tcruz0004

I'm currently troubleshooting my AC system. From the threads I've read I haven't heard of a similar issue yet.

My AC always worked great until this summer. About 3 months ago I started to notice a noise coming from under the hood. I could only hear it when the AC was operating. (Not the fan, only when the AC was engaged.) So after a while I decided to look into it and try to fix before it went out. I figured out that the noise was coming from the AC drive on the accessory belt. It would spin freely and then about every 10 seconds it would stop and make a slight screeching/humming noise.

The AC still worked fine and the noise never got any worse. However, the AC recently stopped producing cold air. Even when the outside temp is in the mid 70's and driving at 35 mph with it set to 60 degrees.

My questions are: do I need to service the coolant? Is this something I should do by myself and if so what is the best stuff to get? Also, what should I do about the noise coming from what I believe is the AC compressor. Is the compressor generally a lifetime part or does it need to be replaced after 10 years or so?

Tommy J

By Ac drive do you mean the clutch would spin freely and then stop. Is it still cycling when the ac is on? The outside pulley always spins but the inner clutch spins/cycles on and off during ac function. It sounds like your clutch may be the culprit and if so there is a possibility that it could freeze up or stop the outer pulley which would in turn produce a wonderful sound of your serpentine belt screaming around the stuck outer pulley. No part is lifetime although some do last. I wouldn't just add product without knowing whats going on. The clutch might not be engaging because of a leak in the system in which case you have a separate issue or the ac clutch is bad and not engaging and your fluid level is fine. The sound you've been hearing could have been the clutch going but not definite. Some amount of small noise may be ok but if you heard it from inside the truck then that's pretty loud. So, you need to find out if you have a leak somewhere. You could carefully take the cap off of the low pressure line and press the valve with a rag around it with eye protection and see if there is anything coming out or left in the system which still may not tell you the full story, you could just be low on product. If its the clutch and you go adding stuff you could mess it up also. I'm by no means an expert so maybe someone could chime in. You might want to take it to your trusted mechanic

nrivera04

Im not much for AC troubleshooting but it sounds like either your AC clutch is going out or your compressor is locking up. Either way, both of those issues will require your compressor to be replaced along with some other parts. AGAIN - I'm no AC expert, so maybe someone else can chime in with a better suggestion.

I can tell you, there's no need to "service" or replace your refrigerant. At best, have somebody with a set of AC gauges to ensure your system is full and just add freon as needed. There is the chance also that your issue is just stemming from low froen, so first and foremost is to make sure your system is fully charged.

redfishtd

You tube it , But if you can't work it out get a good ac repairman on it . Ac systems are expensive and not for novices .

tcruz0004

You guys are on it! I read on some other forums involving AC diagnostics and troubleshooting and the clutch may engage and disengage if the level of refrigerant is too low. Then once the system is depleted it will no longer engage until serviced properly. So the key is to refill the system before it is completely empty.

I purchased some Arctic Freeze today from Oreilly's. Before I add more refrigerant I am going to use a manifold pressure tester to see where the current level is at. (Its better than the regular gauge on the can line, and most stores have them to borrow for free.)

I'll let you guys know the results tomorrow or over the weekend and anything else I learn that will help. Thanks again for the input.

tcruz0004

Problem solved (mostly)

The A/C system was low on refrigerant. You can pick up a bottle from any auto parts store. I also rented the manifold pressure test from AutoZone for free. I found it difficult to get a proper reading. From what I have read, the low side should read approx 40 +/- 10 and the high side approx 250 +/- 20. I did get readings close to this, but for some reason I couldn't get it re-charged all the way. It would always fall a little bit short. Anyway, the A/C blows cold now and I only hear the compressor kick off for about 2 seconds a couple times after start up and when I am accelerating (which I have also read was normal.)

Hope this help.

tcruz0004

A/C system is acting up again.

Loud screeching noise about every 5-10 seconds when the A/C is engaged. Air is cold, but doesn't feel like 60 when set to 60. Going to do some more digging and see if I find anything out. Will report back with any useful information.

In the meantime, if anyone has experience with the A/C compressor or clutch troubleshooting or replacement, please chime in.

redfishtd

Car systems are not completely sealed like a house unit or refrigerator .They have a rotating seal on ac compressor so some small amount over a year so is okay . Ac is subject to a lot of heat and vibration . It also can freeze up and damage coil due to expansion don't run fan on low for long periods .
Clutches can go bad ,compressor can seize and break belt . If gas escapes moisture gets in and makes real bad stuff .Don't let it go too long not sealed up .
You can learn to fix it but you need a lot of study and gauges and vacuum pump . Mostly you have to fix it, then add a new dryer/new orifice ,then
pull a vacuum to boil water out of system and check for leaks .The evaporator coil in dash is a bear to change .
Not a real easy job ,the normal fix at a shop in that case is around 1k .
Only buy real good parts ,normal auto stores stuff is poor . The last condenser coil I did I had to order 4 to get a good one.The better ones come with nitrogen gas sealed in them .;My 05 has 201k and is still going good I added gas twice .
If she seizes and throws belt you can bypass by getting belt for one without ac ,I did have to replace small compressor relay on fender fuse box .
It can also be your blend doors and motors on them causing air flow problems .You can youtube that .

redfishtd

You should know the high and low pressure switches go to the PCM ,the pcm then decides to send a signal to the compressor relay or not .It looks at the cooling temp switches and all that .
Pcm looks at a lot of stuff to be normal like engine temp /coolant temp /limp mode etc .Thats not usually a problem on a normally maintained vehicle . .

tcruz0004

So two years later and the problem is still persistent.

I have added two videos to show what is going on. When the compressor kicks on (off..?) the pressure on the low side drops and the pressure on the high side increases. There is also a noticeable screech.

If anyone knows what is happening or could add some information, that would be awesome.

I'm going to continue to do research and will follow up with the fix (hopefully.)