Hey guys...got a question what should we use in our mercs to overcome ULSD and messing up seals or orings like I have heard it does...what additive? I have seen and used diesel fuel catalyst...but not sure..

I use the diesel fuel catylist, but for other reasons.

The reason it affects older o-rings is a combination of the lack of elasticity of the old rubber, and the reduced seal-swell from the lower aeromatic content of ULSD.

It seems in theory that adding a solvent to the diesel fuel that will increase the seal swell would prevent the problem, such additives are often used in the production of biofuels and WVO products and I'm guessing that seal leakage is less common for those running bio and WVO for that reason.

__________________

Gone to the dark side

- Jeff

I use Marvel Mystery Oil with some Power Service Kleen Diesel, and my car seems to really like it. Both have lubricating qualities and PS boosts cetane, so it seems as though all my bases are covered.

__________________
1975 240D (Euro 4spd man, Gold, 126,000km)

Lubrication of ULSD is in theory the same as LSD, and the Cetane is not a problem either. The bigger difference is BTU or the energy in the fuel, Cetane is an anti-knock type number like Octane and does help it to run more quietly.

__________________

Gone to the dark side

- Jeff

I have some Lucas fuel additive that I use ... often I buy grocery store 10-30 motor oil @$1.25/qt or less and add 5 oz per 10 gals or so of fuel.

I read many post of folks who don't believe extra lubricity is necessary, but I have strong memories of my parents trying to get home to NC from my sister's in Phila when the Feds did the first big change to diesel fuel, and having the engine run a couple of hours before the IP locked up. There were tractor-trailers all over the place, too. They finished the trip on the cab of a flatbed tow-truvk, with the car on the back. They started adding ATF with every tank & had no more troubles ..... and the IP survived and is still running, as far as I know, with no signs of distress. So I add a lubricity additive.

Many of the Dodge Ram Cummins turbodiesel forums that I visit recommend 2-stroke oil.

__________________
2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
-------------------------------------
'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

Replace the seals as they leak, nothing you can do about it. Age plus a new additive package is causing a bunch of fuel leaks.

__________________
2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

People are probably spending more money on snake oil than it will cost to replace seals if/when they eventually fail.

How about one of the simplest additives? Plain old Vegetable oil! I just get a couple of gallons and dump one in If I have to fill up with Fossil fuels, other than that, I use biodiesel!

I also have a '02 Ford Powerstroke & I have found that the use of 2-cycly oil mixed 1 oz. to the gallon works wonders for my engine. It quieted it down considerably, runs better & I even picked up a mile or two a gallon mpg-wise.

Keep in mind that the additives such as PS Diesel Kleen, etc., are full of things like acetone & other solvents. Might be OK for an occasional treatment, but nothing you'll want to run in your engine forever.

See: http://www.thedieselgarage.com/forums/showthread.php?t=57914&highlight=2+stroke+oil

How true Craig. I bought my Rod Bender ('94 S350D) in June '07. Come December my IP delivery valves are leaking like a sieve, so I order viton seals from Jim@fryerpower. Then I get to looking and the clear lines aren't in good shape, so I order them. After all that gets taken care of, I see the lines to the fuel heater are all cracked and seeping also. (I'm getting bubbles in the line from the lift pump to the main filter, so hopefully that why they're there). And since I had the intake off, a couple of the injector return lines are seeping now. The moral of the story? It's a 14 year old car and so are the lines, seals, etc. If they start leaking again then it's probably the USLD, but my bet is they're just old. I run waste turbine fuel supplemented with USLD when I have to buy Diesel and I throw Marvel Mystery oil, Power Services supplement and a quart of motor oil once in while.
Wayne

Common misconception. Sieves don't leak, they're supposed to do that.

__________________

Gone to the dark side

- Jeff

Ok bad analogy. They were leaking like, like, liiiiike a cow peeeeeeein' on a flaaaaaaaaaaat rock!!!!

OK.....but was the flat rock sitting in the hot sun???

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Absolutely nothing. ULSD comes with additives from the start. No need to add any more. IF your seals do start to leak they were likely to leak anyways. Spend the $25 on a 30spline socket and $3 on new seals. You'll spend much more on additives than the cost of properly repairing it.

We don't even know what vehicle you have. 85 and older engines (OM61x) use copper crush washers instead of o-rings. The chances of them leaking is very small no matter the fuel.