Quote:
Originally Posted by Tatsfield
My reference to 33% dilution was based upon the oil fill being reduced to 75% allowing 25% room for fuel dumping. 25% is a third of 75%. I'm not saying that my car actually has that degree of oil contamination, merely asking whether Volvo have actually allowed this large margin of contamination before the oil level sensor issues any warning. If the software upgrades have reduced the degree of contamination, why leave such a large margin to cope with it? This is just me being curious about the way Volvo design and develop engine modifications as I found it hard to believe that they could have put an engine out with that degree of tolerance on what is an unwanted side effect of DPF regeneration. Discussion rather than complaint.
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The range between the maximum and minimum marks on the dipstick doesn't represent the entire contents of your sump, just a relatively small range in which the level of oil in the engine is within the ideal operating tolerances. That upper 25% of the scale on your dipstick represents somewhat less than 5% of the total quantity of oil in the engine, so whilst any dilution with fuel is undesirable, it is nowhere near the level you are assuming.
I can't comment on whether or at what point Volvo consider the level of contamination to be excessive, but small quantities of fuel entering the sump during certain types of regeneration cycles is a feature of almost all modern diesel engines with emission control technology.
I also have a Ducato van. Dealers normally refill the oil to 0.4 litres below maximum to allow for a margin of dilution in use. On that vehicle, there is a software algorithm in the ECU which assumes a certain amount of contamination according to driving conditions, type of usage and the number and type of DPF regenerations. The counter alerts the driver if it considers that the oil needs to be changed prior to a scheduled service. Scheduled oil changes are at 24 months intervals on that vehicle. I change mine annually, but that's another story.