R4 A/C compressor noise

name · Aug 22, 2019

Hi guys,

I have a new to me 1994 GMC suburban with 100k miles that has a " clacking " noise coming from the ac pump when the AC is on. I have checked the aluminum housing mounting bolts and they are all present and tight. I have checked the idler pulley and it makes no sound consistant with a bad bearing. The clacking noise is constant and does not change with engine RPM

I have also pulled the clutch and pulley and although there was some grease and junk that apparently came from the bearing, and there was some play in the bearing the bearing does not catch or make a whirling sound when spun by hand or when the motor is running with AC off. after cleaning and re-instaling the clutch assembly the noise got a little louder.

I have read many threads about these R4s but am still confused on what to do to fix it. The sound I am talking about is the same as in this y-tube video. Unfortunatly, the person who posted this video did not make a comment on what he did to fix his condition.

can someone here who has gone threw this before tell me if changing out the clutch assembly and pulley will fix this condition, or what I must do to fix this noise. The AC does blow cold and seems to work fine .

Many Thanks,

xc_hide_links_from_guests_guests_error_hide_media

studigggs · Aug 22, 2019

The original R4 on my '90 sounded about that loud its whole life. lasted until 2013.

PlayingWithTBI · Aug 22, 2019

Did you set the air gap on the clutch? It s/b .020" - .030". These clutches are pressed on (no shims), just tightening the nut won't set it. However, this may not fix your issue, some R4's are noisy and some are nice and quiet, quality control?

bugdewde · Aug 23, 2019

Holy crap, that's loud. I'm toying with my A/C system and found this while googling my symptoms......….

May help with your issue. Not sure if it's relevant but might point in the right direction.

Knocking noise ….
https://www.thetruckstop.us/forum/t...s-it-has-a-thermal-expansion-valve-txv.23287/

Schurkey · Aug 23, 2019

name said:
The clacking noise is constant and does not change with engine RPM

If it doesn't change with RPM, it's not the compressor. The compressor is driven by a belt to the engine crankshaft pulley, if the engine speeds up, the compressor speeds up.

name · Aug 23, 2019

PlayingWithTBI said:
Did you set the air gap on the clutch? It s/b .020" - .030". These clutches are pressed on (no shims), just tightening the nut won't set it. However, this may not fix your issue, some R4's are noisy and some are nice and quiet, quality control?

I did set the air gap, but for some reason it seems tighter on one side than the other. the gap is .030 on the skinny side and about .060 on the big side. ( with the belt attached ) I wonder if the play in the bearing is to blame for the difference ?

name · Aug 23, 2019

bugdewde said:
Holy crap, that's loud. I'm toying with my A/C system and found this while googling my symptoms......….

May help with your issue. Not sure if it's relevant but might point in the right direction.

Knocking noise ….
https://www.thetruckstop.us/forum/t...s-it-has-a-thermal-expansion-valve-txv.23287/

This is a good read, My AC control on the upper console is set to the off position for the rear AC. I wonder if simply turning it on would eleviate the problem. I wonder why they even put a switch to turn it off if doing so would harm the system . If I need to replace the compressor, I wonder If I could just delete the rear AC ? any suggestions from those who have done so ?

bugdewde · Aug 24, 2019

I'm not sure I'd delete it …. it does come in handy to cool down the interior faster..... Like the thread stated, I'd just turn it on low or medium to help keep the evap from loading up and not let the refrigerant pool up in the long return line. Seems to make sense to me.
Since your compressor is probably sluffing metal off the cylinders, it's collecting in the orifice tubes …. I think that might be one if my issues posted in "Weird HVAC Issues". Seeing higher low-side pressures and lower High-side pressures. Might be a blockage somewhere. Orifice tubes? A/C blows cold, but occasionally blows warm …. frozen rear evap, from not running rear air ????? Could be.....

name · Aug 25, 2019

Well, I went ahead and change out the clutch but it did not have a effect on the noise. Here is a video I made of my situiation, let me know if you guys have any suggestions on what to do from here.

xc_hide_links_from_guests_guests_error_hide_media

honkon · Aug 26, 2019

My Yukon has the later style compressor, looks nothing like yours, but it makes a very similar noise. A clacking, rattling, knocking sort of sound. Sounds internal to the compressor. Seems sort of like a "rod knock" or piston slap or whatever.
Much quieter than the one in the video. It gets louder the lower it is on refrigerant, but not as loud as the vid. I can't get it to suck a full charge in from cans anyway, seems like the compressor is too worn out to generate enough suction. AC performance is sub par but good enough.

R4 A/C compressor noise

name

OBS Enthusiast

studigggs

I'm Awesome

PlayingWithTBI

2022 Truck of the Year

bugdewde

I'm Awesome

Schurkey

Supporting Member

name

OBS Enthusiast

name

OBS Enthusiast

bugdewde

I'm Awesome

name

OBS Enthusiast

honkon

OBS Enthusiast

Similar threads

Latest posts

Staff online

Members online

Forum statistics

Share this page