I have a 2005 stx 4x4 with a 4.6, when my truck is cold and I start it my ac works fine for about 15 minutes then gets hot, it does this everyday, I don’t think my lines are leaking cuz it’s cold everyday just not very long, my clutch and everything seems to be working fine, any suggestions or things to check out, the drain plug out of the firewall is also clean, Thanks!!

 

The first thing to check would be the low and high pressures if you have verified the compressor is working. Is the compressor cycling at idle speeds or running constantly?

It kinda sounds like the heater may be on at the same time as the AC? Takes a few minutes for the engine coolant to warm up and warms the air?

 

Does it get hot as in air from the heater, or does it just go up to outside temperature?

 

It doesn’t get hot like the heaters on just as hot as outside air

 

I should also add that It doesn’t drip out of the tube, but it also isn’t on my floorboard or anywhere like nothing’s wet

 

If it's humid out, it should be dripping. Maybe the evaporator core is partially blocked? Is the blend door sticking?

You do need a set of gauges and technical ability to see what's going on. Roadie asked if the compressor is cycling?

 

You need to check the compressor clutch operation while the system is not working.

Typical symptoms of excessive clutch gap.

 

It appears like my compressor is cycling fine, we have had gauges on it and everything seemed ok as far as we could tell, I figured out today that if my ac is off and I drive for a while and get my truck up to temp if I turn my ac on it will work for about 15 minutes even when the trucks warm, it doesn’t matter when I turn it on it will work for 15 then go ambient, now I sill say I’m no expert at all with ac systems that’s why I’m here, thanks guys

 

Projectsh089 how would I go about doing that, I’m no auto mechanic but I can work my way around a vehicle if I have guidance or a little help

 

What you have to do is, WHEN IT STOPS or IS NOT WORKING, go look at the compressor clutch. You HAVE to properly identify the behavior to avoid guessing.