A/C going belly up? You be the judge...

[DieselFiend]

This is a new problem with the truck. Maybe some of you have experienced this before. When I first start the truck and kick on the A/C in the fresh air mode, the compressor makes a really loud noise. Kinda sounds like a "thwap" and it sounds like it's relieving pressure built up or something. When in idle or high idle it clicks on then off really quickly and sounds like its placing an enormous load on the engine. I also don't feel cool air coming from the vents. Here's where it gets kind of wierd. As soon as I start driving, it starts blowing cool air and cycles normally even when I stop the truck and it's idling again. I've had the truck for three years and haven't serviced the A/C yet. It's got 83K on it right now. Any ideas? Is my compressor going bad?

 

[SierraRam]

No the 134a refrigerant systems always seem to make a clunk when intially starting. I would have someone check the charge you may be running a little short,

 

[DieselFiend]

I'll have someone check the charge. It's used to thunk. This new sound is quite a bit more pronounced. It's like a hiss then a thwap.

 

[MMeier]

Check the charge, small chance your fan clutch may be headed to the dumper also. Both times when mine went the air would cycle off and one quite a bit, then once i was moving it would seem to stay engaged a bit longer due to air flowing over the coolers and lowering the head pressure in the compressor.

 

[DieselFiend]

Hmmm, yeah, I think my fan clutch is taking a crap. Is that covered under the engine warranty?

 

[Skydiver]

First, clean the bugs from the front coil. I would reccomend compressed air. They will look clean even when they are clogged up. As a test you could mist some water in the front area (not while driving) to see if it starts cooling.

You say it starts cooling when you start moving tells me there is no air flow. Could be a weak fan clutch.



My air cond. instructor in school taught me "you do not cool anything. You remove the heat".

 

[DieselFiend]

I'm 99. 9% sure it's not a clogged front coil. I think it's a combination of a weak fan clutch and low charge. I'm not setting any DTC's for the fan clutch yet so I'll get it charged and see if that helps.

 

[GShail]

I guarentee you have fan clutch failure.

 

[sag2]

Fan Clutch

 

[GShail]

Fan clutch will not always set codes. After you figure out that it is indeed the fan clutch, try replacing said fan clutch and then put in some additional Rapid Cool Thinline fans to assist your cooling. This has worked well for me and I got the idea from sag2. Thanks again sag2, my fan clutch woes are behind me!