''DPF problems (or lack thereof) are basically dependant on duty cycle. Plenty of Mazda 6 2.0D clock up huge mileages without running away on their own engine oil.''

Don't find other makes steadily and regularly filling the sumps with fuel though.

Plenty of reports from owners and company car drivers who do cover suitable mileages having to get oil changes between services due to the oil level constantly rising.

Its not just the case of the engine running on its own oil (or fuel if its filled the sump) its the premature wear associated with diluted oil.

Its one of several Diesel engines i would avoid like the plague.

If the maker, along with others, had taken the trouble to fit their cars with proper tell tale instrumentation to inform owners of the state of regen, then much of this could have been avoided.

Its hardly science likely to confuse an owner for a warning to flash up saying ''continue driving if possible, regen 10 minutes from completion'' or similar, instead all owners are in the dark as to what's going on.

A friend of mine with a Mazda 6 2.0 diesel had dpf problems within 600 (mostly motorway )miles of purchase - from new! - followed by numerous visits to the dealer, All OK now though.

The best diesel DPFs seem to be the closed coupled ones which usually achive passive regen.

Edited by Big John on 16/05/2012 at 23:43

I doubt that you'll need to remove it. The best trick is to ignore the advice about buzzing the hell out of the engine to try to burn soot off. The only way to raise exhaust gas temperatures on a diesel is to load the engine. This means using the highest gear possible. Happily, this also gives the best fuel economy. You don't need to short shift, revving whilst accelerating is fine.

Good luck.

P.S. You can easily test for fuel dilution in the oil with a blotter paper test. Simply press the tip of the dipstick onto a piece of unwaxed white card. Don't allow the part of the card with the oil spot to touch a surface for at least twenty minutes (use a roll of sellotape or similar prop to suspend the card horizontally). Fuel dilution is manifested by a distinct halo around the edge of the oil spot. Put a drop of fresh engine oil onto another card for comparison. If fuel dilution, excessive oxidation, of lack of soot dispersion is present in the used oil, the difference is obvious.

So, you asked the opinion of the good folks on here...and the almost unanimous response was 'avaoid it like the plague'. Yet you have still bought the vehicle!!!

I am so glad that I didn't offer my services to go with you to inspect the vehicle - seems good advice can sometimes be a wasted effort.

All i will say is good luck with your new car... If the DPF fails to live up to expectations, please think back to all those people who told you to avoid it and the possible repercussions when you post again on here to the tune of 'we told you so'.

BTW, if the vehicle was fitted with a DPF as OE and it has been removed, then I believe it can fail its MOT as it is non standard.

Robin the Technician - I fix therefore I am