Hi all
At the point of frustration here, so any pointers really appreciated.
Have an 11K mileage/March '09 car which - since a I got secondhand from the dealer in July - has had occasional fan running-type noise after engine switch off, usually after short journeys and can run for anything up to 5 mins. Sometimes (at least) this has been accompanied by blue-ish smoke (which one assumes as oil) coming from the engine compartment, normally escaping via the front wheel arches. On two occasions, the 'engine malfunction' message has come up. This whole process can occur up to 3 times in a week, though is normally once every 7-10 days. The car doesn't handle differently performance wise, even when I can hear the fan noise with window down, at traffic lights, etc..
The car has been to the dealer twice and, with their tendency to use a laptop and not a spanner these days have found no problems (engine codes or otherwise, despite the messages I saw). On the second visit, they told me the fan noise after switch off was the EGR valve, but couldn't explain the smoke. Have recently put a full tank of Shell V-Power into it, should it be a supermarket fuel issue with the EGR.
As this engine isn't just limited to Mondeos, has anyone got any ideas on what to do next?
Many thanks!
Edited by Dynamic Dave on 22/10/2009 at 20:07
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IIRC, the fan runs on after switching off if the DPF is doing a regeneration. this involves the DPF getting very hot and the DPF is behind the engine so if there was any oil spilt or leaking on to the DPF then it would probably burn off as blueish smoke and come out from behind the engine and possibly under the front wheel arches. Have a look down the back of the engine and you will see what looks like an exhaust silencer, see if there is any oil on it.
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My new Audi does the same thing, though minus the blue smoke, and less frequently than you describe. As Kith says, it's almost certainly the DPF regeneration cycle or 'burn-off'. A diet of short runs will result in this happening more frequently. If you keep the revs consistently over 2000rpm (e.g. 70mph on the motorway), then the exhaust temperature will be high enough to keep the DPF clean and you won't (shouldn't) get these forced regeneration cycles.
Did your Ford dealer really tell you it was the EGR valve?!!!
On the fuel question, I'm not sure. It's possible that supermarket diesel might not burn as cleanly and result in faster soot particle accumulation on the DPF. On the other hand, AFAIK the premium fuels such as Shell V-Power Diesel are produced by GTL ('gas to liquid') technology and probably don't contain the crud that comes from crude oil distillation. I've assumed that any advantage of these fuels (in terms of a cleaner engine) is likely to be seen at the injectors, rather than the exhaust end, however.
If there are any fuel experts out there, and I'm talking complete carp, I'm happy to be corrected. And stop wasting my money on premium diesel.
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Yes, it's the DPF regenerating. The radiator cooling fan always comes on when the DPF is doing a regen, and will stay on until the 'burn' is complete. This is to shift the high underbody heat.
The smoke you're seeing is some stray oil that's probably leaked onto the DPF casing.
The reason why it does it to you 2-3 days in a row is because the DPF regen hasn't completed when you switch off. This is why you get the engine malfunction light too, it's just signalling the regen isn't completed.
What that means is, the ECU will start the regen again as soon as the engine hits the predetermined operating conditions to start the regen (i.e. coolant temp above 70 celsius, exhaust gas temp above a certain level, etc etc).
If you don't already do this, I would suggest using 3rd gear in 30 limits instead of 4th. This keeps the revs up around the peak torque, which keeps exhaust gases hotter and ensures less soot build-up in the DPF.
I started doing this in my 2.0 TDCI Mondeo IV several months ago and I hardly ever notice a regen now, it 'self-cleans' continuously much more effectively simply by using 3rd in town instead of 4th.
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Many thanks for your prompt and helpful replies guys - in the back of my mind (having done research on DPF issues that I might suffer with my characteristically short runs to work, though having had two Alfas with DPFs and never having any problems - ironically!) DPF issues were on my mind and I had posed the very same question to the 'dealer experts'.
And yes, the Ford dealer told me it was the EGR valve - even though I told him it was the engine fan running/as loud as if not. Great, huh?
All the best & thanks again
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Skyman, I too have only a short commute to work (3.5 miles each way). Sometimes a couple of weeks will go by without me doing a journey longer than 10 miles or outside urban limits.
In the first few months of ownership of my 2.0 with DPF, I used to get these DPF regens every 2 weeks or so.
But then I started using 3rd gear in 30 limits (4th is really too tall for my liking in town anyway) and only using 6th gear when at 75+ on motorways, and regens are far, far less frequent now.
Also, I can now hear when the cooling fan is on (indicating a regen is under way), so if I'm near home and I hear it, it only needs an extra couple of minutes driving for the cycle to finish.
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