Concerned about the DPF on my new car
Discussion
hi all
Bit of an embarrassing question seeing as im 'into' cars
I bought a new used car the other day with a diesel engine. my two previous cars have been petrol's and im new to diesel ownership so go easy on me haha !
ive read horror stories online about the dpf filter clogging up and this has got me concerned. What do i have to do to ensure it doesnt clog up and how often do i have to do it ?
any help or advice greatly appreciated
Bit of an embarrassing question seeing as im 'into' cars
I bought a new used car the other day with a diesel engine. my two previous cars have been petrol's and im new to diesel ownership so go easy on me haha !
ive read horror stories online about the dpf filter clogging up and this has got me concerned. What do i have to do to ensure it doesnt clog up and how often do i have to do it ?
any help or advice greatly appreciated
scrambler95 said:
cheers, once every two weeks on the motorway would you say ?
saab 9-3
On a new-ish car it's not such an issue, as the DPF has been integrated into the manifold and gets very hot very easily. Older designs (i.e. DPFs bolted on to older tech not designed for it, usually far down the exhaust pipe under the car) were a different story. The problem is, unless the car is already trying to actively regenerate, you taking it for a 'hard run' just because it's been two weeks or whatever can actually make it worse. saab 9-3
I had to drive one of the blasted things (2010 Skoda Superb) and you could almost guarantee that after a long journey, for example Liverpool to Devon and back, the DPF light would come on a few minutes from home. It used to drive me nuts! I ended up taking it into the dealership and asking what the hell was going on. Surely after almost 12 hours of hard motorway driving the thing should be emptied and clean as a whistle? Well, no. As the car hadn't decided to clear itself out at the time, my long journey had actually just helped fill up the DPF even more. As luck would have it, that meant the 'you need to take me for a clean out run now please' light came on just after the long run had finished.
Driving at higher revs or one gear down from top on the motorway (and other similar advice often given out in this regard) again just compounds the problem as all you're doing is generating even more particulates than normal and filling the blasted thing up faster and more often! Personally I'd say just drive the thing normally. If and when it ever complains, then take it for a spirited run until the light goes out. Rinse and repeat. You're pissing in the wind otherwise.
My 2013 diesel loves to do this aswell, waits until I get to the motorway off slip, then starts a regen as I approach home. Useless bloody thing, really needs a dial on the dash showing a percentage of how clogged the DPF is getting, so you can push a "regen" button as you get settled into a long motorway journey. Otherwise it always seems to start just as you arrive at your destination.
Its a dilema for most diesel cars this age, if the DPF is functioning (If its a 1.9) it has the same setup as many vauxhalls and Alfas. Motorway crusing in 6th gear at legal speeds is too low rpm to clear the filter and they have more tendancy to clog. If a previous owner has removed it or modified it by coring it out there is a risk a vigilant MOT tester will fail it. However if your sure its working and you regurlarly take spirited medium-long drives and drop it down a cog during regen you should be ok.
Edited by davebem on Sunday 21st January 11:44
Thanks for the pointers and advice. Im aware of the common issues these engines have. apparently the last ones (which ive bought) dont suffer with the swirl flap issue but that could be salesman talk. I well underspent what I wanted to spend on a car so in a few weeks im going to book it into the local saab specialist and just pay to have any work it needs done. I like the car so I dont mind spending money on it haha thanks again guys !
It's not normally the DPF itself that is the issue (unless the manufacturer has gone cheapy cheap on its material and it starts cracking) but the supporting parts of the system.
There's two major ways of regeneration of the DPF happening - this is when the soot is burned off:
1) A vapouriser is placed upstream of the DPF and during a regen diesel is injected in to the DPF assembly and raises its temperature - these can just outright fail and will then stop any regens from happening, eventually meaning the car will throw a MIL due to too high pressure drop across the DPF
2) Fuel enrichment in the cylinders where extra fuel is injected to the cylinder (as a post-injection ATDC) and goes down the exhaust to heat the DPF/oxidised by the oxidation catalyst - these can wash the bores of the cylinders leading to accelerated cylinder wear or fuel in oil issues, where the oil gets contaminated and doesn't lubricate properly.
You can't really do much yourself for the above issues, so just drive the car, and give it some welly sometimes (motorway or high load) to give it a little helping hand.
There's two major ways of regeneration of the DPF happening - this is when the soot is burned off:
1) A vapouriser is placed upstream of the DPF and during a regen diesel is injected in to the DPF assembly and raises its temperature - these can just outright fail and will then stop any regens from happening, eventually meaning the car will throw a MIL due to too high pressure drop across the DPF
2) Fuel enrichment in the cylinders where extra fuel is injected to the cylinder (as a post-injection ATDC) and goes down the exhaust to heat the DPF/oxidised by the oxidation catalyst - these can wash the bores of the cylinders leading to accelerated cylinder wear or fuel in oil issues, where the oil gets contaminated and doesn't lubricate properly.
You can't really do much yourself for the above issues, so just drive the car, and give it some welly sometimes (motorway or high load) to give it a little helping hand.
scrambler95 said:
Thanks for the pointers and advice. Im aware of the common issues these engines have. apparently the last ones (which ive bought) dont suffer with the swirl flap issue but that could be salesman talk. I well underspent what I wanted to spend on a car so in a few weeks im going to book it into the local saab specialist and just pay to have any work it needs done. I like the car so I dont mind spending money on it haha thanks again guys !
It was early models that had it (05,06 IIRC). Mine certainly did, and it took an age for a recall fix.Check on SaabCentral, they normally have accurate info.
http://www.saabcentral.com/
All you need is to give the car an Italian tune-up. Really simple:
1) Drive the car gently, until the engine is up to normal operating temperature.
2) Once up to temperature, drive the car like you stole it, using lower gears than you usually would, at any given speed. If your car is an automatic, bung it in "Sport" mode, or use the flappy paddles.
3) When you're done with driving like a loon, drive the car gently for the last few miles of your drive home.
4) Stick the car on the driveway, with the engine running. Let it run at idle for about a minute, then switch off.
Italian tune-up complete!
Repeat the steps above about once a month.
1) Drive the car gently, until the engine is up to normal operating temperature.
2) Once up to temperature, drive the car like you stole it, using lower gears than you usually would, at any given speed. If your car is an automatic, bung it in "Sport" mode, or use the flappy paddles.
3) When you're done with driving like a loon, drive the car gently for the last few miles of your drive home.
4) Stick the car on the driveway, with the engine running. Let it run at idle for about a minute, then switch off.
Italian tune-up complete!
Repeat the steps above about once a month.
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