A/C causes overheating while idling

[Yoni_d]

Hi guys,

In order to check if the engine temperature indicator is faulty or not, I have mounted an external digital temperature gauge near the sensor in order to get the real engine temp.
The results looked good:
running temp (also idling temp) between 83C-87C
However, when I turn on the A/C the engine temp climbs up to ~95C and looks like it will go further more.
This happens when the car is on idle. When it running, the temp is around 87C.
What do you think might be the problem? The thermostat is new and the radiator is also ok since if it was faulty then it would overheat while driving...
The electric fan kicks in on time and works constantly when the A/C is on.
In addition the water pump was also replaced about 1.5 years ago :-\

Important to mention that the A/C air bleed valve is not original so perhaps it allows to much air to go into the engine so the fuel mixture is getting too low?

Any ideas?

[harborman]

I wonder how your belt driven fan is working. How is the clutch in that fan?

[Mrmerlin]

I think you need a new fan clutch/ The A/C fan is supplemental,
the belt driven fan is the main cooling device

[Yoni_d]

I went to a radiator place and the guy there looked at the fan clutch and said that its ok...However, I know its a very difficult thing to check so maybe I will rebuild the fan clutch just in case.
Do you think that rebuilding it (adding the silicon oil) might solve this problem? or should I get a new fan?

[Crumpler]

I'm clearly biased as you can see by other thread...
I initially wanted very much to keep original parts in my car, but the clutch fan was just too much hassle.
Consider going electric Yoni_d, once you get past the guilt of hacking out the belt driven fan your life will be easier. Dave.

[Mrmerlin]

the thing with the belt fan is the brass push rod in the center under the Bimetallic spring.
This little piece of brass gets gouges on its flanks then the oil will leak out ,
it seals to the green cover ,
the rod gets pushed into and out of the fan center,
dont drop it you may lose it
NOTE I have polished this little part in the past if the gouges are not deep,
then it works as designed

[Yoni_d]

Originally Posted by Mrmerlin

the thing with the belt fan is the brass push rod in the center under the Bimetallic spring.
This little piece of brass gets gouges on its flanks then the oil will leak out ,
it seals to the green cover ,
the rod gets pushed into and out of the fan center,
dont drop it you may lose it
NOTE I have polished this little part in the past if the gouges are not deep,
then it works as designed

If I wont be able to repair this clutch then I will probably go electric all the way...I have a question regarding this little pin:
I read somewhere that if I slightly shorten this pin (by 0.5 mm) it might improve the clutch operation. Is it true?
In addition, can I use any silicon oil (as can be found in hobby shops) in order to refill the clutch as long as it 3000 CST? or it must be a certain type of silicon oil such as the silicon oil of Toyota - 08816-03001?

Thanks!

[Mrmerlin]

I dont know the answer about shortening the pin,
I used the thickest silicone oil I could find at the Hobby store they use it for RC cars in the shocks.

IIRC you may not be able to get the Toyota oil anymore and its really expensive ,
and you would buy 2 bottles.
The RC silicone oil does work

[Yoni_d]

Thanks!