SLK55 AMG engine fans

[Oldandcynical]

Hi, I have a 2012 SLK55 AMG which has in the last couple of days seemed to have developed an engine fan issue, it’s constantly running from as soon as I start the car until I turn it off, has anyone else had similar issues at all.

[trevalvole]

Given that the weather has generally got warmer over the last few days, does it make any difference if you turn the air con on and off?

[Oldandcynical]

Good point so I went out and tested it, within 10 secs of it starting the engine fan comes on even from stone cold. Doesn’t matter if aircon is on or not.

[595Heaven]

I suspect it is an engine temperature sensor that has failed / given an implausible reading. Most engine management systems will default the fans to full if this happens to protect the engine.

Is the MIL light on? Have you got a scan code reader? They are dirt cheap nowadays and will probably show a code.

[0a]

My SLK55 needed the sensor in the fan unit doing. Annoyingly it’s an SLK55 part, so not cheap like the standard Merc bits and it is the whole fan unit rather than the sensor.

[Oldandcynical]

595Heaven said:

I suspect it is an engine temperature sensor that has failed / given an implausible reading. Most engine management systems will default the fans to full if this happens to protect the engine.

Is the MIL light on? Have you got a scan code reader? They are dirt cheap nowadays and will probably show a code.

No lights showing anywhere no, I’ve not got a reader but it’s having a service week after next so I’ll ask them to have a look when it’s in.

[Oldandcynical]

0a said:

My SLK55 needed the sensor in the fan unit doing. Annoyingly it’s an SLK55 part, so not cheap like the standard Merc bits and it is the whole fan unit rather than the sensor.

Really…….ouch

[Oldandcynical]

A further development today, as it’s been a bit warmer I turned the air con down to cold (it’s always on but at about 17) and it wasn’t really blowing cold at all, could well be related to the engine fan issues.

[clarki]

0a said:

My SLK55 needed the sensor in the fan unit doing. Annoyingly it’s an SLK55 part, so not cheap like the standard Merc bits and it is the whole fan unit rather than the sensor.

Yup, mine needed the same.

[Oldandcynical]

It’s in tomorrow, I’ll report back

[Oldandcynical]

Report back from the garage, it’s the Aircon pressure switch and a couple of seals which have failed. Stick in a regas and it’s all good to go for around £200

[595Heaven]

That sounds like pretty good news!

[Oldandcynical]

595Heaven said:

That sounds like pretty good news!

Yeah that could have been a lot worse than that.

[Oldandcynical]

Picked the car up and everything is running absolutely fine so thanks for the pointers everybody.

[0a]

Great news, there are some AMG specific parts, which are more expensive, but there's a lot normal SLK in there as well like sensors and suspension parts.

I had to do a big service on mine and some work on the rear suspension last week. Total bill was £750. Details here: https://www.pistonheads.com/gassing/topic.asp?h=0&...