CLK350 05 W209 Temp Gauge Fluctuates

[mydan99]

Hi All,

Before i describe my issue and seek advice, i have extensively searched multiple forums about the issue i am having but i am not entirely sure what the fault might be - i am hoping someone has faced the symptoms before and fixed the underlying issue.

I have a 2005 CLK350 with the following symptoms (see youtube video to see issue in action taken in Dec 2018)

- temp gauge fluctuates, increasingly more in traffic and slow speeds, varying from 110c down to 60c sometimes. This will rapidly go up and down.
- the above issue seems to be a lot more prevalent in summer
- error on dashboard shows "Coolant visit workshop"
- when the error on dashboard shows, the AC fails to deliver cold air but when there is no error, the AC works perfectly fine
- I've checked fuse 51 as mentioned in some threads
- i believe the fan does work. There are some weird times when i use the car (e.g. to go shopping) and when i return and put ignition on position 2, the fan in the engine bay is running at full speed

I have been on long drives without facing this error at all but as mentioned it happens a lot more in hotter weather.

Im leaning towards the issue being a form of sensor based on the temp gauge (see video).

Anyone have any advice for me please? I am wanting to change the coolant and if i have to open up the car i can try and tackle two in one.

Thank you in advance.

 

[AMGeed]

I too would suspect a faulty water temperature sensor.
Ideally you need to take the car to a Mercedes independent mechanic (indy) who will have the diagnostic tools to determine the fault.

I don't now of any recommended in W Sussex, but along the coast at Horndean there is a very good indy at PCS.
Might be worth a call for advice there first.

https://www.prestigecarservice.co.uk/

 

[mydan99]

Thank you - I've used In Autos who are based in Lingfield. Not the cheapest independent but very knowledgeable and easy to deal with.

I need some servicing done so I'll get them to check and advice.

If anyone else has any experience of this, would be good to hear your experience.

Sent from my ONEPLUS A6003 using Tapatalk

 

[EmilysDad]

I'd take a gamble & change the sensor. It's very likely to be a lot cheaper than a diagnostic session at an indie/dealer

 

[mydan99]

You're right . Spoke with Indie and they want £65 to do an hour's worth of diagnostics.

Do you have any idea how to replace the part .I've come across a YouTube video based on annotated pictures and it seems to be on the back of the engine quite hidden .

This would be for the M 272 engine .

 

[EmilysDad]

...

Do you have any idea how to replace the part . ...

Sorry .... I don't

 

[mydan99]

Cheers no worries. I will try a few local mechanics that our family have used and quote from another independent based in Horsham - they have fairly decent reviews on Google.

Will post an update after work is done. Won't be soon as I'm off on holiday in a few days.

Sent from my ONEPLUS A6003 using Tapatalk

 

[EmilysDad]

.... as I'm off on holiday in a few days.

....

Have a good one