[[email protected]]

2001 Subaru Forester. Coolant is full in the backup tank.
After driving ~100 miles, temperature indicator is shooting to red area.
When turn off air condition, indicator returns to 75% position.

Any maintenance work needs to be done to the A/C?

Thanks in advance.

 

[Kevin]

Check that both your radiator fans switch on when you turn on the a/c. There could be a faulty connection or a fuse blown somewhere.

Welcome to the forum!

 

[TAGXT04]

Is there any dark fluid or an oily smell to the coolant in the backup tank?

 

[vavrath]

If the radiator stays cool and there's enough coolant in the system it might be a water thermostat that's sticking. The thingie that opens up the coolant circulation when the car gets warmer. Get it changed, quickly. Otherwise bad things can happen. Had this on my previous car, the part is cheap but the effect is huge.

 

[Roo]

Blown head gasket, I'm afraid. Your thermostat probably hasn't ever been changed, and is stuck and/or your water pump is no longer working.

It has nothing to do with the A/C itself.

BTW, location would help us give you more relevant information.

 

[Subaru420]

The two usually problems as everyone mentioned thermostat or fan switch....
First check oil dipstick see if any water have gotten into engine if not proceed by turning on engine until it warms up then when it hit middle in temp gauge check if fan is spinning and check upper raidiator hose to see if it builds up any pressure. If upper raidiator hose is no pressure replace thermostat, and repeat... I'm not a pro here so forgive me if i left anything out.......