Not sure whats took me so long to find this forum - i have been fighting my case with Mazda for 1 year and 8 months now. One of you actually noted about the guy with the 62% diesel/oil contamination, that's me. I had a engune run-away whilst travelling on a motorway for about 2 hours, so firstly - the DPF would have regenerated.
The below has been taken from another forum (saves me time), its what i have found out too:
"Firstly, a bit of technical background, for those of you who don't already know ... I've spent the best part of the past month trying to understand DPF's and their regeneration process - Google it yourself if you want - basically, the idea of a DPF is it collects the nasty diesel soot, then USES RAW DIESEL FUEL on the EXHAUST STROKE of the engine cycle to burn it off when the filter gets full - that's the regeneration process. Under a "proper" or "normal" DPF design, the diesel fuel is injected by an injector situated in the DPF itself, where an exothermic reaction takes place with the hot exhaust gases, burning off the soot. So, why is Mazda's system then troublesome? Well, like (apparently) VW and MOST other manufacturers, Mazda does not have a fuel injector in the DPF to do this exothermic regeneration process, but rather uses the EXISTING engine cylinder fuel injector (which in a diesel engine here, is a direct injector into the combustion chamber) to do this raw diesel injection on the exhaust stroke - this system is basically ... you guessed it ... cheaper than having a separate injector system for the DPF. The consequence of this is that because the diesel fuel that is injected upstream in the cylinder during the exhaust stroke (before it exits the cylinder and reaches the DPF) is still raw, some of it slips past the piston rings, and into the crankcase. None of this would obviously happen, if diesel wasn't being injected into the cylinder at the exhaust stroke, but rather further downstream into the DPF itself.
This fuel entering the crankcase past the piston rings is technically known as "fuel dilution" ie. the engine oil gets diluted by fuel.
Another terrible downside of fuel dilution is ... once again you guessed it ... the engine oil deteriorates, causing engine wear. So while DPF is great for the environment (basically it was these regulations that forced DPF's into existence), it's not so good for engine protection ... at least the cheaper versions of DPF."
Whereas i have been fighting this with mazda for this long now, i am now, finally at the stage of an engine inspection which will be carried out by an independent engineer. I am putting all my points across for him to check, no matter what the cost so he can detail in his report that the design of this system is wrong - hopefully it will go for many other drivers facing the same problem with high oil levels due to excess diesel entering into the pan. Its pure WRONG. My aim is to go to court, refuse all Mazda has to offer which have been tempting so far to basically 'Shut up', i am working my bum off before this inspection letting everyone know some more and whether the ones of you who have had similar problems to drop me an email or PM with your issues and experiences.
If i happen to win in court and prove that there is a huge design fault with the DPF systems that causes this oil dilution to occur then i hope for the ones of you that have used money to fix a problem of the manufacturers you can get it back.
Please note, Mazda's response to us that have had these issues mainly comes down to driving styles being wrong, us not checking oil levels, and ignoring warning lights. I must make sure to say that in my cars issue, i have never had any warning lights appear in regards to the DPF or anything that would warn about the engine run-away....The below is quoted from Mazda's head customer service guy:
"I can confirm the vehicles on board diagnostic system does monitor oil dilution and particulate matter, which would lead to warning light illumination"
To conclude this post - at the end of the day the design system is wrong, it should have been recalled & still should. Why would all manufacturers make a new DPF system that uses its own injectors single or duel thats actually placed inside the DPF. This way the car does not use the main injectors/cylinders! what does that mean? No high risk of this diesel coming down the cylinder/injector into the sump from a failed DPF regen or engine wear.
I hope you guys found this useful & if you would like to support me and put your points accross you can do so:
mazda-campaignMember Since 20 Jan 2011
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Mazda - Sorry! :P
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