replacing them all today,hopefully wont be too expensive, i think a lot of UK diesel is now uls.

 

Well i have my 1996 c250d back at home [euro model 5 cyl 2 litre 20v non turbo] turns out the o rings on the injectors were shot and the one on the lift pump wich is under the injector pump,apparently he had difficulty getting the seals as mercedes only wont to supply the complete pump with seals, this pump is immobiliser linked and needs reprograming by mercedes, pump cost was £300 and a reprogram £100, good job my independent mechanic is a diesel specialist who traced some seals and got them in there, you have been warned. Total cost for replacing all seals was £155.

 

Hi

Dose this effect the 80's Diesel modles.

Thx