Engine: D5: MPG down! Oil consumption up!! DPF?

[Chauffeurdude]

Not doing very well so far!! Dealer diagnosed Lambda sensor which has been replaced. This was causing problems with regeneration as I suspected. System is back working again now. They have tried 2 forced regenerations and the readings have got worse so time for a new DPF. To say I am unimpressed is understatement of the year!! As previously stated I don't mind having to spend some money but potentially this could have wrecked my engine. I am worried about the longevity of the engine as appears to have had diesel dilution in the oil for some time!!! Looks like will have to change oil and filter several times in quick succession and hope for the best!! I will be writing a very strongly worded letter to Volvo about this DPF fiasco. Should have the car back tonight or most likely in the morning. Will keep you posted. Cheers.

[Chauffeurdude]

Got the car back on tuesday morning. Seems fine. Done about 200 miles so far on local contract runs and mpg is showing 43.1 at present. Seems to be running smoother aswell now. Got to go to London tomorrow so will see how it does on the blat down the M40!! Ended up with well over £1200 bill by the time dealer had finished, bit heavy on the pen I think!! DPF itself was £500 + VAT and the lambda sensor was £220 + VAT. Got all the latest software upgrades now and has cured the intermittent anti skid service light problem so thats a bonus!! Anyway at least it is back, just got to keep an eye on the oil consumption. Going to change the oil and filter again as am sure oil was being contaminated by lack of regeneration. Thanks for all advice offered.

[5cilinder]

Hold your horses in thinking that your problem is solved
Your symptomes are solved

That oilconsumption DESPITE adding excessive amounts of biodiesel adding to the oil
So the adding of diesel masks part of the oilconsumption
In reality the massive burning of oil could saturate the dpf with ash wich triggers more regenerations because of the less space for soot accumulation
That affects fuelconsumption
Now with the new dpf regeneration frequency goes down also the fuelconsumption
The broken lambdasone could be caused by excessive oilconsmption

Keep track on your oilconsumption if that stays high and not solved then the dpf can fillup with ash again
Check the compression on the cillinders
Check radial play on the turbo bearing

In case the dpf gets saturated with ash dont buy a new one!
Do a forced regeneration to burn the sooth wich leaves only ash
Take the cooled down dpf from the car and use compressed air in counter direction with the other end in a vacuumcleaner bag tied down
If that dont remove enough ash use pressurized water
Reset the ashcounter in vida and th dpf is useable again

[Chauffeurdude]

Thanks for the reply. I am not presuming the problem is solved. I am of the same mind as you about the worrying oil consumption and the fact that this could wreck the new DPF!! Having now done 600 miles since getting car back on tuesday I have just checked the oil and level is where it was when I got the car back. That is very promising!! However I am not counting my chickens and will do an oil and filter change again on monday just incase there was any further contamination. Will monitor the engine carefully over next couple of weeks. Hope all is okay as got plenty of distance jobs in run up to Christmas!! Cheers

[5cilinder]

If the oil is not that old oilchange is not needed the oilconsumption and adding oil is a continious freshing up of the oil

[Jim314]

I don't think changing the oil again right now would be beneficial. It would be a waste fresh oil and a new filter.

[Bill_56]

Originally Posted by Jim314

I don't think changing the oil again right now would be beneficial. It would be a waste fresh oil and a new filter.

I agree.

A DPF-equipped car, even when functioning perfectly, will suffer from oil dilution by diesel, it's an inescapable side-effect of DPF technology.

Volvo's argument, based (IMHO) on unconvincing science, is that it won't affect engine wear. Many people, myself included, are sceptical. But if it worries you that much, the only solution is to buy a petrol car instead.

That said, OP's DPF car has done 250k miles... on that basis, I'd find it hard to justify my scepticism, and maybe even inclined to think Volvo may be right!

Either way, with a DPF diesel, there's not much point worrying about oil dilution, and no point in trying to fight it.

[Chauffeurdude]

Yes you are probably right, maybe I should leave the oil for a while. Just worries me thats all. This is one aspect of diesels that I do not like, the oil in my old Range Rover Classic stays relatively clean for 4-5000 miles between changes!! Admittedly it runs mainly on cleaner burning Lpg but it doesn't 'destroy' the oil like the V70 seems to!!!

Anyway done just 1000 miles since had it back on tuesday and the average on computer is sitting at 45mpg for relatively local work. This is better than had been for some time anyway so there must have been a problem brewing for a while! I have not felt it regenerate as yet but there have been a few dubious burning type smells at times!! Will have to watch out for sudden drops in mpg on computer just to make sure!!

[Duncan L]

Any update on the situation?

I have similar issues with a S80 D5 185BHP now at 171K. Lives it's life on the motorway so I was suprised to see Soot Filter Full intermittently over the last 2 weeks. Also using some oil. Fuel consumption doesn't seem to have dropped much.

Got the Engine System Service message last night and reduced power.

Off to the dealer Thursday.

[outnumbered]

you can have the Dpf removed for less than that price