Bill’s Quality Auto Care of Simi Valley provides expert auto repair and care for your diesel vehicle.

Although diesel engines can last 200,000 or even 300,000 miles while providing excellent fuel economy, they must be properly maintained to optimize their efficiency and service life. Here we present two issues that are extremely relevant to today’s diesel engines. Please do not hesitate to call us for preventive maintenance and repair advice on your specific diesel vehicle.

Cylinder Wall Cavitation

Cavitation is the development of cavities in the cylinder walls or liners of your engine, which eventually allows coolant into the oil when the engine is off, and oil into the coolant when the engine is running. This can happen in as little as 500 hours of operation when using water alone as a coolant.

Diesel engines have much higher compression ratios than gasoline engines. Higher compression ratios produce substantially more violent explosions inside the engine, creating the unique engine noise that we associate with diesels. Those explosions produce extreme pressures, creating tiny air bubbles in the engine’s coolant, which can implode and create pits that grow with time in a diesel engine’s piston cylinder walls or liners. This is known as cavitation.  Replacement of major parts, or even of the entire engine, is often the only solution.

Prevention of this ever-increasing problem is simple and inexpensive, and consists of the regular application of a supplemental coolant additive, or SCA, to your diesel engine’s cooling system at the appropriate intervals. A supplemental coolant additive adds a protective layer to the cylinder wall. Cavitation then attacks the additive layer instead of the cylinder wall.

Most vehicles need a SCA additive at 15,000 miles and a complete coolant flush every 30,000 miles. Diesel engines also require prompt attention to any other problem with their cooling systems.

Cetane Ratings and Sulfur Content

Recent changes in the composition of diesel fuel mean that today’s diesel engine components are simply wearing out faster. This can cause expensive repairs and reduce the effective life of your vehicle.

One hallmark of a quality diesel fuel blend is a high “cetane number.” Engine designers like to see a cetane number of at least 50.  However, the cetane level of US-market diesel fuel can vary, and is almost always well below optimum levels. At Bill’s Quality Auto Care, we have the equipment to measure our customers’ diesel fuel cetane levels right here in the shop. Readings as low as 34 to 42 are not uncommon. Performance will be reduced, and fuel consumption increased, in vehicles that use such fuels.

Another problem is the amount of sulfur that is found in diesel fuel.  Although sulfur can be a serious pollutant, it is also a lubricant.  Refineries must now produce a type of diesel fuel called Ultra Low Sulfur Diesel Fuel, or ULSD. That’s good for our air, but bad for our engines. Less sulfur in diesel fuel means less lubrication, which in turn reduces engine life.

This is why all of us at Bill’s Quality Auto Care feel that it is important to use diesel fuel additives each time you fill up, and why we’ve taken the time to seek out and stock the best additives available. Using them will increase your diesel engine’s performance and fuel economy while reducing repairs.

What Does This Mean to Me?

Today’s diesel engines are vastly improved over the old “oil burners” of the past. They can offer excellent fuel economy and lower maintenance costs. However, diesels are not maintenance-free, and they have their own unique service needs. Regular attention to diesel engines will help to realize the long service life for which they are known.