gtg749m

Tried turning on AC today and I keep hearing a 'clunk' noise from the engine bay and no cold air is coming out. The noise will 'clunk'...pause.....'clunk'....pause...until I turn off the AC.

Im assuming this is the compressor which is now bad?

If it is my compressor, do I need to change out the Expansion valve as well or is there a way to diagnose to see if the valve is bad?

Thanks

mister x

A/C repairs are not a DIY unless you have the right equipment. Depending on what failed in your compressor (hopefully it's just a clutch from your description) you could be facing a complete evacuation, flush then recharge. If the refrigeration does need to be replaced, the A/C tech may recommend changing the expansion valve at the same time while your system is dry. Bottom line; have a pro do it.

gtg749m

Oh my intent is to definitely have a professional do it. But I want to go in sort of knowing what is going on with my AC and try not to get ripped off if they try to tack on other stuff.

operator207

Could be the AC compressor cycling. They do that when they are low on freon.
Could you start the car, pop the hood, turn on the AC and look at the compressor to see where the clunk is coming from? if the front of the compressor (clutch for the compressor) is engaging and disengaging and that is where the noise is coming from, simply adding freon (band aide fix only) fixes the sound, you know what the problem is.
If thats the case you need to find the leak, or you will just be pouring money into the AC on the car every summer.
AC Clutches rarely go bad without abuse, and seals, unless disturbed rarely go bad either. At least in my experience.

Of course all he above assumes the clunk your hearing is the clutch simply engaging and disengaging.

AC compressor is all the way on the bottom on the drivers side of the front of he engine.