Where is the controller for the cooling fan on W210?
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Newbie
Joined: Feb 2012
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2000 E320
Where is the controller for the cooling fan on W210?
The car is a 2000 E320.
Friend of mine own it and asked me to help with repairs. It has nearly 90K miles and still had the factory installed thermostat. So when he said it was running warmer than normal I suggested we change the thermostat and expansion tank cap to just do a minor tune up on the cooling system. I replaced things with all OEM parts and refilled the system with the G05 Zerex coolant.
With the air temperature around 70 degrees the car runs just over 80 C while in motion. Extended idling and it goes slightly higher but it is notable. So I called him up and asked how it ran before the issues and he says it was always well under 80 even in 100+ degree summer weather.
I asked him about the cooling fan and NOW he tells me in the past he used to hear it run super fast at times. As is....it runs very slowly and if you turn on the a/c it speeds up but is no where near the speed of electric fans in other cars I have worked on in the past. You can not even hear it running as things are now.
I suspect the module that controls it is faulty or a sensor that tell the module how hot the coolant is may be the problem.
Where is the module and is there any kind of diagnostic test I can run on the fan system?
In many Japanese cars there is a resistor in the power supply circuit that goes bad and results in a slow or dead fan. Is there is resistor in W210 that fails?
Thanks
Friend of mine own it and asked me to help with repairs. It has nearly 90K miles and still had the factory installed thermostat. So when he said it was running warmer than normal I suggested we change the thermostat and expansion tank cap to just do a minor tune up on the cooling system. I replaced things with all OEM parts and refilled the system with the G05 Zerex coolant.
With the air temperature around 70 degrees the car runs just over 80 C while in motion. Extended idling and it goes slightly higher but it is notable. So I called him up and asked how it ran before the issues and he says it was always well under 80 even in 100+ degree summer weather.
I asked him about the cooling fan and NOW he tells me in the past he used to hear it run super fast at times. As is....it runs very slowly and if you turn on the a/c it speeds up but is no where near the speed of electric fans in other cars I have worked on in the past. You can not even hear it running as things are now.
I suspect the module that controls it is faulty or a sensor that tell the module how hot the coolant is may be the problem.
Where is the module and is there any kind of diagnostic test I can run on the fan system?
In many Japanese cars there is a resistor in the power supply circuit that goes bad and results in a slow or dead fan. Is there is resistor in W210 that fails?
Thanks
MBWorld Fanatic!
Joined: Nov 2004
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W221 S600, W220 S55 AMG Kompressor, W124 300E, W140 S320, W210 E3204M W164 ML320 Bluetec
It does sound like it is running at the proper temperature. If it runs and stays cooler than that the fuel economy will likely suffer. A touch over 80°C should be normal. If it was running cooler than this it probably indicates there was an issue before with the thermostat opening too much.
Newbie
Joined: Jun 2012
Posts: 2
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1999 E320
Engine Cooling Fan Running Slowly?
Hi All,
I just got a 1999 E320 and am learning about this car. 1999 E320s have an electric radiator cooling fan behind the radiator. No clutch drive fans on these cars. No aux fans in front of the radiator on this car.
I noticed the following about the engine temperature:
- While moving in town or on the highway, AC off: ~85-87 degC exactly.
- Idling / stuck in traffic, AC off: ~95-97 degC. Cooling fan runs, but the fan speed seems very slow - like 2 revs per second. If I turn on the AC, fan runs higher, but I wouldn't say that it's fast; engine temp stays at 95deg C. Ambeint temps are around 70F - very mild.
I don't particularly like it idling at 95-97 deg C on such a mild day (what happens when it gets 110F here stuck in traffic, as it does sometimes....) I found another post on thermostats which shows photos of instruments at highway speed and at idle, all right at 85deg C, consistently. My toyotas only vary over maybe a 3 or 4 degree span, not 10-12 degC span.
I changed the thermostat - identical behavior - no change.
Question: how do I CONFIRM whether the fan is running at the right speed? Many vague posts, but there must be a way to test voltage vs. speed or voltage into a regulator vs. voltage to fan or something?
Any advice would be most welcome - Thanks!
Fred
I just got a 1999 E320 and am learning about this car. 1999 E320s have an electric radiator cooling fan behind the radiator. No clutch drive fans on these cars. No aux fans in front of the radiator on this car.
I noticed the following about the engine temperature:
- While moving in town or on the highway, AC off: ~85-87 degC exactly.
- Idling / stuck in traffic, AC off: ~95-97 degC. Cooling fan runs, but the fan speed seems very slow - like 2 revs per second. If I turn on the AC, fan runs higher, but I wouldn't say that it's fast; engine temp stays at 95deg C. Ambeint temps are around 70F - very mild.
I don't particularly like it idling at 95-97 deg C on such a mild day (what happens when it gets 110F here stuck in traffic, as it does sometimes....) I found another post on thermostats which shows photos of instruments at highway speed and at idle, all right at 85deg C, consistently. My toyotas only vary over maybe a 3 or 4 degree span, not 10-12 degC span.
I changed the thermostat - identical behavior - no change.
Question: how do I CONFIRM whether the fan is running at the right speed? Many vague posts, but there must be a way to test voltage vs. speed or voltage into a regulator vs. voltage to fan or something?
Any advice would be most welcome - Thanks!
Fred
