HELP AC ISSUES!

My ac is working ok. But it will blow cold as hell then cut back and blow a little warmer. not hot but just not cold. When I am cruising on smooth highway at 70 i can feel the compressor cut in and out every 30 secs or so. Is this normal? do i need a new compressor? Compressor clutch? Recharge? any help would be great!

 

^^^ Mine does exactly the same thing if it is either slightly overcharged or slightly undercharged. The system likes to be precisely charged by weight according to the label under the hood, otherwise it acts goofy. Look at the label and see how precise they want the charge.

Have you by chance either had the system charged recently or has it been a long time since it has been charged?

If you have "topped up" the system recently I would first look to an overcharge as the problem. However, if it has been a long time since it was charged, I would look for a leak, fix the leak if one is found, and then properly charge the system. Remember the A/C system slowly leaks from the moment it is charged. Constant vibration and aging seals will leak the refrigerant out over time.

The compressor cycle time is based on a whole bunch of things, including ambient temperature, relative humidity, etc. Also there is a pressure switch on the line from the condenser to the evaporator that will cut the compressor if pressure climbs to high, or too low. And there is a thermistor on the evaporator to cut the compressor to keep the evaporator from freezing up. And finally, if you floor it, the compressor cuts out to give you some extra short-term power.

The factory manual does not define a "normal" compressor cycle time. Rather it defines acceptable system pressures relative to ambient temperature.

 

Thanks for the information!