Do Diesel Cars Need Fuel Additives?

I own a VW diesel car. I never use to put in fuel additives for lubricity or to increase the cetane level (similar to gas octane level). Most European diesel has a rating of 50+, most US diesel is anywhere from 39-45.

Your VW car requires at least 45. Yet, there is no way you will know that number because cetane is posted at the pump. The average US cetane levels are 40-42.

The reason why you should find out what cetane level is needed for your engine is because an engine that needs 48, yet only gets 43, suffers in combustion and the fuel is not burned completely causing more residue and smoke. The engine will be sluggish. Since you know that most diesel you buy will not be higher than 45 and more likely to be lower, a fuel additive that increases cetane should be used. Using the proper levels will provide a clean and more complete burning of the fuel creating less black smoke. Your engine performance will be increased because you are using the minimum cetane. There is no harm for using more cetane than needed, only not using enough, does. A good additive can increase the cetane number by anywhere from 3 to 7, which is a big improvement. Using the proper cetane level also creates better MPG.

I suggest using Diesel Kleene by Power Service, which can boost the cetane level six numbers and also removes water and adds lubricants. It costs around $7-9 for a quart. Another good booster is FPPF 8+ cetane Improver. It is $17 but treats 250 gallons and works great. Redline cetane booster works fine also. They all cost about the same and add about the same cetane levels.

Yes, use a fuel additive.