XSeries-forum

RE my X 5  4D  M sport  Diesel  I notice  that often when i turn the ignition  off the cooling fan stays  running for 3- 4 minutes, even when i have only driven  it gently at 30 - 40 mph . I took the X 5 into Williams BMW under warranty for a diagnostic check and they gave it the all,clear but now with 18,000 miles  on the clock and the warranty expired,  i notice that this is happening more often  . The main cooling fan stays on even after short journeys, and im not hammering the engine or standing in  traffic queues  so why is this happening ? Anyone know why  or have the same issue?  Never  happened on  any of my previous  two X 5s ??
Williams said  the 4 D  engines  do have different cooling  set ups? Am i being fobbed off  , with a big bill coming up now im out of warranty  with only a low mileage  ? 
Urgent rsvp ! 

Could well be that the DPF is going through a regen cycle.  Mine does it occasionally and the fan running is to keep the heat under control.  It would catch fire otherwise!  You might need to take it for a longer run to get the regen cycle to fully complete.

Richard

Hello Richard
The  DPF ?  Is that the large  cooling fan, just behind the main radiator?  It runs for up to 5 mins  after i leave the car  sometimes  not always, and i worry about the engine CH  temp, as i dont want an overheated  cylinder head. I presume its blowing when im driving as  well but  i  cant hear it when driving and i would have expected the  moving  vehicle airflow through the radiator  being sufficient to keep the engine cool. !
No overheats recorded  by main dealer on diagnostic  check , but you dont know as  BMWs dont have  a cylinder head temp gauge ! ( We  Pilots have a habit of keeping an eye on them due shock cooling and resultant front cylinder head  crack damage ) !
I could understand the fan running  like most cars, if you are stuck in standing traffic after  a hot hard speed run where both turbos are red , then the heat  has to be disapated , but not on short cool runs of  5 miles at 30 mph.
I had an Lotus Esprit Turbo in 1984  and you had to lift the tail gate glass  boot open if you got stuck in traffic  as 3 fans still couldn't cool the Lotus engine at the rear !! May be thats why the engines were only good for  25,000 miles  as heads warped often !
Any one  else with a 4 D ,  X 5/ X 6  experienced  same issues ??

DPF = Poxy device to please the 'lefties' and tree huggers. Diesel Particulate Filter 

Diesel Particulate Filter - a soot trap device in the exhaust that also works as the car's catalytic converter.  Cleans the exhaust emissions and if it gets clogged costs serious money.  Every so often the car heats the DPF by changing the injection timing so adding a bit of fuel and it gets hot enough to burn the soot off.  That means running at up to 600C.  If the vehicle stops during the cycle then the fans keep running in order to prevent damage to the car. 

You have plastic front wings and all sorts of underbody shields so keeping cooling air going it vital.  We have liquid cooling so thermal shock not so much of an issue - unless you pour a bucket of iced water in at the wrong time, which I don't recommend!

You won't normally hear it when driving as the airflow keeps the engine bay cool enough.  In traffic then the fans will cut in just the same way.  Mine has run for up to 15 minutes if I've caught it early in the regeneration cycle.  Typically the regen will run every few hundred miles if most of your driving is town, less frequently for motorways.

Richard

Thanks  for the reply guys,  well that's a perfect excuse  for a motorway blast  to get the full benefit of those  300 plus horses,, " sorry officer  i was just cleaning out my particulates filter at 120 mph........ i wont do it again... well until my cooling fan comes on again  in two weeks time anyway !

You only need to do 40mph for 15-20 minutes sir....not 140.. )

Richard

just reading this post my van occasionally does this? would a transit have a dpf on 08?

By 2008 it was made with EU4 emissions and a DPF depending upon the engine type and options.

Richard