Question about 2000 Toyota Sienna

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Overheating with AirCon ON, OK with Aircon OFF

I have a Toyota 2000 Sienna with overheating problem. The overheating only happens when the Aircondition is switched ON. The thermostat has been removed and the two fans wired directly to always be on. The radiator is not leaking and is still very good. We have replaced the fan with a high speed fan but problem remains. I travelled over 500km without Aircon and the temperature gauge is at about a quarter. Please help out

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If engine over heating coolant over flow jug will boil over you will see steam.sound like you have either faulty engine coolant temperature sensor or could have faulty fans relay or fuse or pcm problem if coolant fans dont turn on.have garage with code scanner that can do a snap shot on coolant temperature sensor check see how hot coolant temperature is see if coolant temperature over 220 degrees engine getting too hot.could have faulty water or blowed head gasket check engine oil on oil dip stick look milkly you have blowed head gasket. i use infra red laser thermometor check see how hot engine is over 107 celsius engine is overheating.

Posted on Dec 10, 2012

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Posted on Jan 02, 2017

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SOURCE: radiator & aircon fans not switching on in a 1994 camry

Start car. Turn on a/c. check for power to the fans with meter. Remember, this is d.c.power. If power is there, fans are bad. Replace. Be sure they have a good, solid ground. If no power, look further up the circuit for where you are loosing the power.

Good Luck

Posted on Feb 21, 2009

  • 330 Answers

SOURCE: overheating

1. start the engine and leave the radiator cap open.
2. put a cardboard cover or a rug in the front of you radiator.
3. let it runs 20 minutes or more, see if it is overheated and see the water or coolant in the radiator circulated or not. If not, as soon as you have already changed water pump. thermostate and check the hoses, no leak, I think your radiator was blocked.

Did you put stop leak before?

Posted on Jul 07, 2008

SOURCE: overheating, after 4 or5 miles engine gage is in

Please solve this problem, my car COROLLA 1988 automatic 1.6 has the same problem!!!!!

Posted on Nov 20, 2010

  • 1 Answer

SOURCE: My 1996 toyota avalon is

Is the fan coming on? If not, possible lower radiator fan switch/sensor? No leaks... So overflow tanks level stays stable? How do you know it is overheating? Elevated temp guage? Engine smells overheated? Both? We need more info.

Posted on Dec 25, 2010

  • 1 Answer

SOURCE: overheating toyota tacoma

i have a overheating problem,i changed the thermostatand driving from sea level up to 4000 feet it over heats ,what is wrong

Posted on Jul 10, 2011

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2000 2.7 toyota prado overheating issues coolant looks fine oils clean seems to happen when aircon is on will flucuate up n down between half and hot

Could be a blocked radiator internal or external, or a faulty viscous fan hub..

Check fan hub has resistance to turn..

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are you referring to the engine temperature overheating or the cabin temp not cooling down with the aircon on? I am struggling to think of a reason why operating the aircon would affect engine temperature

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My car said "engine hot

Full coolant level does not mean your engine cannot overheat. You need to fix the problem as overheating will destroy the engine if not addressed.

The radiator cooling fans must be working, as must the water pump. The thermostat must also be working properly.
There must also be no air in the cooling system as air locks will impair water flow. When cooling systems are drained fully or partially and re-filled air in the system must be bled out using the correct bleeding procedure for the particular engine/cooling system. Failure to do this properly will lead to overheating.

If you ONLY see the overheating warning when running your aircon you need to check that the electric radaitor fans are kicking in at idle when you switch on and run the aircon and the engine has been warmed up some. If they do not start operating when the a/c is running you will get an overheating condition in normal driving conditions.

If the radiator fans are operating normally and you still get an overheating warning when the aircon is on or off the most likely culprit is a faulty thermostat in the engine's cooling system which will need to be replaced.

If you have either a faulty thermostat or if the water pump in the cooling system fails you will get continuous overheating whether the aircon is on or off.

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1. check if your water pump is is working.
2. check if it is not overheating when the A/C is off. if it is no longer overheating, have your a/c compressor checked by an aircon technician

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My car overheat when im using the car aircon,it doest overheat when im not using the aircon,so how can i use the aircon with out overheating my engine,i already clean the radiator,condenser,check the...

The cooling fan should run continuously when the A/C is on. If it does then I suggest you drain and flush the cooling system, and replace the thermostat. Fill it with a fresh supply of a 50/50 mix of antifreeze and distilled water.

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Apr 20, 2010 | 2007 Toyota Camry

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It really does overheat a lot when in traffic.

You need to check youe water pump, thermostat and your radiator cap and if all of that is good it sounds like a blown headgasket.

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I have a toyota corolla xl 96 model. My problem is that whenever we will use the aircon the engine light will blink and you will see some engine oil spills but if we will not use the aircon the car is...

Are you sure you are seeing engine oil or is it coolant??
Chances are that it is coolant and that when you use the AC the engine is overheating. Do you have a temperature gauge on that car to indicate the engine temperature??.
Make sure your radiator fans are working--when you turn the AC on the fan at the back of the radiator should come on.

Nov 24, 2009 | 1996 Toyota Corolla

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Idling high

There may dirt or rust in idle air passes
Service & adjust the Idle speed control valve & throttle position sensor.

Oct 21, 2008 | 1996 Toyota Corolla

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