Whirling Sound While AC is Turned On, Matches Up With RPM

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

JamesSam

Full Access Member
Joined
Feb 15, 2023
Posts
1,576
Reaction score
4,323
Location
VA
First Name
Sam
Truck Year
1987
Truck Model
Silverado V10
Engine Size
5.7 L 350 v8
It *** supposed to rain all day here but only for a few hours in the late afternoon. I managed to pop the hood and idle the truck then turnt the AC on and off. Definitely coming from the compressor or the compressor clutch. Now battling my inner thoughts as to when and which compressor to install. Doesn't seem like I will be able to just roll to an auto part store and pick one up around here. Gonna have to order one.

Do I buy new low end, reassembled low end, or go for AC Delco new or reassembled? They all cost a pretty penny.
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
2,496
Reaction score
4,492
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
I would try to get something good name brand so you Don't have to do this again for a while.
 

JamesSam

Full Access Member
Joined
Feb 15, 2023
Posts
1,576
Reaction score
4,323
Location
VA
First Name
Sam
Truck Year
1987
Truck Model
Silverado V10
Engine Size
5.7 L 350 v8
So I decided I was going to get AC Delco or "GM Parts" from Rock Auto. I saw a couple YToob videos on replacing compressors...trying to find one specific to 1987 is not so easy. Anyway, looking through the service manual and catching a few heads ups from install info, it looks like a bit more than just filling the compressor with PAG oil and replacing.

Is it necessary to empty the system of refrigerant, replacing orrifice tubes, receiver drier, o-rings, etc...?

Starting to make me think this could be on another level for me. I was planning to knock this out in a matter of hours or possibly over the course of a few days on and off as work and life will allow. I might need to turn this in to the pros at the garage and eat the labor. I would like to save the money though.
 

gmbellew

Full Access Member
Joined
May 27, 2018
Posts
1,211
Reaction score
1,277
Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
AC work on a square, where everything is accessible, isn't too bad. I'd also replace the orifice tube and accumulator/drier while the system is open. As long as the compressor hasn't failed and sent particles throughout the system, you shouldn't need to flush. But if you do need to flush, you can rent the tool for that if you have a compressor. You can borrow a vacuum and gauges from the auto parts store to pull a vacuum and recharge. Or have a shop pull the vac and recharge after you do everything else.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,341
Reaction score
8,514
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
You should replace the receiver drier ANYTIME the system is open,and of coarse replace the orings. On post 13 I told you find a receiver drier and a compressor before it blows up,just so you can avoid what @gmbellew mentioned above.
Dammmit it says whirling noise,I thought it said whirring noise,this changes everything.
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
2,496
Reaction score
4,492
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
If anything do the work replacing what you want yourself and have the shop just leak down and refill.
 

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,067
Reaction score
2,221
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
Did you try to take a long screwdriver and check for vibration around the compressor? I found a missing bolt was causing a lot of vibration noise I thought was a bad compressor clutch until my cousin wedged a screwdriver in between the compressor and the different mounts until it stopped. Turned out the M12 bolt on the bottom of the compressor was awol
 

JamesSam

Full Access Member
Joined
Feb 15, 2023
Posts
1,576
Reaction score
4,323
Location
VA
First Name
Sam
Truck Year
1987
Truck Model
Silverado V10
Engine Size
5.7 L 350 v8
Seems it may be just in the clutch? Sounds like the rings in the clutch are banging in to each other doesn’t it. @TX87R10 your last info inspired me to look for something obvious. Nothing seems loose like a bolt or bolts are missing. Entire compressor? just the clutch? Maybe this clip will call out to someone that has seen this exactly...
xc_hide_links_from_guests_guests_error_hide_media
 

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,067
Reaction score
2,221
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
Seems it may be just in the clutch? Sounds like the rings in the clutch are banging in to each other doesn’t it. @TX87R10 your last info inspired me to look for something obvious. Nothing seems loose like a bolt or bolts are missing. Entire compressor? just the clutch? Maybe this clip will call out to someone that has seen this exactly...
xc_hide_links_from_guests_guests_error_hide_media
Lol this is gonna sound crazy but are you sure the belt isn't hitting the front bracket? I know that sounds crazy but I swear I see it slapping it and some wear on the bracket
You must be registered for see images attach


Probably the clutch or smth like you mentioned but figured I would mention just in case.
 

JamesSam

Full Access Member
Joined
Feb 15, 2023
Posts
1,576
Reaction score
4,323
Location
VA
First Name
Sam
Truck Year
1987
Truck Model
Silverado V10
Engine Size
5.7 L 350 v8
Lol this is gonna sound crazy but are you sure the belt isn't hitting the front bracket? I know that sounds crazy but I swear I see it slapping it and some wear on the bracket
You must be registered for see images attach


Probably the clutch or smth like you mentioned but figured I would mention just in case.
Ok. So possibly I just need to adjust the bracket and get a new serpentine eh? Re- watching my vid....
 

WFO

Full Access Member
Joined
Jan 6, 2017
Posts
3,673
Reaction score
5,014
Location
Texas Panhandle
First Name
Dan
Truck Year
1986
Truck Model
K20
Engine Size
350
Ok. So possibly I just need to adjust the bracket and get a new serpentine eh? Re- watching my vid....
I'd start by just tightening the belt first.
Does the belt show any signs of wear?
And it's called a V-Belt.
 

JamesSam

Full Access Member
Joined
Feb 15, 2023
Posts
1,576
Reaction score
4,323
Location
VA
First Name
Sam
Truck Year
1987
Truck Model
Silverado V10
Engine Size
5.7 L 350 v8
It does seem a little bit frayed. I was not even thinking or looking for the belt slapping something. I have just been staring at the compressor and the clutch the whole time. Watching my video back, it definitely is loose more than just running and flops out noticeably when the AC gets turned on. Thanks SB crew. I will get back after tightening the "V belt"...can you tell a guy that doesn't know directly off hand how to do that?
 

TX87R10

Full Access Member
Joined
Jun 25, 2020
Posts
1,067
Reaction score
2,221
Location
Texas
First Name
Txr10
Truck Year
1987
Truck Model
R10
Engine Size
305
It does seem a little bit frayed. I was not even thinking or looking for the belt slapping something. I have just been staring at the compressor and the clutch the whole time. Watching my video back, it definitely is loose more than just running and flops out noticeably when the AC gets turned on. Thanks SB crew. I will get back after tightening the "V belt"...can you tell a guy that doesn't know directly off hand how to do that?

I use a 1/2" breaker bar in the square hole you see on top, loosen the bolts mounting compressor to brackets, give it a good pull, and tighten them back up.
 
  • Like
Reactions: WFO

WFO

Full Access Member
Joined
Jan 6, 2017
Posts
3,673
Reaction score
5,014
Location
Texas Panhandle
First Name
Dan
Truck Year
1986
Truck Model
K20
Engine Size
350
It does seem a little bit frayed. I was not even thinking or looking for the belt slapping something. I have just been staring at the compressor and the clutch the whole time. Watching my video back, it definitely is loose more than just running and flops out noticeably when the AC gets turned on. Thanks SB crew. I will get back after tightening the "V belt"...can you tell a guy that doesn't know directly off hand how to do that?
Loosen the pivot bolt on the bottom bracket.
Then slightly loosen the bolt that's able to slide in the top bracket.
Tighten the belt a little more than it is, with a prybar or big screwdriver, while retightening the top bolt.
It will stay in place without the prybar now. Then tighten the pivot bolt.
 

Latest posts

Forum statistics

Threads
44,015
Posts
947,869
Members
36,083
Latest member
micacorn
Top