Overheating 1995 C180

[fouskos]

I have a 1995 C180 with manual aircon.
It has a viscous fan and two electric in front.
If I am not wrong these two are only for aircon (?).
Yesterday I switched on the aircon while I was in traffic and the temp went to 100 -105'C. I have noticed that the two electric fans were cutting in in 105only for 5 to 10 seconds without cooling the engine.

Is that normal?

I would like to notice that I have not seen this ¨attitude¨ before.

 

[television]

Your engine fan is a visco coupled fan that cuts in at 85c, do the carrot test.

run the engine up to the point where the visco engine fan starts to increase or 85c, feed a carrot into the blades,if it stops the coupling is u/s,if it slices it up its fine. The visco coupling cost around £85 quite easy to fit.

Malcolm

 

[fouskos]

Thanks Malcolm,

I have noticed that when I switch on the aircon the aux fans are not cutting in until the temp rises up to 105. Is this normal?

thanks in advance

andrew

 

[Uncle Benz]

I would expect the electric fans to switch on as soon as the aircon is switched on. They should run all the time aircon is on as far as I am aware. If the fans don't run, the aircon condensor will get v hot and heat soak will heat up the coolant radiator quite quickly. I think you have a problem with electric fan switching via aircon system. They will come on under a separate thermostatic switch to cool the engine if coolant temperature rises too high. It seems this part of your system is working correctly.

 

[television]

As Uncle Benz, electric should cut in at 105c.

Malcolm

 

[eric242340]

As Uncle Benz, electric should cut in at 105c.

Malcolm

Yes your auxillary fans shoud come in at 105, however they should come on with the air con, the air con puts extra load on the engine and therefore the engine needs more cooling. Check out the auxillary fan control. The thermo fan appears to be working normally, however the carrot test, and dont try it with your fingers, is worth looking at.

 

[Uncle Benz]

It appears from my Autodata disc that there is a resistor located between the 2 fans that gives the low speed. This is the speed that should run constantly when aircon is switched on. Full speed bypasses this resistor, and is used for additional engine cooling at 105 degrees. I suspect you have a problem with either the resistor, wiring to resistor or fuse supplying resistor.

Gives you a place to start anyway...

 

[television]

This question has come up before.
On my 99 129 the two electic fans did not come on immediately only when hot. Do bare in mind that the air con /climate is only working when the temperture is set to below the ambiant temperture and no cooling takes place above this.

We have had many car where the electric fan does not come on immediately on the 202 cars.

Malcolm

 

[fouskos]

I think that the problem is solved.

I cleaned both the air con pres. sensor and the electric socket of the aux fans.

And now the aux fans are cutting in at 85C and they stop if temp is below 85C
My conclusion is that the air con pres. sensor was the problem because the aux fans were cutting only at 105C.

What is your oppinion