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A C repair on 2001 Nissan Frontier

My son has a 2001 Nissan Frontier that the AC was not quite as cool as it should have been. We purchased a can of 134a with the gauge on it and followed the instructions on the can. When we finished the air from the vent was at 44 degrees. Today the compressor is cycling on and off every 3 seconds and the air is at 80 degrees. Could we have to much Freon in the system? Would that cause it to cycle on and off or do we have something else going on? Also it was blowing 60 degree air when we started. I would apperciate any help yall can give. Thanks

It’s very difficult to tell what’s going on inside an A/C system without knowing both the high and low side pressures and those cans of refrigerant with a gauge attached will not tell you the whole story.

Yes, it is possible to overcharge a system and the compressor should not be cycling on/off every 3 seconds.
One would like to have about a 50 degree drop, minimum, in the vent outlet air as compared to the ambient temps outside. The pressure and temp should also be checked at elevated RPMs. (preferably around 1500 or so)

The low side pressure is roughly equivalent to the temperature of the evaporator so 60 PSI is not very good at all.

I believe this era of Frontier did have some issues with the thermal amplifier, which is part of the compressor controls. It’s possible the low side pressure is staying elevated because the compressor is not cycling on long enough due to a thermal amp fault. That’s a wild stab at the problem without knowing the details behind pressures and whatnot but hope it helps a bit.

The system could be cycling due to over-charging, tripping the high-side pressure sensor, or cycling due to a low charge, maybe from a leak. You need a set of gauges attached to figure this out. It may be cheaper to have a mechanic to work on it. A good set of gauges can be pricey.

This is why I always recommend people take their AC problems to someone with the proper equipment and expertise. Automotive AC, in my humble opinion, is NOT do-it-yourself.

I know they sell recharge kits in every auto parts store in the land. Doesn’t matter. You need specialized equipment and knowledge to correctly diagnose and repair automotive AC systems. These things are not found in most home garages.

Tell your son to take his truck to someone who knows what they’re doing.

Yesterday we let some of the refrigerant out ant it stopped cycling on and off. The air got down to 44 degrees. That was late in the evening and the outside temp was 86. Today when it was around 97 it did not cycle on and off like before but the discharge air was only 56 which is not perfect but better than 80. thanks for the help. I think we are headed in the right direction.