Nissan 200SX Air Conditioner is Not Cold at Stops or Idle

Reader Question Hello Austin — Just read your article about A/C troubleshooting ( Air conditioner not cold). It was well written and even brought flashbacks of my undergraduate thermodynamics classes (mech engr).

The reader’s symptom’s were identical to the situation that I’m in and based on your recommendation, I plan to verify that my fans are working. Last year, I had my mechanic refill my refrigerant in my 1996 Nissan 200SX after my DIY attempt leaked most of it into the atmosphere. It helped improved things from where they were (always blowing hot air) to where I’m at now (hot at idle only).

The only difference that I’m encountering from your other reader is that I can get the air to cool down at idle if I rev the engine up to 3krpm. It’s not as cool as cruising speeds (probably due to improved heat exchange from airflow) but it’s notably better than at idle.

Does this suggest a fan problem or something worse?

Thanks for your help.

cheers,

Mick

Hi there Mick, how are you?

I would say you are probably LOW on Freon OR the electric cooling fans are not working. Reving the engine does two things, the belts turn the a/c compressor faster, and the radiator fan pulls air across the condenser, which is what the condenser fan should be doing.

A system that is low on Freon, will cool ok at high rpm, but not very well at low speeds or stops. Check the fans, if they work….check the Freon level, you might be just a can or so low. Of course, if you are low on Freon, you probably have a leak in the system somewhere which you might have to repair if the leak is substantial.

Blessings,

Austin C. Davis