paknight12

I've had dye run through the hoses to see any leaks, and freon re-filled twice only to have the AC still blow warm. Someone mentioned replaceing the thermostat and I just wondered if anyone had any other ideas. Its a 93 4 runner with 163,000.

Brian R.

Did you look at the evaporator for leaks? Must be leaking out somewhere. Does it blow warm because it's malfunctioning or because it's low on freon?

paknight12

after its been refilled with freon it works for a week or two then gets warm again. With the dye and black light they have not been able to find any leaks anyplace. Didn't know if the thermostat was a realistic option to replace or not.

Brian R.

Freon doesn't just dissappear. There is a leak and they have to look harder. The evaporator is the obvious spot to look, since it is the least accessible.

I don't see how the thermostat could be at fault. If the freon leaks out (as it appears) then your problem is a freon leak, not a thermostat.

andrew348

do you trust the mechanic . i agree that the thermostat is an unlikley cause . but i have seen overheating cars cause excessive pressure in the ac system due to the fact that the condenser is next to the radiator . this excessive pressure can blow the refrigerant out the high prssure safety port. if u trust thr guy gowith it my gut feeling while reading this thread is leaking evaporator but the dye shouldleave a stain in the drain tube .

ToyotaTech1

I agree I have seen many of these 4 runners leak at the evaporator. If you do replace the evaporator make sure and replace the expansion valve and the pipe that goes to it they are also known to go bad. As for the leaks use a leak detector rather than dye. They will pick up very small leaks easilly.

Brian R.

Yes, for anything beyond a leak at an obvious connection, you will be better off with a leak detector.