Service Issues: DPF Soot filter full

[jamie1131]

I had this problem with my '07 XC90. It was burning a horrendous amount of oil causing a big soot build up.
Are you confident that the DPF is actually blocked and that it is not a sensor giving a faulty reading?

[Hank3944]

Hi i cant be sure, but the fact my inlet maifold is clogged with carbon suggests the problem is elsewhere, do you think an engine carbon clean using added hydrogen would help apparently the hydrogen vapourises the carbon build up,

What i am thinkng as a next course of action is: carbon clean, £100, dpf clean £200 (although already had forced regen and reports come back soot empty) oil and filter change (last changed 13 months ago) so due and see if this works, then start changing sensors, what do you think guys does this sound like a sensible plan?

[SwissXC90]

I would suggest in this order:
1. Record all DPF filter pressue values (print to PDF from VIDA) and fuel trim values as a baseline
2. Oil+Filter change
3. Clean soot-filled intake manifold and EGR components
4. Record new pressure values and fuel trim values, test drive for a week
5. Determine if any further action needed such as external DPF clean, replacement of sensors, etc

You really need to know where the soot is coming from: oil, or too much fuel?

[Hank3944]

Originally Posted by SwissXC90

I would suggest in this order:
1. Record all DPF filter pressue values (print to PDF from VIDA) and fuel trim values as a baseline
2. Oil+Filter change
3. Clean soot-filled intake manifold and EGR components
4. Record new pressure values and fuel trim values, test drive for a week
5. Determine if any further action needed such as external DPF clean, replacement of sensors, etc

You really need to know where the soot is coming from: oil, or too much fuel?

Swissxc90 i cant thank you enough, this sounds like great advice. I am going to do this. I will let you know what the outcome is. 😀👍🏼👍🏼👍🏼

[osullivant]

Originally Posted by Hank3944

Hi i cant be sure, but the fact my inlet maifold is clogged with carbon suggests the problem is elsewhere, do you think an engine carbon clean using added hydrogen would help apparently the hydrogen vapourises the carbon build up,

What i am thinkng as a next course of action is: carbon clean, £100, dpf clean £200 (although already had forced regen and reports come back soot empty) oil and filter change (last changed 13 months ago) so due and see if this works, then start changing sensors, what do you think guys does this sound like a sensible plan?

If you can do the work yourself I suggest you clean the air pipes to the intake manifold and the butterfly valve, replace the pcv valve on top of the oil separator, use liquimolly DPF cleaner followed by a regen.... drive for a few weeks and see does it settle down.

I have done all of these things and new turbos and new rings and new sensors etc. but I still had the soot filter full until I did the liquimolly clean (I previously had so called professional cleans and some DIY cleans but the LM product was super. Use a garden sprayer from argos with a lance made from some aluminium tube from B&Q to put in the chemicals,

my theory is that the PCV system goes wrong and at high revs instead of closing the connection, the airintake is so close to the turbo that it causes a vacum which draws oil out of the separator and then fires this into the intake..

[Hank3944]

Hi, can you tell me what the pcv valve looks like?
Today i have done an oul change and cleaned the intake pipes aegr housng and butterfly, did a test drive.... soot filter full. Think i might try the pcv valve next, where is it and how much and hard is it to change?

[jamie1131]

Its at the front of the engine near the oil filter housing. There is a hose running from the top of the case, over the engine and into the air intake on top of the cam cover.

you can check if this is your problem fairly easily. get some similar diameter hose from Halfords, a clear plastic bottle (an old coke bottle will do) and some cable ties.
Disconnect the hose from the PCV end, fold it in half and wrap a cable tie around it to clamp it shut. The cable tie will need to be quite tight to make sure it is all sealed.
Connect one end of your new hose to the PCV and the other end into the plastic bottle. zip tie the plastic bottle in a suitable location and similarly zip tie the hose so that it can not come out.

Take the car for a good drive and see if you block the soot filter again. (You'll need to make sure it is cleaned out before you start otherwise you won't know if this has worked or not). Also check to see how much oil has made its way into the clear bottle. Its normally for there to be an oily mist but your shouldn't see much more than spoonful in the bottom of the bottle.

[Hank3944]

On my test drive earlier i got the soot filter full and limp mode after about 2 mns, i tends to happen when you accelerate quite hard, will 2 minutes be long enough to test this method of the coke bottle?

[jamie1131]

If its blocked you need to clean it out, otherwise you wont know if you've fixed it. Sounds like you need to do a manual regeneration with vida or a new DPF. Just fixing the problem on its own won't unblock the filter, if its blocked, its blocked. if it really is blocked, I wouldn't expect the regeneration to work unfortunatley!

Once you have

[Hank3944]

Hi jamie, sorry, if whats blocked the dpf or pcv valve?