Cooling Fan blowing like a tornado - new car

[alistairgd]

New W204 C-Class 1800 miles, tonight it starting making a loud noise clearly audible from the inside, near the end of a short journey. Sounds like the cooling fan has gone into overdrive.

Went back out 15 minutes later for a short drive and it still has not gone off. It's only 10 degrees outside and it's only done 2 short journeys today, no need for the fan to be howling like this.....

Any ideas?

LINKS IN MY POST HAVE BEEN ADDED BY THE FORUM AND ARE NOT MINE OR RELEVANT TO THE POSTED ISSUE :O(

 

[sinewave]

Have you got the A/C on Demist?

Does Blow Force 10 if so.

 

[bdman]

I had an identical problem - posted my solution here.

http://www.mbclub.co.uk/forums/electronics/143156-clk-320-w208-aircon-engine-fan-problem-solved.html

 

[alistairgd]

I had an identical problem - posted my solution here.

http://www.mbclub.co.uk/forums/electronics/143156-clk-320-w208-aircon-engine-fan-problem-solved.html

I prised open the aircon housing wooden cover using a slim flat screwdriver and then unscrewed the two housing screws that hold the unit in place.

Then I pulled out the unit and realised that the connecter that goes into the back of the unit was loose

Hmm, could be that, now I have to decide whether I want to have at it on my brand new car with a screw driver, or drive it 45 miles to the dealer. On Monday.

Where is the aircon cover, easy to access?

 

[bdman]

Hmm, could be that, now I have to decide whether I want to have at it on my brand new car with a screw driver, or drive it 45 miles to the dealer. On Monday.

Where is the aircon cover, easy to access?

On my car its the wooden veneer above the CD player that covers the air con control unit... Not sure where it would be on your brand new model!

But if you do take it to the dealer make sure you tell them to check the connectors thoroughly so they dont take you to the cleaners and start replacing thermostats and engine fan parts first..

 

[alistairgd]

There will be no cleaners involved, Warranty won't be a problem.

I'm phoning first thing and they can let me know if it is okay to drive it in or if I should invoke recovery to prevent any damage or premature wear. I will mention the connections though.

Also, I notice that the temp gauge on the dash is not working properly. When the engine is hot, it is ready stone cold on a restart - don't think it did that before.

 

[jaymanek]

The cooling fan coming on full force is usually indicative of a fault.. mostly a communication error between two modules on the car.

Either way, poking around behind the dash is unlikely to solve the issue, it needs to go to the dealer if its still under warranty.

 

[panason1c]

Sounds like an ecu fault, definately one for the dealer to sort out.

 

[alistairgd]

Took it in today, they put it on diag. and the report came back with one stored fault, something about coolant temperature, which makes sense.

They cleared the fault and the issue was gone.

But they also showed me about 7 other lines on the report, not stored faults, but stored issues, lots of small percentages, and something about the throttle. I was told if the fan issue came back again, they would have to look further into all these details.

So fixed, but not entirely happy.

 

[bdman]

Good to hear it was fixed buddy

Took it in today, they put it on diag. and the report came back with one stored fault, something about coolant temperature, which makes sense.

They cleared the fault and the issue was gone.

But they also showed me about 7 other lines on the report, not stored faults, but stored issues, lots of small percentages, and something about the throttle. I was told if the fan issue came back again, they would have to look further into all these details.

So fixed, but not entirely happy.

 

[dog68]

Took it in today, they put it on diag. and the report came back with one stored fault, something about coolant temperature, which makes sense.

They cleared the fault and the issue was gone.

But they also showed me about 7 other lines on the report, not stored faults, but stored issues, lots of small percentages, and something about the throttle. I was told if the fan issue came back again, they would have to look further into all these details.

So fixed, but not entirely happy.

So really.. its not fixed then?

 

[jaymanek]

You will need to change the coolant temp switch by the sounds of it, it will only come back.

Dont worry about the stored codes, unlikely they will come back.

 

[alistairgd]

So really.. its not fixed then?

The fan isn't in overdrive anymore, but no they never "fixed" anything, just deleted a logged fault on the system. The reason behind the fault that led to the issue remains unresolved.

 

[alistairgd]

You will need to change the coolant temp switch by the sounds of it, it will only come back..

Yeh, something like that is obviously on the way out, but until total failure it's a waiting game.