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2001 metro radiator fan issue; radiator motor works but wont come on
Topic Started: Mar 31 2015, 03:54 PM (1,338 Views)
cantgetright
New Member
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I recently was handed down a 2001 chevy metro. It would die when you gave it gas until warm than ran ok. I replaced the engine coolant temperature sensor and it started and ran great. As it warmed up the fan never kicked on. I replaced the thermostat as well. The car very slowly began to overheat and the gauge went into the red. The fan wouldn't engage and the radiator upper hose didn't get hot. I put the old thermostat back in after testing it and the upper hose got warm as it should. The fan still did not engage and the car slowly over heated. I checked the fan by jumping it to the battery and it ran. I checked the relay with my multi meter and it seemed to check out. I also jumped the relay and could hear it switch. I really do not want to wire the fan to a switch. Any help or ideas would be greatly appreciated.
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idmetro
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Welcome aboard! As I recall, there are two temp sensors - one feeds the signal to the gauge in the dash (appears to be working), the other controls the fan. Not sure if a 2001 is the same as earlier models but on the earlier ones the fan is controlled by a sensor that has a two prong connector if you unplug the connector you can test the fan by jumpering across the plugs. Someone with more knowledge of the 2001 should be along shortly to clarify.
Edited by idmetro, Mar 31 2015, 04:06 PM.
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cantgetright
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I know the Haynes manual mentions the bridge procedure and the sensor. I do not believe it is on the 2001. It says it will be in the thermostat housing. Only the engine coolant temp sensor is there. Sadly the manual covers all metro models and doesn't clarify if this sensor is on the 2001. I'm sure something must act as a sensor for it, just not sure what or where.
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Metromightymouse
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Powdercoat Wizard

Yeah, the only usable manual for this car is a factory service manual. You should get one at your earliest convenience and find a creative use for the Haynes. In the meantime, there should be a sensor that runs the fan, try tracing the wires to see if you can locate it.
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Woodie
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I think the fan is controlled by the PCM on the newer cars. You say you have identified the fan relay. If so, trace the trigger wire on the relay and see if it goes straight to the PCM.

Sounds as if you don't have enough water (coolant) in it.


Edited by Woodie, Apr 1 2015, 09:32 AM.
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Hanuman
"The Almighty Grounds Cleaner"

Woodie
Apr 1 2015, 09:30 AM
I think the fan is controlled by the PCM on the newer cars. You say you have identified the fan relay. If so, trace the trigger wire on the relay and see if it goes straight to the PCM.

Sounds as if you don't have enough water (coolant) in it.


bingo! :gp
BURP THE COOLING SYSTEM.......(caps lock)

park it on a up hill slope.
remove radiator cap.....
run engine untill warm.....any air shoud get burped out of the system.....refill.


your fan....you mentioned checking everything except......the fuses.
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cantgetright
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I did check the fuses but did omit that. I have bled the system but have not tried the parking on a hill/Jack stands yet. I will try that this weekend. I checked the fuses with multimeter and not just visually. Today I also took down all grounds in the engine bay and gave them a good cleaning.
Edited by cantgetright, Apr 2 2015, 12:36 PM.
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freegeo
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The fan is controlled by the PCM. If you unplug the coolant temp sensor (which is on the thermostat housing) the fan should come on. Try that and see what it does. Make sure your hand aren't near the fan when you unplug it though.

Here is a diagram for a 97. Yours should be very similiar.

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Silver2K


Until you figure out what the problem is with your radiator fan, in a pinch, when you come to a stop, turn on your cabin fan set to max heat. It will keep the car from overheating. When you get going, turn off the cabin fan.
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cantgetright
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Freegeo, I removed the engine coolant temp sensor plug and the fan came right on. So what does this mean for my pcm? I will do the burp attempt mentioned, in the morning for the radiator.
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myredvert
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myredvert

Like MMM said, find a creative, non-automotive use for the Haynes and get a real Factory Service manual for your year. :thumb

Then, you can run the real diagnostic procedure in section 8A-37, Electrical Diagnosis, Coolantg Fans. There will be a functional check chart, which specify the appropriate diagnostic procedure for the condition. For example, in the earlier year FSMs, Chart #2 is Radiator Fan Motor Does Not Run. There will be a similar diagnostic procedure for the newer years.

As Woodie said, in the newer models the PCM controls the coolant fan. You can randomly/blindly check individual components, but the actual diagnostic procedure will check each component in the proper order and if followed properly will also identify potential wiring issues in between components.
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