Diesel Engine Alert — by Gerry L.


Do you drive a pickup or a motor home with a diesel engine? If so, here’s a heads up about the ultra low sulphur diesel (ULSD) that has come on the market in the last couple of years.

Most diesel pumps now only give you ULSD (often referred to as “clean diesel”), which means they’ve taken most of the sulphur out. Sulphur provided the lubricity that several engine parts (most notably the pressure pump and injectors) require. When the sulphur was removed chemical additives were put in to provide the same function. Unfortunately, at least up to now, this does not seem to be happening and nobody seems to know exactly why.

One theory is that some of these additives are settling out in tanks and/or pipelines. In other cases these additives are mixed in at the dealer level with some irregularity in consistency and quantity.

Bosch Ltd. makes injectors for a lot of different diesel engines, including several different-sized Cummins engines like the ones in our pickups and motor homes. In the last few years there’s been a considerable uptick in warranties and replacements. For owners whose warranties have expired, this can be a costly problem: injectors at a Dodge dealer are upwards of $800 CDN each and most engines have 6 or 8 injectors.

Cummins, along with other engine manufacturers, has taken a considerable amount of heat over this issue. Its original position was use #2 diesel only — no additives required. Now, after testing a number of fuel additive products available at the retail level, the company seems to be changing its mind.

Several different manufacturers make these fuel additives. Cummins — which markets its additive under the Valvoline label — warns owners not to use any additive that is alcohol- or acetone-based. It also recommends that no additives be used in the 07.5 or newer Cummins turbo diesels (that is, those engines produced halfway through 2007). If you’re driving anything older than that, you should consider using a fuel additive.

Unlike newer vehicles, the gaskets & o-rings in older engines are not always compatible with ULSD so there might be some problems there as well.

Do fuel additives make a difference?


I drive a 2007 5.9 L Dodge diesel pickup. I started using these products in the fall of 2008 and have seen 2 separate benefits: first, the engine runs smoother and with more power; second, because most of these additives have a certain amount of cetane, I’m getting more miles to the gallon.

At some point I expect to see the fuel manufacturers getting a handle on this problem but since they are reluctant to admit that there is one, they may never get around to telling us if they have fixed it. But the information will trickle down through the engine manufacturers and/or dealer networks.

My advice? Talk to reps from the engine manufacturer of your vehicle. Get their bulletins/advisories. And get knowledgeable about the unit you’re driving and how the new fuel might affect it.



A word of caution. Years ago I drove a diesel car in which I used a fuel additive to get more power. At 500,000 miles holes got punched into the piston heads. Was it the additive? Who knows.

A Note:   When ULSD was first introduced it wasn’t available everywhere and drivers sometimes had trouble finding it. Not all countries — or states — came on line at the same time. Mexico apparently didn’t have it nationwide until September 2008. California jumped on board at the start and required it statewide as of September 2006. Rural Alaska, by comparison, won’t have to meet the requirement until December 2010.


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