Diesel Particulate Filters (DPF) issues and comments

Mankysteve

Ranger8 wrote: »

To my mind petrol vehicles are the wisest choice for primarily short urban trips.
.

My dad just brought a diesel he reckons that in city driving the mileage is only a few mpg than his old petrol. But as soon as he gets on the motor way that what makes the difference in mileage.

daveyjp

"I was not warned to check the oil for a rising oil level"

Is it in the handbook?

Tha Mazda system is one of the worst out there as AFAIK they are the only ones who designed a system which flushes diesel back into the sump to the extent that it can blow your engine with no warning.

Other marques use oil monitoring systems to check for oil dilution - as soon as the oil needs changing the car lets you know.

vikingaero

daveyjp wrote: »

"I was not warned to check the oil for a rising oil level"

Is it in the handbook?

I have a Mazda 5 diesel and it is in the handbook, but the handbook is so poorly laid out and designed that any warnings aren't sufficiently highlighted.

The main problem with the handbook is the idiot Americanised warnings. For instance to explain the operation of the central locking might involve one page of writing and 6 pages of warnings. I reckon if you deleted all the warning message you could have a handbook 1/3 to 1/2 the thickness.

jodun_2

I have an Audi A4 and recently had problems with the particulate filter. My car is still under warranty (just) so the dealer fixed it no problem. I do a fair mix of short town drives and longer ones, but the guy at the dealership advised me to really 'open her out' every couple of weeks. If I remember rightly it says in my book to drive at 2500 revs for 20 minutes every so often to keep it clear.

Re mileage, I get way more mpg on long runs over about 30 miles, about 12 more than usual.

skiddlydiddly

daveyjp wrote: »

"I was not warned to check the oil for a rising oil level"

Is it in the handbook?

Tha Mazda system is one of the worst out there as AFAIK they are the only ones who designed a system which flushes diesel back into the sump to the extent that it can blow your engine with no warning.

Other marques use oil monitoring systems to check for oil dilution - as soon as the oil needs changing the car lets you know.

Seriously?I don't know that much about diesel engines but even if it doesn't overfill the oil its surely going to cause borewash.So either way you lose.

cepheus

So how is the Diesel getting into the oil, past the piston rings due to backpressure in the exhaust? I would of thought that particulate in the oil would be a far greater problem.

finallycruising

daveyjp wrote: »

"I was not warned to check the oil for a rising oil level"

Is it in the handbook?

Chapter 8, page 28 has a 'note' which says if the engine oil is close to or near the X, the oil should be changed. No mention of what may be causing it or the importance. Surely such a potentially serious issue warrants a stand out warning on its own at the front of the manual?

When I started driving in the 70s I would always check oil levels and such like on a weekly basis. Over the years cars have got more reliable and, until now, I wouldn't think of checking the oil from one service to the next. None of my recent cars have had any problem with using (or gaining!) oil.

P

finallycruising

cepheus wrote: »

So how is the Diesel getting into the oil, past the piston rings due to backpressure in the exhaust? I would of thought that particulate in the oil would be a far greater problem.

There are others who must know more about this, but it sounds like it drains from the DPF if the car is stopped before the diesel has ignited. From what I understand the particles are 'bonded' to components of the DPF so won't wash out with the diesel.

Regarding fuel consumption, it's a 2.0 and averages high 30s on short journeys (probably all that diesel going into the oil!) but have easily obtained 60mpg on a long run.

P

Ranger8

finallycruising wrote: »

but it sounds like it drains from the DPF if the car is stopped before the diesel has ignited. From what I understand the particles are 'bonded' to components of the DPF so won't wash out with the diesel.

No it doesn`t drain from the DPF.
During regeneration extra diesel is injected into the cylinders and ends up in the DPF where it ignites during the hot regeneration process during which the `soot` is burnt off.
If the regeneration is interrupted or halted that excess diesel can get past the rings and end up in the sump.

roysterer

RANGER8
is correct this happens on the Vauxhall Meriva. Because I owned one for six months and now got rid of it. I have owned 2 diesels previously without any problems (pre-DPF).
I WILL NEVER BUY A DIESEL CAR AGAIN.
Unless you are doing frequent long motorway type journies do not buy a modern diesel.
This problem is becoming more and more common just read the AA site regarding DPFs they are getting called out frequently for this problem.
Dont listen to car dealer salesmen they will not tell you the truth.
Google:- Vauxhall DPF and read about all the nightmares people have had with the Meriva's and Zafira's, I learn't the hard way and got rid of my Meriva before the engine blew up!!!!!
Luckily the main dealer mechanic was driving the car when the car broke down during a test drive to establish the problem with the car. He confirmed that the regeneration of the DPF was not taking place as it should have thus resulting in diesel being dumped into the sump. If I would have continued driving the car like this then the engine would have blown up!!!!!!!
AT NO POINT DID A WARNING LIGHT COME ON, (IT SHOULD HAVE). It was only because I didnt feel the car was running as it should have that I took the car in to be checked over. The car was only 2 years old and covered under warranty. Some main dealers will not acknowledge the problem claiming that people continued driving there cars when the warning light came on. Many people like myself never had a warning light come on.

MY ADVICE IS STAY WELL CLEAR (I WISH I DID)