Thread: 300 tdi filters

Originally Posted by isuzurover

Filters are not sieves (as I have posted many times on here). So changing a filter too frequently means that the your air/oil/fuel in your engine will be dirtier!

curious,how does changing a filter more often lead to dirtier fluids, I change the three filters and the oil in my 300 tdi every 5thou kms and I doubt one would find an internally cleaner diesel engine

Originally Posted by isuzurover

Simple. New filters have a fairly low capture efficiency. This increases exponentially as the filter loads, yet the pressure drop (flow resistance) increases linearly. So - for example, a new filter might capture 50% of 25 micron particles when installed, however this would increase to 90+% as the filter loads with particles.

The reason your engine is so clean is because of the bolded bit - you are changing the oil with the filters. I assume also that by "clean" you are talking about soot. Which the filters on a 300Tdi won't remove at all. Changing the oil is the only way you can remove soot from the oil of a 300Tdi.

Btw - this is the same principle why many people think engine "flushes" are so miraculous - dilution.

makes sense