What sensor is this......

haroonz7

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guys

Whats the sensor in the photo....ive had a fee cooling issues of late.

The temp gets up to and sometimes over 110C. Ive checked the main fan and its fine, changed the thermo and rad cap. But no joy the temp still climbs to 110C and sometimes over this. At this point i have to put the heaters on and the temp does then drop. I should mention the temp only goes beyond 110C if am stuck in traffic or ive just come off the motorway.

The sensor shown in the pic has 2 connectors and when I remove a connector the 2 smaller fans on the radiator start to run??

Ive never noticed these fans to run before....

Can anyone give me some advice to what this is and what it should be doing?

Thanks
 
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haroonz7

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sorry guys cant seem to upload a photo....but its a sensor with 2 pins sticking out at the top, front of the engine where one of the coolent pipes goes in....i think its a coolent temp sensor?/
 

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Upload the picture to somewhere like photobucket and then link it to there.
 

roadhog

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I've not got my x10 to hand but that does look like a temp sensor.
 
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haroonz7

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if the sensor was faulty would it cause the temp to go over slightly??
 

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Auxiliary Fans

From what you say, it does sound as though that sensor controls the two small fans, since they run when you disconnect the sensor.

If it was mine, I would get the car up to temperature and then disconnect the sensor for a bit to see if the over temperature is controlled to a more normal level when the fans are running. As the car over-heats in a traffic jam, this could be done with the engine running and the car stationary. If this works, I would be replacing the sensor.

Hope this helps, but somebody might suggest another approach.

Ernie
 
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haroonz7

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Bit of an update, had a 100 mile run yesterday and temp went up to 110 soparked up and disconnected the sensor in question. The 2 small fans kicked in after a few min the temp was just above 80 so looks like it could be the cause.

Are there anymore bits of info from anyone else?
 

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This all seems backwards to me,,, yes it looks like a thermal switch in the photo, now these switches complete the circuit and turn the fans on only when connected to this switch sensor. it cannot turn them on while disconnected

No electric fan turns on under 100c

The thermostat on this engine opens at 80c, and the Visco engine fan should come on to full power just after this thermostat opens

I hope to post back
 

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On a 202 with the 605 engine you have a basic cooling circuit, this has nothing to do with any electric fans in the rad.

There are 2 types of thermostats, one opens at 80c and the other at 97c, the water is in full circulation once it is open and the Visco engine fan kicks in.

The electric rad fans are part of the air con system, as before they kick in at 107c and off at 100c in stage one and put 9 volts through the fan. In stage 2 they come on at 115c and off at 107c with 12 volts on the fans

So is the engine too hot if you have the 97c engine thermostat ???? Is the visco fan cutting into full power at this temp
 

roadhog

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On a W124 with the 250D engine that sensor controls the electric fans. I haven't got it on my 300D but the casting has got the space for it.
I agree with Malcolm that usually the sensor makes a switch rather than breaks it but at this stage I'd replace the sensor and see what happens.
 

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On a W124 with the 250D engine that sensor controls the electric fans. I haven't got it on my 300D but the casting has got the space for it.
I agree with Malcolm that usually the sensor makes a switch rather than breaks it but at this stage I'd replace the sensor and see what happens.

This is still nothing to do with the engine cooling,,it just comes on because the coolant circuit is running too hot
 

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:confused:

Is that not the same then?

Not really,,we have one circuit for the cars cooling,,that should keep the engine at the correct temp,,if the car did not have air con,,then it would not have the rad fans fitted.

The rad fans are part of the air con, and if the rad on the car was too hot,,then because the sensors are fitted to the car,,they will come on just because the rad is too hot, it is possible that the main radiator is clogged and the water circulation is poor.

These things must be dealt with as two separate things and dealt with accordingly
 
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haroonz7

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I did read somewhere those fans are for the air con. I'll try a coolent flush first and see what happens with the temp. I did do the 'carrot' test on the main fan and it was fine.

Am not too sure what temp the thermo opens, I got the new one from mb and that's the one they said is correct for this car so I went with it.
 

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I did read somewhere those fans are for the air con. I'll try a coolent flush first and see what happens with the temp. I did do the 'carrot' test on the main fan and it was fine.

Am not too sure what temp the thermo opens, I got the new one from mb and that's the one they said is correct for this car so I went with it.

I think that the rad could do with descaling if possible.

The thermostat could have been the 97c version,,and your old one could have been to 80c
 
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haroonz7

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How does the descaling process work?
 

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How does the descaling process work?

You empty into the rad and they dissolve some of the rubbish..

There is no guarantee that it will work,,but many rads are now suffering as Bolide says, due to the age
 


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