Faulty MAF?

[JohnnyW202]

Whilst my C200 is off the road for some major-ish maintenance...

I just wondered, sometimes when sat in traffic the temp creeps upto about 100-110c, it never gets into the red (120) and has never overheated before.... even on 30c days. Thing is when the car gets past 90c I'm anticipating for the fan to come on, being a 1999 mine's electric not a visco-coupling one.

The fan definately works, it comes on slow (Half speed) when the A/C is turned on.

Interestingly enough if I unplug the connector from the MAF, the fan runs at full speed continiously, so the fan does have the facility to cool the engine and maintain a steady 90c like I'd expect....

Could the Air Intake Temp Sensor in the MAF be knackered, or is it just because the engine is going into safe mode and thus the fan kicks in for protection.

Anything to check? Fan Relay, Control Unit? Or just leave as is?

 

[Tinkerer]

Can't see the MAF affecting cooling temperature, got a feeling there is a separate coolant temp sensor to bring in the fan but unfortunately don't know where it is. Perhaps someone else will come along who does.

 

[AMG19]

No the MAF is not knackered it is as you mentioned just going into safe mode.

 

[BlackC55]

At 100DegC the fan should run at around 100%. Does it do this?

 

[JohnnyW202]

No it does C55 Black... and the fan is pretty loud at full speed, so I suppose I'd be able to hear it, when it did kick in. P.S is there a cheaper way to get access to Star? I'd love to see what sporadic codes there are logged in my 202, just to make it tip top if there are any outstanding issues, but I don't fancy paying £50 just to get her plugged in or paying for a multiplexer and laptop at circa £1000.