The radiator fans do not work

Tiny
JCROSBYMS
  • MEMBER
  • 1999 TOYOTA SIENNA
  • 200,000 MILES
I just replaced the radiator & the van started to overheat after few min. On the hwy as soon as I opened the hood I saw that nethier of th dual fans were working and the resovir bottle was bubbling I checked the fuses for the fans and they are fine
Tuesday, October 11th, 2011 AT 3:25 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If it was overheating on the highway, the fans wouldn't have made a difference. There is another problem. I'm not saying the fans shouldn't have been on, but at highway speeds, the air flow through the radiator is more than the fans can produce. Have you replaced the thermostat? Also, with the engine cold, remove the radiator cap and start the engine. If coolant shoots from the radiator, chances are you have a bad head gasket.
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Tuesday, October 11th, 2011 AT 4:07 PM
Tiny
JCROSBYMS
  • MEMBER
  • 3 POSTS
HOW DO I BLEED AIR FROM COOLING SYSTEM
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Tuesday, October 11th, 2011 AT 6:05 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Top up coolant.
Turn heater to maximum.
Run engine for 5 minutes with radiator cap off.
Add coolant if necessary.
Stop engine.
Add coolant if necessary.
Start engine and if level does not drop, close radiator cap.
Run engine till operating temperature, radiator fan comes on.
Allow to cool and recheck coolant level.
Add coolant if necessary.
Repeat process if coolant level is very low when rechecking.
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Tuesday, October 11th, 2011 AT 6:28 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
It sounds like the fan relay is not working here is a guide and a diagram to help you get the problem fixed.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Please run this test and get back to us so we can continue helping you.

Best, Ken
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Friday, March 17th, 2017 AT 2:19 PM
Tiny
HATILTON
  • MEMBER
  • 4 POSTS
  • 2000 TOYOTA SIENNA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 65,000 MILES
Radiator fan does not come on
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Friday, March 17th, 2017 AT 2:19 PM (Merged)
Tiny
BILLYMAC
  • MECHANIC
  • 2,204 POSTS
Temp switch and fan relay control this. I would replace temp switch [sensor] and then the relay.
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Friday, March 17th, 2017 AT 2:20 PM (Merged)
Tiny
BJO123
  • MEMBER
  • 2 POSTS
  • 2004 TOYOTA SIENNA
  • 3.2L
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 145,000 MILES
This winter I noticed that the heater doesn't work unless I'm driving the car. Sitting at a stop light it gets cold.
Than the radiator fan started running frequently, cycling on and off. One day I was stuck in traffic and it was 88 degrees outside and my radiator fans were on and my temp gage started moving to hot and as that happened my AC got warm.
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Friday, March 17th, 2017 AT 2:20 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Is coolant level full? Maybe a thermostat problem
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Friday, March 17th, 2017 AT 2:20 PM (Merged)
Tiny
BJO123
  • MEMBER
  • 2 POSTS
Yes coolant is full. Freon may be a little low. Could the heater block clogged? Radiator fluid has not been changed in 4 years?
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Friday, March 17th, 2017 AT 2:20 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Yes that is a very good possibility but does not address fans and AC warming up that would have to br due to radiator temp being up causing heat transfere to condenser ie. Warming AC vent temp
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Friday, March 17th, 2017 AT 2:20 PM (Merged)

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