Engine Damage From
Low Sulphur Diesel Fuel


New low sulphur diesel tied
to throttle shaft and injector pump leaks.

by Stewart Clarke - Director of M.B.M.

Go To B100 Home Page For More Info On Lubrication, Reducing Smoke And Engine Wear


Premature fuel injection system failure due to low lubricity diesel fuels is not covered by warranty!!

Here's what you can do...


Trucking fleets around Australia are reporting a rash of fuel-related seal failures linked to the recent introduction of diesel fuel with a lower sulphur and aromatics content. The seals in question are fuel injection and throttle-shaft O-rings and gaskets made with a rubber compound. Some of these seals are reportedly failing after as little as 3 weeks exposure to the new low sulphur diesel fuel. Engines with rotary injector pumps use diesel for lubrication, as contrasted with in-line pumps which use crankcase oil. As a result, engines with rotary pumps are, at this time, the hardest hit.

The problems are apparently an unexpected result caused by the fuels mandate which has taken effect. On 1 January 2000, Western Australia became the first state in Australia to achieve “Euro II” (Low Sulphur) standards in diesel fuel and to eliminate lead from petrol.

BP Australia planed for W.A. to continue to lead the nation by moving to state-wide use of 500ppm (0.05%)Low Sulphur Diesel in 2001, and 50ppm Ultra Low Sulphur Diesel before National Legislation, which is due in 2005/6. BP on their web page has acknowledged the problem and the health effects of particulate matter!

The supply, purchase and use of Low Sulphur Diesel in Australia become mandatory for all locations in Australia since 1st January 2003. All diesel fuels for on-highway use must have a maximum sulphur content of .05%, the same as the maximum allowable in southern California since 1986. Before this, diesel fuel was allowed to have a sulphur level of 0.5%.

Apparently, one source of the trouble is that there are many ways to remove the sulphur content. The cheapest of these involves hydrotreating, a process that removes sulphur by treating it with hydrogen. Unfortunately, hydrogen is highly reactive and also reduces the lubricity, or lubrication properties, of the end-product diesel. Another factor in the equation is the initial content of sulphur in the base crude oil; crude from Alaska tends to be very high sulphur, Venezuelan relatively low, for example. As a result the lubrication properties of the fuel could be different for each oil refinery and can even change as a particular refinery's crude oil sources change.

The environmental benefits of the regulation are commendable, in that these include a significant reduction in particulate emissions. Reducing sulphur also decreases the acids formed in engine combustion chambers, which offers the promise of extended engine life. On the downside, however, the reduced lubricity may cause accelerated wear to fuel system components.

Cummins engines seem to be among those hardest hit by the failures. Bob Scholtz, the director of fuel systems and electronics service engineering for Cummins Engine Company (U.S.), said that he has received "reports of rapid, almost instantaneous occurrences of throttle-shaft O-ring leakage". Although the only leak point which Cummins confirms is their fuel pump throttle shaft, U.S. national trucking companies have reported leaks at other locations on Cummins equipment, as well as with other brands of engines. Blaine Johnson, director of maintenance for Ryder Truck Rental, said "This is not just a Cummins problem, it is a seal problem. We've verified seal failures on Navistar 743 engines, Cat 3208 engines, Mack transfer pumps...in all cases it involved a few Buna-N seals."

Contact with auxiliary engine manufacturers confirmed that all were well aware of the diesel fuel change and its potential for problems.

Dick Walker, Branch Manager with a Detroit Diesel, Perkins and Allison engine distributor (U.S.), says that "probably almost every engine model of most all makes and brands is going to experience some problems if they use rubber type seals in any of their seals. So far, it looks as though engines which have always used low sulphur fuel as their primary fuel are okay. High sulphur fuel swells the seal ring up, and then switching to low sulphur shrinks the seals and cracks them". So far he has not seen any failures of Perkins auxiliary engines which fit the profile of this condition.

On the Detroit Diesel side, however, he said that some problems have been seen but that it is too early to tell if they are related. There have been failures of body seals on the injectors, though, so there may prove to be a correlation.

The current official company position of Detroit Diesel is contained in a memo sent to the company's distributors by David M. Mayoras, Detroit Diesel's vice president for on-highway sales (U.S.). It said, in part, that "Detroit Diesel materials [which are] in contact with fuel are not susceptible to attack from low sulphur formulated fuel, as has been experienced by other heavy duty diesel manufacturers in their equipment. The material selection is such that it is better. When the competitors adopt the usage of better materials, they will have solved their problem."

John Deere (U.S.) also sent a bulletin to its engine distributors, in which the company cited the possibility of "fuel injection pump wear or internal failures caused by low sulphur fuels [on its] 300 and 400 series with rotary-type fuel injection pumps. Complaints or symptoms include premature rotary fuel injection pump wear or failures, engine speed instability, injector/injection nozzles plugging, hard starting, low power and engine smoke". It went on to say that "sulphur is an antioxidant, so fuel quality could also degrade faster during storage".

Deere recommended using a diesel fuel conditioner like B100 as a 2-5% additive, which is specifically for use with low sulphur fuels. In addition to providing lubrication properties, the company says the additive also contains a "Cetane improver". Deere claims that the product will prevent the symptoms listed previously, but that once they appear then only an injection pump overhaul will cure the problem. The company also has stated for the record that premature fuel injection system failure due to low lubricity diesel fuels is not covered by warranty by either John Deere or the manufacturer of their fuel injection pumps. Or any other company will warranty a product that they do not produce for that matter.

According to Ralph Metcalf, the National Service Manager for Isuzu (U.S.), he said that the Isuzu engines usually utilize the in-line Zexel pump, not a rotary pump. These do not have any rubber components in contact with the fuel. As far as I am aware, we have to date had no reports of unusual fuel leakage on any of these engines.


Here's what you can do:


If you operate diesel equipment, even if you have not switched from high sulphur to low sulphur fuel, we recommend that you take some steps to minimize the potential effects of this problem. The first step is to put B100 into your fuel. Second, instruct your drivers and maintenance personnel to watch for any pooling of fuel under both the chassis and auxiliary engines. If some is discovered, get it fixed immediately. Some reports have been made of fuel leaks so bad that they gushed diesel onto the ground; if allowed to get to this point it could necessitate an environmental cleanup cost.

Leakage can also occur into your oil, so also have maintenance monitor oil usage closely. If your oil level increases, or doesn't go down over time as usual, you may have an internal leak. Unfortunately, until the leakage amount becomes large enough to notice as an increase in dipstick level, a relatively expensive chemical analysis is the only way to determine that diesel is mixing with crankcase oil.

As far as we could find out, refineries aren't yet or going to putting in a lubricity additive. The cost is remarkably small, on the order of one cent per litre. Ask your fuel distributor if a lubricity additive such as B100 is being put into the diesel you are buying. If it isn't, encourage your distributor to start putting in B100.

You also might check to make sure your parts supplier has fuel injector and throttle O-rings in stock for your engines. Since the parts themselves are so inexpensive, you should consider keeping an extra set in stock yourself. If you have questions, call your engine manufacturer(s) directly to find out the latest on this situation, and find out if there are any precautions which pertain to your particular models.

Predictably, it will take months for the exact causes and effects to work themselves out. Taking advance precautions will ensure a minimum of downtime if your equipment does experience this type of failure.

Link to B100 site here!

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