[JonB2305]

Hi All,

Firstly a bit of background. I drive a 56 plate E90 325d with 65k on the clock. I'm trying to get my DPF to regen due to 480A and 481A fault codes. I have activation faults codes for all 6 glow plugs so I'm going to change the glow plug controller and test/replace the glow plugs as necessary. I'm also going to change the main thermostat (I've already done the EGR stat).

My question is, while I've got the engine apart is there anything else that you would recommend, either DPF related or general maintenance?

I was thinking maybe blank off the swirl flaps and change the inlet manifold gaskets. I checked the EGR valve when I changed the stat expecting to see thick tar/coke residue but it was basically clean so I'm hoping the rest of the engine will be fairly clean too.

This is my first diesel car so any advice is greatly appreciated!

[Aragorn30d]

I did the swirl flaps and manifold seals when i did my glowplugs. The swirl flaps were leaking oil so i was glad i had the bits to delete them.

FWIW, i changed all 6 glows and one remained faulty afterwards (5 were faulty before) I'm not sure if i just got unlucky and one of the new ones is dead, or if theres some other issue.

The DPF seems to regenerate just fine with the glowplug fault though.

Coolant temperature is usually the primary culprit. My car wouldnt get above 60c and thus wasnt regenerating. I replaced the main stat and now it warms up, but it takes ages and floats around high 70's low 80's so i'm going to to the EGR stat next.

Get yourself a Bluetooth dongle and Torque app, and that way you can monitor the coolant temperature on a run and see what its doing.

[PAULDON]

Id replace all x6 glow plugs anyway, as they are so prone to failure and they are not so expensive (be sure to put a little copper grease on the threads to aid the next guy) and use a torque wrench to fit.

[JonB2305]

Originally Posted by Aragorn30d

I did the swirl flaps and manifold seals when i did my glowplugs. The swirl flaps were leaking oil so i was glad i had the bits to delete them.

FWIW, i changed all 6 glows and one remained faulty afterwards (5 were faulty before) I'm not sure if i just got unlucky and one of the new ones is dead, or if theres some other issue.

The DPF seems to regenerate just fine with the glowplug fault though.

Coolant temperature is usually the primary culprit. My car wouldnt get above 60c and thus wasnt regenerating. I replaced the main stat and now it warms up, but it takes ages and floats around high 70's low 80's so i'm going to to the EGR stat next.

Get yourself a Bluetooth dongle and Torque app, and that way you can monitor the coolant temperature on a run and see what its doing.

What size swirl flap blanks did you use? From what I've read it seems to be a bit of a grey area whether they're 22 or 33mm for my age of car. I guess I won't know for sure until I've got the inlet manifold off.

I read somewhere that the DPF won't regen if more than 3 of the glow plugs aren't working. It seems pretty suspicious to me that all 6 have gone at the same time so I assume that the controller has gone pop. I'll take Paul's advice and change all of the glow plugs anyway to be on the safe side.

Coolant temp wise I was hovering around the 70-73C range. I changed the EGR thermostat earlier in the week and took it on the motorway keeping revs in the 2000-2500rpm range and it was hovering around 79-83.

I changed my front discs and pads yesterday and when I was bedding them in I saw the coolant temp get up to 97C and exhaust temp around 425C so I'm thinking maybe the main thermostat may be ok, but that was fairly extreme rapid acceleration and hard braking. I've already bought the replacement stat so I'll fit it anyway.

I'm tempted to try to get the car really hot again and then take it for motorway run and see whether that'll kick start a regen.

[Aragorn30d]

Mine was the bigger later revised ones (2006 M57).

As i understand it, ALL E90 M57's got the revised swirl flaps. The 4 cylinder cars are less clear cut.

Well as i say mine had 5 broken when i bought it, and from the diagnostics appeared to have managed a regeneration on the motorway while driving home.

The problem with the stat is that they dont close properly. So when engine load is low, they let too much water pass thru to the radiator which results in it being overcooled. Your low wandery coolant under low to medium load is a typical symptom of a stat which is not closing properly.

The DPF does have a finite life, the service interval is around 80k for its replacement! If its near the end of its life, you might well find the regen will be impossible. I think if soot loading is too high, the ECU wont start a regeneration because its deemed "too-far-gone"

I believe if that happens you can use the diagnostic kit to force the car to regenerate. But even then it might refuse. If you have a search on the forum theres quite a few threads discussing it. I'm sure i remember one thread where the ECU kept refusing, or aborting the regeneration, and the chap managed to get it to work by just repeatedly clicking and clicking the force regen option until eventually it kicked in properly and ran thru the process.

[PAULDON]

Or you can just drive to London and back in 4th gear, that's how I got mine nice and clean. 500 miles at 3k rpm , gets it nice and hot and burns all the soot away. Just monitor it on the torque or carly app whilst you drive, it's pleasing to watch the ash/soot content reduce as you drive. Got some extra umpf too when clear. :-)

[Aragorn30d]

High RPM in a diesel will do little to get the engine hotter.

Load is fixed by the speed and road conditions your driving at, so sitting on a motorway at 70 your producing about 30hp just to overcome drag and thats it. That 30hp requires a fairly fixed amount of fuel, and that fuel is what generates the heat.

At 3000rpm the volume of air flowing thru the engine is much greater, because diesels dont have throttle plates. But your injecting more or less exactly the same amount of fuel as you would be in 6th gear, as you need the same amount of power (maybe very slightly more as the engines less efficient)

As a result you'll potentially end up with LOWER EGT's than the same load at 6th gear, due to the cooling effect of the larger charge in the cylinder.

Just drive the car normally. You dont need to do anything special to get it to regenerate, so long as the prerequisites are met. If the prerequisites arent met, driving along at 4500rpm isnt going to help.

The primary issue is that with certain fault codes present, the ECU will not automatically initiate the regeneration. Fix those codes and ensure the engines reaching operating temperature and you'll usually be fine.

[PAULDON]

Well it cleared mine to nearly empty, and that's exactly how i cleared it. Lots of inner city short trip driving will clog up the DPF a lot quicker than long runs up and down the motorway, as it wont regenerate. I had been doing a lot of inner city driving for around 8 months, DPF light came on, so drove 500 miles in 4th gear and completely cleared my DPF (i monitored live it on BMWhat)