Mechanics

THE RADIATOR FANS DO NOT WORK HOW CAN I CHECK THE SENORS

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
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JCROSBYMS
October 11, 2011.




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.

Make sure wiring to fans is hooked up. Do fans run with AC on?

Docfixit
Oct 11, 2011.
Air in cooling system is the most common cause of overheating after repairs.

Was the system bleed of air after repairs?

KHLow2008
Oct 11, 2011.
HOW DO I BLEED AIR FROM COOLING SYSTEM

Tiny
JCROSBYMS
Oct 11, 2011.
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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KHLow2008
Oct 11, 2011.

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