New Diesel Fuel Harmful to rubber gaskets?

[bear15]

Is the New Diesel Fuel Harmful to rubber gaskets? I spoke with a few Diesel mechanics who are reporting problems with the new Diesel Fuel in VW Diesel engines-- e.g. rubber gaskets & seals in fuel injector pumps degrade especially if the vehicle sits for longer periods of time. This repair is $500 - $600.


Any fuel additive suggestions?

[SVOboy]

They say it shouldn't be an issue for old cars: http://www.clean-diesel.org/vehicle_performance.html

I wonder...

[bear15]

Do you know of any suggestive additives?

Originally Posted by SVOboy

They say it shouldn't be an issue for old cars: http://www.clean-diesel.org/vehicle_performance.html

I wonder...

[omgwtfbyobbq]

I've actually heard the opposite. Diesel used to have additives that made the rubber swell, but the new usld doesn't, so after time those seals contract and the pump leaks. This seems consistent based an a couple bits of info I g00gl3d, but as with anything from the intern3tz, YMMV.

- increasing aromatics content increases swell in fuel system parts. Swelling of Viton and nitrile O-rings was within the appropriate ASTM standards on all commercial fuels tested except the 56 percent aromatics fuel containing 54 percent toluene;
- new and old rubber fuel system parts would not be expected to fail prematurely in fuels with total aromatic content of up to 50, or in 48 percent aromatic fuel containing up to 40 percent toluene, plus xylene;
- the amount of swell depends on the type of elastomer with Viton parts swelling significantly less than nitrile parts which in turn swell less than Neoprene parts;
- of the aromatic compounds tested, toluene causes more swell than xylene and mesitylene respectively;

From the NZ govt.

And from dodgeram dot org.

By definition, aromatic content is characterized by the presence of the benzene family in hydrocarbon compounds that occur naturally in the refining of diesel fuel. In the chemical make up of fuel, the heavier aromatic compounds of toluene, xylene, and naphthalene are also present. Limiting these aromatic compounds has the effect of reducing burning temperature and thus NOx formation.

Meaning that diesel fuel with a reduction in aromatic compounds in order to help out w/ emissions/NOx production, will also result in less swelling from seals exposed to blends that had higher levels of aromatics.

I've heard of painting the outside of the pump around the seal areas w/ xylene, or just replace the seals yourself if you can stand the work, but can't stand the price. There's also someone on ebay who's supposedly resealing pumps for much less than $500. GL!

[SVOboy]

Mehbe the old swelling that was holding the gaskets together is subsiding with the non-detrimental ULSD,

[trebuchet03]

Originally Posted by SVOboy

Mehbe the old swelling that was holding the gaskets together is subsiding with the non-detrimental ULSD,

I wouldn't think that the material would "unswell" -- but then again, I've seen some goofy things Somewhat newer stuff is made from neoprene, very new stuff might be something else... Non neoprene rubber hasn't been used for awhile

[omgwtfbyobbq]

Originally Posted by trebuchet03

I wouldn't think that the material would "unswell" -- but then again, I've seen some goofy things Somewhat newer stuff is made from neoprene, very new stuff might be something else... Non neoprene rubber hasn't been used for awhile

O rly? I have no clue myself since this stuff isn't anywhere close to my major, and even if it was, I probably still wouldn't know. But.......
Wouldn't rubber that swells from exposure to whatever blend of solvents, expand or contract according to the current blend of solvents? It doesn't seem like the solvents bond w/ the rubber, but instead that they fill it, kinda like a sponge... Course I'm a lay person, so I really do have no clue.

There's also posts like this and this.

How Will Diesel Change?

Diesel currently contains up to 3000 parts per million (ppm) of sulphur. The new lower sulphur diesel will contain at the most 600ppm and on average 500ppm of sulphur.

Reducing the sulphur content of diesel can result in changes to several fuel characteristics other than sulphur levels. Many of these characteristics, such as conductivity and lubricity, will be dealt with by the oil industry. This means there will be a smooth transition to the new diesel for most engines.

The desulphurisation process will probably also reduce the level of aromatic compounds in diesel. This reduction in aromatic content could affect some seals.

How Will the Change Affect Seals?

Seals in contact with diesel of high aromatic content often absorb the aromatic compounds, which makes the seals swell. If diesel with a lower aromatic content is then used, the seals may shrink back. The combination of seal shrinking and pre-existing ageing effects such as compression set or twisting can lead to seal failure and leaks.

[trebuchet03]

^^ that's why I wouldn't think it would... For gaskets/seals, a neoprene blend is used to avoid just that... Ideally, you don't want any effusion - but even worse is to revert back. The biggest problem (at least a few years ago - things have likely) with neoprene blends was the elastomer nitrile - which, alone, swells up terribly in oxygenated compounds (like acetone et. al.). From what I have been told, mfrs have been changing their synthetic rubbers to take care of that (the "might be something else"). So for newer designs (as mentioned in the OP), it shouldn't be a problem.... But shouldn't is a pretty big assumption

I really wish I had the resources to keep up to date on this type of thing (rather than a few years behind)... On of my material's professors liked this one statistic: "80% of the steels the auto industry used 5 years ago are now considered obsolete." I don't know if that's true or not - but materials are changing very frequently

[Lug_Nut]

I was warned that switching my used (500 ppm petrodiesel) TDI to B100 biodiesel would cause problems because the seals would, depending on who posted, shrink (or swell) and would create (or stop) leaks. Sorry to report that this hasn't happend to me.
Archival reports were that the switch from 5000 ppm sulfur diesel to 500 ppm diesel had the same warnings back about 20 years ago as with the more recent reduction from 500 to 50 ppm, "The sulfur is a lubricant. It's needed for pump life." Sulfur is also a friction material used in cutting fluids and match heads so who do you believe?
The removal of sulfur, the main difference in the now current 50 ppm fuel from two years ago when 500 was the fuel, may have prompted the addition of other compounds to compensate for any perceived loss of sulfur properties. These addititives, if any, may have an effect on the synthetic "rubber" compounds in the diesel vehicle's fuel system.
B100 biodiesel has no sulfur and no additives. I have no leaks since 2001 except for the self induced ones (forgot to tighten the hose clamps).

[Bill in Houston]

Originally Posted by trebuchet03

One of my material's professors liked this one statistic: "80% of the steels the auto industry used 5 years ago are now considered obsolete."

That statistic is now considered obsolete.

Just kidding. ;-p

[bear15]

Thanks for all the helpful information. We have a 1982 VW Vanagon (camper) which has a 1.6 L Diesel engine that we just got out for the summer.

If anyone knows of an additive that could help this potential problem, please post it here.

Originally Posted by bear15

Is the New Diesel Fuel Harmful to rubber gaskets? I spoke with a few Diesel mechanics who are reporting problems with the new Diesel Fuel in VW Diesel engines-- e.g. rubber gaskets & seals in fuel injector pumps degrade especially if the vehicle sits for longer periods of time. This repair is $500 - $600.


Any fuel additive suggestions?

[Lug_Nut]

Diesel fuel, as with any mineral based liquid, should not be allowed to remain in contact with natural or Buna rubbers. The oils in the fluids will leach into the rubber and begin to break the molecular bonds. This means don't let the oil leak from the cam gasket get onto the cam belt, Don't let the fuel spill remain on the radiator hose. Correct the wheel bearing to prevent slinging grease on the tire.
The fuel components use synthetic rubber and are quite resistant (but not impervious forever) to the effects of fuels and oils, but the other rubbers components under the hood not expected to be exposed to fuel may not be.
Any rubber, natural or synthetic, will eventually lose elasticity and plasticizers. A 30 year old tire isn't expected to hold 30 psi. An injector pump seal holding 3000 psi might be expected to weep a bit sooner than that.

[trebuchet03]

Originally Posted by bear15

We have a 1982 ....

If anyone knows of an additive that could help this potential problem, please post it here.

This is pretty much what I was going to say

Any rubber, natural or synthetic, will eventually lose elasticity and plasticizers. A 30 year old tire isn't expected to hold 30 psi. An injector pump seal holding 3000 psi might be expected to weep a bit sooner than that.

Given the age - it'd be hard to pin "new diesel" as the cause of any future failure...

[Bill in Houston]

So, hold on, sorry for the diversion. An '82 Vanagon, with the 1.6 liter diesel - Isn't top speed on a level road something like 65 mph?

[bear15]

Yes, when going down a slight hill we might reach 70mph. You must know this vehicle. We don't drive it very much but it is amazing that a vehicle as heavy as this one (Vanagon Camper) averages in the low to mid 30's mpg.

FYI, I just heard back from a VW rep. that confirmed the below using carefully selected wording.


[quote=bear15;26597]Is the New Diesel Fuel Harmful to rubber gaskets? I spoke with a few Diesel mechanics who are reporting problems with the new Diesel Fuel in VW Diesel engines-- e.g. rubber gaskets & seals in fuel injector pumps degrade especially if the vehicle sits for longer periods of time.

Any fuel additive suggestions?

Originally Posted by Bill in Houston

So, hold on, sorry for the diversion. An '82 Vanagon, with the 1.6 liter diesel - Isn't top speed on a level road something like 65 mph?

[Bill in Houston]

Interesting. Actually, I was just guessing based on a diesel Rabbit of the same vintage that I drove once.

You know, we often talk about having an engine just the right size to maintain cruising speed, and no larger, and it seems that you are there... And the payoff is that you get killer-good mileage for a vehicle that size and shape.

Anyway, thanks for answering my OT question, and good luck with the new fuel. The refineries spent a ton of money getting ready to make it, so I hope it is really great for users and for reducing pollution.

[omgwtfbyobbq]

Try aromatics like toluene, xylene, etc... The thing is, if the seal swell subsided, and the seals were stuck/ripped, adding aromatics to get the to swell again won't do anything. Which is what I think Lug_nut and trebuchet03 were trying to get at. I suggest getting a seal set, a spare pump, and trying to replace them yourself. There's also the ebayer selling reseals for ~$150.

[Ryland]

a brand new VW injector pump seal costs about $15, and should take about two hours to replace if you've never done it befor, of course if you don't have the right tools to reset the timing it might never get back together.
if you want to replace all the rubber fuel lines on a VW with solvint resistent lines, I figured a while back that it would cost around $20, at about $5 per foot for the fuel line, as most of the fuel lines are steel with rubber connecting the tank, and the pump, and the filter, and the only rubber seal that I know of is the main shaft seal on the injector pump, at least on the older VW's, newer TDI's and so on are suposed to have compatible rubber.

[Sludgy]

I've had no problems with the Powerstroke engine....... that includes 1/2 tank of off road (.2% sulfur) diesel last fall when I was deep in the woods with no other alternatives...... and no problems with new 30 ppm sulfur diesel.

[bear15]

Good news. Thanks for the information.

Originally Posted by Sludgy

I've had no problems with the Powerstroke engine....... that includes 1/2 tank of off road (.2% sulfur) diesel last fall when I was deep in the woods with no other alternatives...... and no problems with new 30 ppm sulfur diesel.

[repete86]

The additive that I suggest is WVO.