Saab Diesel Particlulate Filter Problems?

Diesel Particle, or particulate, filters (DPF) becoming blocked in the Saab 9-3 is becoming more and more of a problem. This occurs with the cars fitted with the 1.9L Diesel where the filter is fitted, and where the cars are used for repeated short journeys, or spend a lot of time sitting at idle in traffic.

We have put together this article to try to and help folk understand the problem, and, using the tips below ,be able to reduce the chances of their car being affected.

Why do the cars have them?

Simply it is to reduce exhaust emissions.. Since 2006 most Diesel vehicles have them fitted and legislation is in place to make the fitment compulsory to all new vehicles.

What is a DPF?

A diesel particulate filter, sometimes called a DPF, is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. A diesel-powered vehicle equipped with a functioning filter will emit no visible smoke from its exhaust pipe. In addition to collecting the particulate, a method exists to clean the filter. This is known as “filter regeneration”. Regeneration is designed to burn off the accumulated particulate matter. Regeneration takes place, automatically (or passively), on motorway-type runs in which the exhaust temperature is high (somewhere between 350ºC and 500ºC).  As the exhaust is so hot it becomes hot enough to ignite the soot particles.

A surprisingly large number of people don’t take their cars anywhere near a motorway so passive regeneration is only going to be possible once in a  blue moon. We have found the problem has mainly been occurring in cars that are driven short distances, ( school runs etc). As a result the car never really gets hot enough for the cars systems to initiate the automatic regeneration process that cleans the filter. The result is that the filters become blocked, the “check engine “ light comes on and there is a gradual loss of power.

 Replacement of the filter is an expensive exercise, usually in the region of £1000.

Tips to keep your filter clean.

If your car is used for short journeys.

• Every week or so take the car out for a run up your local bypass or short motorway stretch for roughly half an hour at motorway speeds. Occasional harder driving in lower gears should be sufficient to burn off the soot.
• Use a fuel additive that will enable the cars regeneration process to occur at lower temperatures. Diesel particulate matter burns when temperatures above 600 degrees Celsius are attained. This temperature can be reduced to somewhere in the range of 350 to 450 degrees Celsius by use of a fuel borne catalyst.
• Avoid the continuous use of “supermarket” diesel.
• If you suspect the filter may be blocked, a Dealer or Specialist has the computer to carry out a manual or forced regeneration
• In the event of a completely blocked filter we now have some equipment and a treatment that can clean it, which is much much cheaper than replacement. Call us on 01892 825208 for more information.