Hey all,

So, I replaced AC components yesterday on my 01 24v which got rid of the compressor squealing from an out of round bearing. Sounded great and was cold as ice. Drove home and now it’s a high pitched (bearing squeal) noise again… Manual warned about a bad fan clutch hurting compressor and I disregarded that (oops). Anyone ever have this happen in such a short amount of time? Or do you think it's maybe another pulley and it's just coincidence a different one went right as everything sounded fine with the new compressor before driving home?

 

More questions than answers.  Is the noise EXACTLY the same as before?  How far is the drive home? 2 miles..., 30 miles?  Did the noise occur right away?  What are the engine rpms when the noise occurs?   Does the noise still occur when the AC compressor is not running?

 

When you had the serpentine belt removed, did you check the condition of the other pulleys?  How about the belt condition?

 

These details are needed to help eliminate possible sources of the noise.

 

- John

 

9 minutes ago, Tractorman said:

More questions than answers.  Is the noise EXACTLY the same as before?  How far is the drive home? 2 miles..., 30 miles?  Did the noise occur right away?  What are the engine rpms when the noise occurs?   Does the noise still occur when the AC compressor is not running?

 

When you had the serpentine belt removed, did you check the condition of the other pulleys?  How about the belt condition?

 

These details are needed to help eliminate possible sources of the noise.

 

- John

 

So for the noise, it's not as loud and obnoxious as the previous compressor was. Previous compressor clutch went out and we removed the assembly and had to head up the pulley to get it back on. Little too much heat caused it to be loud and high pitched. 

 

Put on the new compressor and other new A/C components and the truck sounded great, no high pitched squealing. Drove about 10mi, got food at drive thru, etc and ended up back on base. At idle the noise was present when I was going to park the truck. Was not as obnoxious like when the pulley was screeching on the previous unit but the tone would change when the clutch would lock and unlock, but was present the entire time. Screech continues no matter the RPM and is present at idle.

 

Belt is only a few thousand miles old and is a Gates, same with tensioner (newer as well). I haven't gone through the other pulleys yet but will be doing so soon. I feel it would be a huge coincidence if another pulley decided to go 10miles after replacing the compressor and having no more squealing on the drive back... And there was a warning stating to make sure fan clutch was in working order  

To find a specific noise I use a rubber hose about 5/16" x 3ft.  You put one end against your ear and use the other end to search for the offending sound.  The hose can go around conners and behind moving parts with no worries; if it touches a moving part, like the fan, it will be pushed aside with no damage to the part.   

2 hours ago, YeaImDylan said:

tone would change when the clutch would lock and unlock, but was present the entire time. Screech continues no matter the RPM and is present at idle.

 

This condition indicates to me that the problem is not the compressor.  There are two different bearings sets involved with the compressor / clutch assembly.  When the compressor clutch is disengaged, the only bearing that is rotating is the clutch to input shaft bearing.   When the compressor clutch is engaged the clutch to input shaft bearing stops rotating and the front bearing inside the compressor begins rotating.  If one of these bearing is faulty, then the noise should disappear either when the compressor is engaged or disengaged.

 

It sounds to me that the noise is coming from another component or the belt.  The noise pitch changes when the AC compressor cycles on and off because the belt load is changed.

 

Since the noise is also occurring at idle, I would spray some WD-40 onto the belt (carefully) while the engine is running.  If the noise does not change significantly or go completely away, then I would think the belt is not the problem, but a belt driven component is the problem. 

 

In my experience over the years, belts can make horrendous noises that would make you look elsewhere, especially if any coolant has dripped onto the belt. 

 

I also think that it is worth removing the belt and try rotating and moving every pulley side-to-side and forward / backward to observe anything out of the ordinary.

 

- John

 

 

 

 

 

 

I've had varying degrees of bearing failure sound over the last 5 years. I once changed the water pump and the idler pulley at the same time only to have it come back squeaking at me again.Drove me nuts since the truck only has 115,000 on it. The belt was new so it was not changed until Tractorman told me it sounded like the belt. To me it sounded just like a bad bearing. I don't know how he knew it WAS, because when changed the belt back to an older one kept under the rear seat as a test the squeak is now gone. Was a surprise to me because everytime I had this noise on my first gen, about 3 times, it was the idler pulley but, this time it was the belt. Thank you Tractorman.

 @Tractormanwhat brand of belt do you buy? Thank you.

Not sure of the belt brand, but I did buy it from Geno's in October of 2014.  That belt has currently logged about 165,000 miles.  Just inspected it and all of the pulleys about three days ago.  All in good condition and the belt is still quiet.

 

- John

On 8/5/2023 at 10:54 PM, Tractorman said:

Not sure of the belt brand, but I did buy it from Geno's in October of 2014.  That belt has currently logged about 165,000 miles.  Just inspected it and all of the pulleys about three days ago.  All in good condition and the belt is still quiet.

 

- John

So, turned the truck on the other day and no squeaking/bearing noise/belt noise whatever it is. Upon driving, the noise came back and is there whether the compressor is going or not. A/C is also not blowing as cold as it was the day we installed it. We had the whole vacuum gauge setup for high and low side etc and everything was good to go reading wise. Just had surgery today so I won't be out troubleshooting for a few days but I will look into just replacing the belt and also listening to all pulleys. 

 

Sound will come back after idling for a bit WITHOUT engaging A/C.. so may just be the belt or maybe alternator or fan clutch pulley. Still doesn't explain why the AC is now cycling fast when I do have it on and it isn't getting as cold as it was the very first day we installed it. Also had done a leak test and she held vacuum at 30 mercury for like 30min before we went ahead and filled the system with 2.5-3 cans. I won't be able to get gauges back on it til this weekend depending on how I'm feeling.

Did you try spraying the belt with WD-40 while it's running and squeeking?

 

I'd guess you might have a valve leaking where the guages hook up. Sealed and holding pressure when hooked up but then leak slowly with nothing on them.

Agree  with @Max Tuneabout either of the valves leaking, especially the high pressure valve.  Spray with soapy water to detect a leak and then blow the fitting dry with compressed air before installing the protective cap.

 

Rapid compressor cycling strongly suggests a refrigerant leak.

 

When you get back to the truck, don't forget to test the serpentine belt noise with WD40.

 

- John

10 hours ago, Tractorman said:

Agree  with @Max Tuneabout either of the valves leaking, especially the high pressure valve.  Spray with soapy water to detect a leak and then blow the fitting dry with compressed air before installing the protective cap.

 

Rapid compressor cycling strongly suggests a refrigerant leak.

 

When you get back to the truck, don't forget to test the serpentine belt noise with WD40.

 

- John

Will do John! Thank you for your replies.

 

We replaced all but the evaporator and did the leak test so I'm honestly baffled it's probably leaking since it held vacuum fine for over 10min without moving from 30 hg. New sensors as well for high and low side. We filled the system with oil as well that is UV detection so I will also shine a light over all components. Maybe something didn't seat right when clamping together the tubes and whatnot and it didn't fully blow off or something. 

14 hours ago, Max Tune said:

Did you try spraying the belt with WD-40 while it's running and squeeking?

 

I'd guess you might have a valve leaking where the guages hook up. Sealed and holding pressure when hooked up but then leak slowly with nothing on them.

Not yet as I'm still recovering from surgery and also need to drive to my friend's house to do some of these tests. I hope it's not the valves since they were brand new lines!

I've got to ask did you add the right amount of PAG-100 oil to the compressor? IIRC the 2nd Gen 24V holds 5 or 6 ozs of PAG-100 oil. This can be added through the plug in the side of the body. I'm seeing some compressors being tagged with a label stating that the compressor is pre-loaded with 3 ozs of oil from the factory so make sure you subtract that from the total oil that you add. Excessive oil will decrease the A/C performance also you might hydro-lock the compressor and might vent pressure and oil out the back blow-off vent. 

 

WARNING: Don't pull the plug on the compressor while charged you will regret that quickly. Not to mention the plug I think is against the block side.

 

WARNING: Excessive amount of oil could cause the compressor to explode. This could be very damaging I've seen a tech video of a VW that exploded and distroyed the headlight and lots of other stuff.

 

As for the amount of charge, I typically look for 35 to 40 PSI on the low side and about 210 to 270 PSI high side based on outside temperatures. I always tell my clients to put the vehicle out in the sun. Then let the cab get nice and hot this way I can charge it for its working conditions and typically I can get the output temperatures much lower. But if the compressor is cycling that's a sign of being undercharged and hitting the low-temperature limit and it will kick out the compressor. 

 

As for sounds. I like some of the guy's suggestions like spraying the belt with a bit of WD-40 and seeing if the sound changes. As for bearing noises I typically would pull the belt and feel for rough bearings. Even @IBMobile idea of the hose is great and would allow you to listen for bearing noise. Still, be careful working around moving parts.