POSTED BY: PETER CASSIMATIS - BRISBANE - QLD - AUS  20 NOV 2008   PROVIDE FEEDBACK

========== ORIGINAL POSTING ==========
"HOLDEN ASTRA AH CDTI 2007: DIESEL AUTO PROBLEMS WITH DIESEL PARTICULATE FILTER (DPF) - I'm wondering if anyone else out there has had problems with their Astra CDTi auto that is fitted as standard with a DPF (Diesel Particulate Filter).

Apparently about every 500k's which is virtually every tank of fuel as ours does about 600k's per tank, the on board ECU detects that the DPF has caught an amount of particulates from the exhaust sufficient to increase back pressure in the system. The ECU then over-fuels the engine deliberately to increase the exhaust gas temperature to over 600 deg and this in turn burns off the particulates and the whole operation is "supposedly" more friendly to the environment. However, when this burn takes place it increases the engine speed and in some cases has made the car very difficult to stop and when it does stop the engine "hunts" from 700 to 1400 rpm and does not settle to an idle.

It has been back to the dealer about 6 times in 18 months and we're aware that there are other vehicles they are having problems with. They have loaded the latest software and constantly updated it as required but it has all made no difference. When we use biodiesel the problem is significantly reduced because biodiesel produces less soot and the DPF takes longer to fill up. If any one else has had this problem please advise even if it hasn't been rectified. Thanks."
POSTED BY: DENNIS WIFFRIE - LILYDALE, VIC - AUS 15 OCT 2008

========== REPLY ==========
All new diesels fitted with particulate filters are very fuel and OIL specific. Very few oils meet the latest specs. If you check with Castrol, Mobil etc you will note that they specify specific oils for vehicles fitted with particulate filters. VW have very strict recommendations for their models. The manual Astra Diesels have a different engine and no DPF fitted.

I contacted 2 Holden dealers and enquired what oil they used for servicing diesels and they both quoted just the regular fleet generic grades. Maybe this is what’s causing your filter to foul so often.

Try getting an oil and filter change using Castrol Edge 0-40 or Mobil 1 0-40 and make sure that they only put in the required 4.3 litres as over filling can also lead to fouling EGR valves and DPF's. Finally use only main brand diesel i.e. BP Shell etc. Be aware that problems with DPF's are occurring with all makes world wide.
POSTED BY: GARY BRYANT - SYDNEY, NSW - AUS 17 OCT 2008

========== REPLY ==========
With DPF's it is a good thing not to drive a diesel with one softly (grandma style) all the time. This will clog up the filter. Every now and then give it a bit. It won’t hurt it but it does it the world of good. At Mazda they say the old slow drivers are the ones coming back in with problems."
POSTED BY: ANDREW - SYDNEY, NSW - AUS 20 OCT 2008

========== REPLY ==========
Peter, a short note on the Oil.

ACEA C3 type oil is usually specified for a DPF.
Castrol Edge 5-30 isn't C3 class but Castrol SLX professional OE is.
C3 is lower in ash and S.A.P.

Your dealership should know this but I wouldn't count on it, check with your oil rep. I don't think the motor industry has developed the DPF systems properly yet and the customer is suffering.

Regards, Al
POSTED BY: AL - CAIRNS, QLD - AUS 21 NOV 2008

========== REPLY ==========
Peter, as per Gary's comments in this post and others I had gleaned from Europe I did indeed change the engine oil to Castrol Edge 0-40. The difference to the engine was immediate in that it ran smoother and the behavior of the engine during DPF burn off was greatly improved, dare I say it even acceptable! However, changing the engine oil did create another problem which "feels" like turbo lag. When the car changes gear there is a hesitation in power for about 1 second, this did not happen with the old Mobil Delvac engine oil. Are you saying that by changing to the Castrol Tranzmax Z you eliminated this problem? Also what result do you achieve by using Chemtech Diesel Power?

Thanks Everyone for your Comments.

P.S. Holden are making a concerted effort to help me and 2 other Astra CDTi Auto owners solve these problems. If we can get an acceptable result hopefully then the knowledge will be shared amongst the Holden dealers around the country and anyone else having these problems is just a service away from having them fixed. I getting the lend of an engineers ear next week, I'll post the results here in about a fortnight! Wish me luck!
POSTED BY: DENNIS WIFFRIE - LILYDALE, VIC - AUS 21 NOV 2008