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camry 1991 overheat when a/c on

2055 Views 12 Replies 8 Participants Last post by  txturbo
ok i am continueing from the other thread i was a little long :(

anyway i changed the thermostat..

after testing the car for a while now...

i found the car doesnt overheat when the a/c is off thorugh out the trip.

however when i come back home i hear a wheezing sound from the engine and yesterday i could feel bubbling in the pipes and radiator, but not in the overflow tank. the pipe at the top of the radiator was extremely hot and hard however the one at the bottom was not as hot but just as hard. the radiator cap was extremely hot.

when the a/c is off the car doesnt overheat, when i turn it on i notice the indicator slowing increasing, as soon as i turn the a.c off the indicator drops to half again.

the fan is certainly running i could hear it and when i got home i saw it running.

i havent driven the car for a very long drive mostly around 30 odd km at a time.

what would be causeing the boiling and noise in the radiator and pipes?

why does the a/c overheat the car?
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The a/c puts a little strain on your engine, any engine, to keep you cool inside.... a few weeks ago, my brothers 88 4runner's radiator blew, cause i ran the a/c in 103 degree weather, hauling 2000lbs in a trailer for about 20 minutes.
damn thats gotta sux :(

but it wasnt that hot was a cold day...and the a/c was on for one 10minutes :p the first time the second time the i drove the car for about 15min go tit nice and warm then when i turned the a/c on 2 minutes later the temp started to rise slowing. so i turned the a.c off stopped at a traffic light and the indicator dropped to half again :(

very weird :p

i tried to take air out of my engine its funny cause the indicator never reaches half when the car is started from cold and sits idle.

it reaches pretty close to half though. the water goes up and down. when it goes up it pops. after 30min the air popping wasnt as sevear but the water did go up then go down . when i put some coolant to top it off the water would go up then down eventally resting.after 40minutes the water was sort of jumping. no air thoug. after an hour i turned the enigne off and all the coolant at the top went quickly to the bottom :p i had to fill the radiator with more coolant. turned the enine on this time the water didnt go up and down as sevearly as before.
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anyone? or is this a really unique problem :p
yes to the first and second thing..

however i found today some water leaking from where i installed the new thermostat...i think the noise i head ws also comming from there...

would this cause problems? should i tighten the nuts more?

the car never gets hot if the a/c isnt on...but lately i started hearing the transfer of coolant to the overflow tank...

i'll tighted the nuts again tommorrow...
Jiggler goes up on the thermostat...Head Gasket?

On my manual it says to put the jiggler up.! ( but most new thermos have no jiggler)


Have a mechanic do a pressure test on the cooling system. When I had the same prob as you..I found that the head gasket was blowing air into the water jacket. I pulled the plugs the see one had evidence of water in the cylinder.
Mine is a 90 4 cylinder.:chug:
Head was warped too much so I put in a JAP INC. Motor. These come w 40k.
Runs like a top (but it is a Toyota Camry):lol:
You said both fans are coming on, are they going on high speed? Try this little experiment, unplug the cooling fan switch and drive the car with the A/C on, see if it still overheats.

How often do you change your coolant and flush your cooling system? If a radiator is not flushed it builds up deposits on the inside. These reduce the cooling efficiency of the radiator. Might be that. If you're using straight water that would also contribute as water is not as good as antifreeze for cooling.

If it runs OK without the AC I'm pretty sure that exonerates the thermostat and even air in the system. Either of those would probably cause overheating without the AC as well.

If both fans are on all the time that the AC is running then it is either reduced cooling efficiency or increased drag by the compressor. You might want to pull the compressor belt and turn the compressor pulley (after engaging the magnetic clutch) to see if it is too hard to turn. Problem is, I"m not sure how to describe "too hard to turn". It should turn smoothly and rather easily (I equate it with about the same pressure that I use in turning over a model airplane engine???)

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Replies are coming to me ..WHY?

Been getting some replies asking me question when...

Anyway hope you got it figured ..

Here is one of my 4 GEN2 Camry's.


Put a Hitch on this one. ORIGINAL BLACK PAINT....
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I gots a solution.

Dont use the ac. Problem Solved.

At low speed the cooling fans are connected to run in series, low speed. But when the A/C system pressure gets too high, they are switched to run in parallel, high speed. That is why it required three relays to run to fans.

The description of the OP points to that the fans may not be switching to high speed so there isn't enough air flow through the condensor and radiator when the car is at a stop or slow traffic. If could be the pressure switch is having problem switching.

if it were the fans, it would only get hot at low speed. If its getting hot at highway speeds with the a/c on, then you probably have a clogged radiator. Try this test. Let the car sit overnight. Go out in the morning, remove the radiator cap and make sure the radiator is full. Put the cap back on, start the car with the a/c on and let it idle until it gets up to normal operating temperature. Turn the car off, disconnect the negative battery cable and then reach down and feel the radiator directly in the center on the fan side. It should be warm or hot. If its still cold, you've found the problem. Get a new radiator, they are only about $100.
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