AC Compressor click click click

[Sdude2008]

Normally with my truck, 2003 3.0 auto, I can hear the compressor cycle on every few minutes. When this happens there is no change in the idle. Recently I had a crack in my radiator and some coolant sprayed across the engine. I cleaned up the mess as best I could and replaced the radiator. My problem now is the compressor cycles on and off every few seconds and when it does the idle drops to almost stalling. This happens while using any of the climate settings, AC and heat. When the inside climate control is set to off there is no clicking and no idle change. Also once I start driving I don't notice any surging only when stopped. I have read here about the idle control valve and I have cleaned it but found nothing changed. Before I go buy a new valve I figured I'd throw my issue out here and see what you all think. Any suggestions are appreciated. Thanks.

 

[daniel3507]

Low refrigerant level? Have heard that can cause the compressor to cycle on and off like that.

 

[Sdude2008]

Just had it checked for leaks and filled about a month ago. I thought maybe something got wet when the radiator blew but I just don't know what to check.

 

[Rearanger]

Just had it checked for leaks and filled about a month ago.

That's not now, that's then. Normal cycling is produced by a properly operating temp switch in the evaporator, abnormal cycling is caused by low pressure switch, high pressure switch or faulty clutch/bad connection. The idle up is controlled by the computer receiving a signal when the A/C is on or from a separate idle-up valve.

You might inspect the A/C belt to see if it's slipping from anti-freeze being sprayed on it. Might just need to adjust or replace the belt.

Are you getting cold air if you keep idle up with gas pedal? If you don't have A/C experience (or gauges) to troubleshoot this then you'd best take it to a shop.

 

[Sdude2008]

Yes getting cold air at all times. I will check the belt and take it in to get checked. Why does the compressor cycle when I switch on the heat? Could the switches have gotten fouled from the coolant shower? Thanks.

 

[4.0B2]

I'd check the freon level...

do you have your defrost on? defrost will make some AC units come on.

 

[Rearanger]

Yes getting cold air at all times.

Sounds like refrigerant level OK. Look for other cause.

Why does the compressor cycle when I switch on the heat?

You'd have to refer to your owners manual as to which switch position also gives A/C depending on temp setting. The "A/C" position is not the only position to give A/C, such as the "Defrost" position.

I'd check the belt first. The compressor may have an RPM counter; when the belt slips that could cycle the A/C.

 

[glackey88]

Low refrigerant level? Have heard that can cause the compressor to cycle on and off like that.

check your binary switch might be going bad but not yet

 

[Sdude2008]

refrigerant ok, belt ok. Binary switch? Where's that?

 

[Rearanger]

Binary switch? Where's that?

I think he means the combination high/low pressure switch. It is possible the switch is bad. You can jump the contacts to see if the clicking on/off stops, but I'd test the refrigerant pressures first to make sure it is not a pressure problem.