The fans on my 2007 mondeo 2.0 140 bhp diesal seem to come on when the car is at normal operating temperature. My commute to work is a 4 mile trip up the local by-pass and I normally do about 70, I don't end up sitting in any traffic. I have started to notice occasionally that the fans are on when I get to work. Also there seems to be a louder exhaust rumble and if reved hard lots of black smoke comes out of the exhaust. Also the rev counter doesn't seem to fall smoothly. This all happens when the fan is on. The car wil do this for a few days then won't do it for a couple of weeks. The car still drives the same ie no loss of power, fluid levels are ok. Any deas of what to check first?

Cheers

 

Sounds like it is regenerating the Diesel particulate filter.
Quite normal that the fans are driven.

However, lots of black smoke is not normal.
You could try a longer trip (about half an hour) at higher rpms (lower gear) to properly regenerate the DPF. 4 mile trips are just to short for modern-day diesels.

 

Cheers for that. I'll take it for a blast and clear it out. It also makes a strange groaning noise ( almost like a cow mooing ) when you turn it off?

 

They do make sure strange sounds - The heater makes a groaning noise occasionally, as does the EGR valve (it's supposedly self cleaning as it does a full 'sweep')

It shouldn't regen every couple of weeks unless there's a problem. Do you drive the car very gently? If so, that's the worst thing you can do with a DPF equipped car - you really need to kick the crap out of it from time to time.

Do you have the aircon on? That can make the fan come on.

 

It gets a good spanking at least one or two days a week as I'm usually on the last minute for work. Na don't really use the aircon much

 

hi i have a 2.0 tdci 140 titanium from new and it does the same thing ( without the black smoke ) from time to time and yes it is a regen , it will do it more frequent with short journeys . i find giving it a good "thrashing" on a long journey solves it