Over Heating C220 Elegance Auto

[Manjac]

Hello, I can drive around all day long & the car runs fine, BUT if I get into slow traffic or standing traffic the raddiator starts to overheat. I have changed the thermostate and flushed out the engine and radiator. Also the fan seems to be running free. I was going to put an extra Electric fan in front of the rad to run on a switch, but thought I would ask on here if anyone else has had this problem. The car is a Mercedes C220 Elegance, Petrol, Auto, Year 1996 genuine 540000 miles. Thanks in antisipation
Jack

 

[Ellsy Tanners]

Your viscus fan is most likely knackered. it is designed to cut in when the engine gets hot.

You can do the carrot test.

Stop the fan with a piece of carrot and run the engine until it warms up, when the temp gets up about 100 the fan should cut in and snap the carrot and spin locked in. if this doesnt happen then the oil/wax will have leaked out of the fan and a new one is required.

 

[Manjac]

Thanks Ellsy, I will try that.

 

[Parrot of Doom]

If you don't have a carrot, see how long the fan takes to spin down when the engine is turned off (when hot). If it stops immediately it should be fine, if it takes a few seconds to spin down its on its way out.

Does your car have the 2 auxilliary electric fans? They should click on and off in traffic.

 

[Manjac]

No, not that I am aware of I made a mistake with the milage to many O's only 54000 from new, but it is 12 years old and one way and another all I have put on it since new are two front disc's, two front tyres, Thermostat, one relay, 3 batterys all new, and when it was 3 years old somthing on the air flow that cost £10 to have fitted and £1000. to have made at the factory so not bad after 12 years.

 

[Aussie Nick]

All bears witness once again to the fact that the 202 is a great car.
Just wondering have you checked you engine oil colour as a precaution?

 

[Manjac]

Just done the carrot test temp went up to just over the 100 carrot still there but then fell out. was easy to stop the fan again with the carrot. Also when engine was turned off the fan kept spinning. So presume Viscus fan kaput. Price of new one £140.00. plus fitting does this sound about right?? thanks for all the help guys.

 

[C220GJS]

You can get a fan coupling from ECP for a lot less ; http://www.eurocarparts.com/ecommerce/Search_Results.asp and any competent mechanic should be able to fit it in less than an hour,no need to remove the radiator.

 

[FIBAMAN]

All bears witness once again to the fact that the 202 is a great car.
Just wondering have you checked you engine oil colour as a precaution?

Wish I had kept mine, sold it two years ago with 204,000 miles on clock, still on original clutch. It is still in the family and running no prob. Dont ask me about the E class I replaced it with.

 

[FIBAMAN]

54.000 miles seems a bit low compared to what I got (95,000). But the 12 years could be a clue to my failure theory, (thinkin outside the box here).

On the back of the viscous unit is a (I assume) bi metallic strip which acts on a pin and pushes it into the housing, does this in some way control, for instance, an orifice size which in turn controls the resistance of the fluid. I noticed on both the units I changed (95,000 and 187,000 miles) that the pin was a bit corroded . Could it be sticking? and therefore losing contriol. I did keep one and soaked it in WD40 to play with later, but somehow never got round to it.

Any one else got any idea why they fail?

 

[Manjac]

Thanks C220 GJS. Quite a bit of a saveing only £69.00 as against Merc's £140.00 I am a retired Panel Beater and still have my old tools so might have a go myself. How do you lock up the spindel to unscrew the Fan Coupling. or would I be safer getting a mechanic to do it. lol.

 

[Ellsy Tanners]

its just the big nut on the back of the unit than holds it to the water pump.

I thing its 34mm or 36mm. check which direction the unit spins as i am sure its left hand tread!!

Then hold the spanner and bash with a hammer to shock release it and then spin off.

sounds easy but can be very tight some times. give it a go and if you can do it let some one eles have a bash, shouldnt cost much 10 mins to do really!!