1998 E300 TD radiator fan did not go into high speed
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1998 E300 TD
1998 E300 TD radiator fan did not go into high speed
The E300 TD's radiator temperature has been creeping up. Today, it ran into the red zone with radiator fluid leaking from the cap. It was only ~75F outside with air conditioning running, stop and go traffic. When I checked, the radiator fans were barely turning. I recalled they turned at high speed on a hot day. What connects the fan speed with the radiator fluid temperature? Any idea what gives? Thank you.
Last edited by Hikingmapa; Jul 13, 2012 at 01:23 AM.
Thread Starter
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Joined: Sep 2010
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From: SF Bay Area
1998 E300 TD
This is very strange, there is a resident "I" in another forum who indicates to folks that to solve his diesel overheating problem he removed all the fan blades. Go figure.
One thing for sure is that diesels run cooler than gassers and although you may have a fan clutch problem, I believe there are other things going on within the cooling system to cause your problem, possibly a bad thermostat-----and that is were I would start.
PS: also use the correct fluid, not the pink or green crap!!
One thing for sure is that diesels run cooler than gassers and although you may have a fan clutch problem, I believe there are other things going on within the cooling system to cause your problem, possibly a bad thermostat-----and that is were I would start.
PS: also use the correct fluid, not the pink or green crap!!
THinking out loud, I guess if the thermostat stuck again half way, there may not be enough heat going thru the sensor? to trigger increase in fan speed?
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From: SF Bay Area
1998 E300 TD
Its been a year, and after a blown radiator, I have a new radiator. Temperature is still high ~110C and the aux fans still did not kick into high speed. A shop suggested to check for AC refrigerant leak. They somehow think low in refrigerant will cause overheating. They also checked the resistor network that they said control the fans, and that is ok. I am tempted though to change the temperature sensors because that seems to be the logical thing to do. Plutoe, you mentioned SAM and air control module. What is SAM stands for and where are they located? I did change the air blower motor regulator. Will that be the problem?
Last edited by Hikingmapa; Jul 17, 2013 at 03:53 PM.
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Junior Member
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From: SF Bay Area
1998 E300 TD
My mistake. It runs ~110C city driving (I did go back and edited the post on 7/16.) On freeway, it does maintain temperature ~80C, which is around the temperature it used to run before the problem.
Last edited by Hikingmapa; Jul 17, 2013 at 04:16 PM.
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1997 E300D
If it cools well on the freeway, you may have a problem with the clutch on your mechanical fan. It should not free wheel when the engine is hot. Your electric fan should come on high when the temperature goes up, but I don't know where the sensor is on your car. I would have someone check both the fan clutch and the temperature sensor for the electric fan.
