Well, it finally happened. I filled up my 2008 F350 with Low Sulfur Diesel before I realized what I was doing. Does anyone have any real experience with this? I ran through the tank with no immediate ill effects, and it was due for an oil change (20K), so the oil got changed shortly thereafter. I was pulling a light (<2500 lbs gross) trailer down the interstate.

If running the occasional tank of LSD is really a problem, what is the best thing to do next time (I ain't gonna drain it): just run though the tank (get the higher sulfur levels out as soon as possible) or add ULSD to dilute at, say, 1/4 or 1/2 a tank?

 

Well there's a big difference between 500 ppm & 15 ppm sulfur content between the two so I don't think diluting will help you much.

Repeated use of LSD will likely cause your DPF to fail prematurely. If the computer has a way to record improper fuel use, or there's any evidence of improper fuel in the system during a failure, Ford may not want to honor warranty issues.

Try posting the same question down a few lines in the 6.4 diesel forum and you'll probably get better answers.

Welcome to FTE.

 

I think F350-6 has you pretty much covered on what can happen. You will damage your DPF and other exhaust/emissions equipment. Ford also says something about it getting into the oil and damaging the engine, but I don't know if anyone here has figured out how or if that could actually happen.

I have to ask how you ended up getting LSD? As far as I know the only way to get it in the US anymore is off highway fuel that is dyed. If you ran that, you were taking other risks as well (staining of fuel system components can allow them to void warranty, if the law catches you it carries hefty fines).

 

We live in a different world down here. There is still LSD available at many stations & truck stops. Some even offer both LSD & ULSD.

If he lived a little closer to me I'd be more than happy to pump out and take all the LSD he wants to buy.

 

LSD is still the only fuel available at a couple of Pilot truck stops around here. But I usually get my fuel at Wilco/Hess, and they have had ULSD for about 8 months now.

 

Running LSD won't hurt your engine, except perhaps shorten this PARTICULAR oil change interval. The higher sulfur levels will build up acid in the oil as the tank burns, that the newer CJ-spec oils aren't really designed to deal with. It's POSSIBLE that the single tank will give your particulate filter (DPF) some problems a ways down the road, mileage wise.

Note that diesel with 16 PPM sulfur is still legally "LSD", while ULSD is 15 PPM sulfur.

I'd suggest making a call to the fuel retailer's manager and finding out just what the level of sulfur in their fuel is. Most LSD these days is between 20 and 100 PPM sulfur.

The reason the DPF's don't like LSD is not the fuel itself. It's actually the engine oil (burned) they don't like.

Fuel at the former 500 PPM standard would generate acid in the oil as the fuel burned. The oil had to have a certain chemistry to neutralize this acid to keep it from damaging bearings and other engine surfaces. The compounds in the oil that neutralize the acid, when burned, will clog the DPF. The oil chemistry had to be changed to keep the DPF from clogging, and that necessitated the change in sulfur levels in the fuel.

Of course, this is all dependent on your dealer, and how PSD-friendly he/she/it is. I can't imagine that Ford doesn't have a policy in place to deal with this situation. On further reflection, their policy is probably one of two things: either DILUTE DILUTE DILUTE, or drain the tank and re-fill with ULSD.

-blaine

 

Actually, running LSD in a 6.4 PSD WILL hurt your engine.

Cut from the 2008 Super Duty Diesel Supplement, 3rd printing:


Using low sulfur diesel fuel
(16–500 ppm) or high sulfur diesel fuel (greater than 500 ppm) in
a 6.4L diesel engine designed to use only Ultra Low Sulfur Diesel
fuel increases the likelihood of engine oil dilution with fuel which
may lead to major engine damage. Engine damage from using the
improper type of fuel is not covered under your warranty.

 

Interesting. I don't quite understand how that works, or how 16ppm fuel could be fatal, but I guess that means an oil change is in order immediately after getting ULSD back in the tank.

That would also mean the dilution method won't work if your starting out at 500 ppm and you MUST get at or below 15ppm.

 

I know...I would love to hear an explanation on how this oil dilution problem happens, it doesn't make a lot of sense to me. You have 1 PPM too much sulphur and your oil magically turns to 1 weight? WTF?

 

How do you explain sulfuric acid formation; reduction of TBN in oil forumulations; TBN of oil in the first place; and how they affect engine life; to someone who barely knows what the difference between gas and diesel is?

Remember that Ford is writing it's manual for the lowest common denominator here.

Only ONE tank *probably* won't do any damge. There are two considerations here; one is that the CJ-4 spec and earlier oils will clog a DPF fairly quickly, and Ford has to warranty that baby for 100K miles. The other is that long-term usage of 500PPM fuel may increase the acid content of the oil past it's ability to neutralize, and start inducing bearing damage.

Nnote the bold italics. It's the oil, not the fuel, that will give your DPF problems, and was the reason for the drop in fuel sulfur.

Dilution happens via combustion byproducts; specifically, water and sulfur. (water is a combustion product, and sulfur doesn't generally participate in the fuel burning equation.) During loaded operation, most of these are either blown out the tailpipe, or are boiled off and re-burned in the CCV system. During low temperature operation, or during extended idle periods, the engine oil does not get hot enough to keep this junk from being boiled off. The water and sulfur (and a little heat) cause the formation of sulfuric acid. This winds up in the crankcase, suspended in the oil. Since you can't separate it or dump it easily (except during an oil change) you have to have some way of neutralizing it. The oil has neutralizing properties, collectively referred to as "Total Base Number," or TBN. The compounds responsible for neutralizing the acids are ALSO the compounds that clog DPF's, in the form of ash. (And catalytic converters, thus the fairly substantial change in oil chemistry in cars back in 1996 when NOx catalysts started being used in cars.) How does oil effect a DPF, you ask? The oil gets burned (as in any other engine) during blowby (i.e. normal engine oil consumption). There's nothing new or strange going on in the engine.

The only way to keep from clogging the DPF's is to reduce the TBN of the oil. In order to keep your OCI from being reduced to HUNDREDS of miles (like 800-1500) instead of the normal 5000, the feds had to reduce the sulfur content of the fuel, since it was the reason why the DPF-clogging compounds were in the oil.

I was looking for a web picture of a Rotella "answers" column printed recently in trucking mags. I can't find one online, but it shows the difference in a DPF substrate when used with both CI-4+ oil and CJ oil. There IS a noticeable difference in the number of ash-plugged cells with the CI-4+ oil.

The FUEL concern with ULSD is the lubricity component, on high-pressure fuel system components. But nowhere does this concern effect the oil.

-blaine

 

OK Frankenbiker. I'll pretend I understood all of that. I guess the recommended course of action would be to run the tank almost empty, top off with ULSD, & change the oil.

Since the oil condition seems to be so critical, are there any components in the 6.4 that do not drain during the process of an oil change like the HPOP in the old motors?

So what relation does the condition of the oil, if any, have to do with the regen process? Could more frequent oil change intervals lower the amount of regens? If so I wonder where the break even point will be as far as fuel savings. Do you know of any magic numbers to look for if an oil analysis is done that will tell you when to change the oil?

I'm sure cleaning or changing the DPF won't be nearly as expensive by the time most people are ready for it. I'm just curious about any change in "normal" maintenance with all these new gadgets.

 

The condition of the oil has nothing to do with the regen process itself. The oil has been reformulated to remove most of what was the problem in the first place. The regen process takes care of the rest.

The regen process burns off 2 things: the soot from the unburned fuel, and the ash from the burned oil.

What they'll likely do is the same as the "big guys" are doing; that is, REPLACING the DPF when it comes time for service, as opposed to the dealer-performed "super-regen" process. That process take 4-6 hours on dealer-specific equipment. The trucking manufacturers have predicted that it will cost less to replace the DPF with another, cleaned, unit than it will to shut the truck down and enter it into the service queue to have it cleaned -- at some dealers, getting into the service bays can take 3-5 days.

Maintenance shouldn't be any different than another pre-2008 vehicle. The emissions controls are designed to not require ANY user intervention.

I remember hearing at one point that in normal operation, regen wouldn't occur but two or three times in 100K miles. It's not something that happens on a weekly or monthly basis, even though you see it being performed on a demonstration basis several times a week. Having a weekly regen event that required a specific driving pattern would hardly be considered to be "transparent."

-blaine

 

Thanks for everyone's input. Frankenbiker, that's what I was looking for. That tank was spent driving down the interstate, and the oil was changed shortly thereafter. The 20-100 PPM LSD spec you mentioned is interesting.

Beerstalker, I've actually run across LSD (or at least, pumps labelled as such) all over the place, from Chicago to North Carolina to Texas. Just my luck, I guess. There is a stretch of IH 10 just west of Houston (Katy-Brookshire) where there seems to be nothing but. As F350-6 said, some places have LSD (labels) on one side of the pump and ULSD on the other side.

 

Thanks for the insight so far you've been helpful, but I think you might be confusing DPF longevity on the big trucks compared to the souped up, my engines better than your engine, light truck market. I thought I read the DPF in the superdutys was supposed to be good for about 120,000 miles. That would require several regens along the way before cleaning/replacement was warranted. I know there are differences in driving situations and that will affect DPF longevity, but I'm guessing even the bobtail market will get better life out of their DPF's without the added power a pick up seems to require.

 

Actually, the big truck market DPF's only have a "lifetime" of 100-150K miles.

There are 2 cleaning processes used on DPF's. The normal, fuel-burning regen cycle that happens when the ECM senses the DPF is becoming restricted, and the much more intensive cleaning when the fuel-burning regen no longer cleans out the DPF. This happens on EVERY DPF, no matter what truck it's on.

Since design lifetimes of "light duty" trucks are only 100K (or so) miles, and it takes generally anywhere from 4-10 years to accumulate those 100K miles, that's the entire design life of the truck.

A big truck, on the other hand, can have that many miles put on it in 6 months (if a team truck) or a year (if a solo truck), and they have the same 10-year design lifespan.

Once the DPF can no longer be acceptably cleaned by fuel burn, it must be removed from the vehicle and cleaned on dealer equipment. As I recall, this is much more prolonged heating, and and a blowing out. The figures I remember hearing were that it took anywhere from 4-10 hours to complete this process, and it wasn't something that could be done on the vehicle. yes, this was a MAJOR sticking point for getting them accepted on big trucks.

The proposed solution, so far, has been to replace the DPF with another, during a scheduled maintenance, instead of trying to perform the "super-regen" with the DPF still on the vehicle. In practice, no 2007-spec vehicles have been in the field long enough for this mileage limitation to come into play. It remains to be seen if this practice actually sticks in the real world.

In actuality, I suspect that many big truck fleets will switch over to urea-based SCR, since the technology (that I recall) does not require DPF's or their cleaning processes. It's an ideal application for mid-sized and local P&D fleets that come back to the same base every night, since they have scheduled maintenance performed by the local shop or on a specified schedule by a dealer. On the other hand, DPF technology is more suited to long-haul rigs that don't have a "home base" and don't keep regularly scheduled (time-based) maintenance schedules.

-blaine