Toyota Corolla over heating when the AC is turned on!

I have a Corolla ee90 12 Valve car. Sometimes (not always) regardless
of weather condition (hot or cold) my car's tepm gauge climbs to 3/4th
level and remain static for a while (although significantly below the
redzone) when I turn on the AC. However, the car doesnt seem to loose
power or doesnt effect cooling at all. Still it should not cross the
half way mark on the temp gauge. I have checked without the thermostat,
cleaned the radiator, refilled coolent, changed the radiator cap and
both the fans are in goodworking condition except they turn at half
speed when I turn on the AC and go into full blust when the temp gauge
pass the half mark. I guess the fans relay is programmed that way.
However, without AC temp gauge never goes beyond half mark no matter
how hot the day is. Can anybody come up with any suggestion of my
observation? Pls comment.

 

Not sure why you are posting to a Chrysler group, but...

Due to the way Japanese car radiators are constructed (very narrow
tubes, very fine spacing of external fins), this is classic behavior of
a Japanese car when the radiator becomes marginal (due to partial
internal tube clogging or external fin corrosion and/or clogging with
dirt/bugs). The radiator capacity is reduced so it does fine under
normal load, but turning on the a.c. puts an additional load on it that
pushes it beyond its degraded limit to provide cooling. Do not attempt
to have it rodded or otherwise unclogged - often disasterous and it will
never be back up to anywhere near original capacity.

Replace with a new radiator - they're cheap these days and stocked in
warehouses always within 1 day shipping by ground. I promise you that
is the fix.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Take it to your nearest Dodge/Chrysler/Jeep dealer and have
it replaced with something more stylish and more reliable.

Thanks,
Scott

 

LOL
Lushy

 

Bill,

Thanks for the suggestion. Thats the only thing left to do. But it
still confuse me because its not a regular event when I turn on the AC.
My radiator fins are fine no debris or bugs. Air passed through nicely.
There may be internal clogging. However, i am thinking on another thing
that when I turn on the AC both the fans (condenser & Rad) circles at
half speed, its blows at full power when the temp gauge hit half way
mark then fall back to half speed as the enginess temp comes down less
than half.
Could this be a reason for higher temp?

aims

 

Not sure. It may be operating correctly, i.e., a.c. forces fans on at
half speed, and they go to full when the temperature sensors order it.
But I don't knoe that for sure. I'm still thinking radiator.

May I politely suggest you post to a Toyota forum? I just happen to
know something of classic Japanese radiator problems having owned,
driven, and maintained a Subaru with turbo for 275k miles.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')