I am looking for a pole on the best o-ring material... I know I need to change them after time from the ULSD, but with what? I have nitrile ones from my harbor freight o-ring kit. But what will last?

Viton?

Nitrile?

Any other type that will hold up well which I don't know about?

Thanks!
Nick

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-E300d '99 350k
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-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

What is going to affect them is the change in the aromatics (perfumes) used in LSD vs ULSD as that, rather than the fuel istelf, is what affects rubber components.

If you don't use Bio you should be fine with the OEM Buna (nitrile) orings, otherwise viton would probably be a better choice.

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Terry Allison
N. Calif. & Boca Chica, Panama

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

What makes you think you need to change them to anything other than the stock material?

I guess I just figured the stock o-rings leaked, maybe a different material wouldn't shrink.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

ULSD will eventually eat Buna-n o-rings. Replace them with Viton o-rings.

__________________
Never a dull moment at Berry Hill Farm.

I wouldn't worry about it, if they leak it's time to replace them regardless of fuel. I haven't heard anyone credible recommend changing the material. There are better things to worry about than this ULSD nonsense.

MB has not seen fit to go to viton and still uses Buna. They also don't recommend Bio products either to my knowledge, the exception being a very low B5 or B15 approved commercail blend on the new CDI's.

My personal feeling is that bio in higher ratios will effect buna orings.

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

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

In the 1990s, the government of New Zealand has conducted a study that determined ULSD shrinks the seals in diesel IPs and recommended changes to Viton seals. Is that credible enough?

__________________
Never a dull moment at Berry Hill Farm.

Not coming from you apparently

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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
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#1995 E320 Touring
#1985 300D Sedan
OBK #42

Viton. For every fuel you can run in a diesel.

__________________
'83 240D with 617.952 and 2.88
'01 VW Beetle TDI
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http://i16.photobucket.com/albums/b1...oD/bioclip.jpg

Can't you just cut some yourself out of an old cardboard box or something?

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I didn't know the government of New Zealand built diesel engines, maybe we should check in with Liechtenstein and see what they think?

I work with folks who use pretty large (3000 - 5000 HP) commercial diesel generators in critical applications. To date, I have not seen any diesel manufacturers recommending seal material changes for ULSD. Everything I have seen indicates that some seals may leak a little sooner and should be paid attention to under normal PM. Trust me, if it was necessary to upgrade seal material, these folks would be doing it.

Regarding automotive IPs, I replaced my 617 IP about 50-75K miles ago and have been running ULSD without any issues. All seals will eventually leak, then they need to be replaced. I certainly haven't seen anything from DB recommending a material change, did I miss that memo?

As you can tell by the number of posts I've contributed to (Yes, I'm joking) I'm an expert. Therefor the following info may set off your B.S. detector. ULSD itself does not cause damage to BUNA/nitrile O-rings. According to a Cummins engineer, when ULSD was first produced in this country a solvent was used to remove the sulphur from the fuel. Well.... all of the sulphur was not removed from the diesel fuel and the remaining solvent attacked the sulphur in some O-rings. Hence the problems that some saw when they started using ULSD. WVO will cause your nitrile O-rings to soften. I've learned this first hand. I'm currently replacing the seals on the VE IP on my rabbit diesel.