ac compressor noise?

davey300 · 03-27-2009, 11:03 AM

i have a 98 f-150 4.6 auto, i have been hearing a loud noise sounds like the ac compressor, if it is low on oil will it make like a loud howling sound? it only lastes maybe a minute. it is still blowing cold air also, anyway to check it? thanks dave

bradrhale · 03-27-2009, 11:42 AM

if it was low on oil, you would have no freon and it would not be cooling assuming that this compressor is fairly old. does this noise happen at any given time, when cold, when warm??

davey300 · 03-27-2009, 12:00 PM

when it sits for a while, cold. the idler wheel sounds ok,alt,water pump. the sound is comming from the bottom around the ac compressor. thankd dave

Case 7230 · 03-27-2009, 12:04 PM

Are you sure it is not the belt tensioner pulley?
Sorry posted at the same time.

eponator · 03-27-2009, 12:11 PM

Double check those pulleys!

These sounds can be misleading and its as simple as removing the belt and rotating the pulleys by hand to determine if the bearings are still good or not.

Sometimes tightening the clutch bolts on the AC a little helps to make the sound dissapear but this is only a temp fix. If the A/C bearings or clutch are giving out its only a matter of time before the sound comes back and its worse than before!

Is the A/C or heater on when this sound presents itself or is it just on every cold startup regardless? Could also be the fan clutch, when they start to go they make a howling sound on cold startup too.

leolkfrm · 03-27-2009, 04:08 PM

use a piece of pvc pipe as a listening tool and find where it is coming from

hotrodpc · 03-27-2009, 05:19 PM

Leo borrows my redneck technology to listen for noises too? I knew I should have pattened that idea when I got it. I also use a sawed off wooden broom stick or a large 2ft long, thick screwdriver I have. Point is Dave, the noise will play tricks on you and be coming from somewhere you don't think it is, so you can isolate the noise by using a pvc pipe, broom stick whatever, and put it on the housing of each accessory ran by the belt, close to the front, and put your ear to whatever you are using and listen for bearing grinding or thumps. If you find it, you will know it right away.

davey300 · 03-27-2009, 06:12 PM

thanks so much for the help!! i appreciate it alot!!

dave

bradrhale · 03-27-2009, 07:16 PM

just be mindful where you put your stick while the engine is running. on every fan belt box, there is a caution sticker warning everyone to turn off engine before installation. no lie.

hotrodpc · 03-27-2009, 07:21 PM

Sounds like something my dad told me long long ago..... But on a serious note, great tip. It would be a serious injury if you goofed.

03-27-2009, 11:03 AM	#1
davey300 Full Member Join Date: Mar 2009 Posts: 15	ac compressor noise? i have a 98 f-150 4.6 auto, i have been hearing a loud noise sounds like the ac compressor, if it is low on oil will it make like a loud howling sound? it only lastes maybe a minute. it is still blowing cold air also, anyway to check it? thanks dave

03-27-2009, 12:04 PM	#4
Case 7230 Senior Member Join Date: Dec 2007 Posts: 547	Are you sure it is not the belt tensioner pulley? Sorry posted at the same time. Last edited by Case 7230; 03-27-2009 at 12:05 PM. Reason: new info

03-27-2009, 12:11 PM	#5
eponator Senior Member Join Date: Nov 2008 Location: West Covina, Ca Posts: 363	Double check those pulleys! These sounds can be misleading and its as simple as removing the belt and rotating the pulleys by hand to determine if the bearings are still good or not. Sometimes tightening the clutch bolts on the AC a little helps to make the sound dissapear but this is only a temp fix. If the A/C bearings or clutch are giving out its only a matter of time before the sound comes back and its worse than before! Is the A/C or heater on when this sound presents itself or is it just on every cold startup regardless? Could also be the fan clutch, when they start to go they make a howling sound on cold startup too. __________________ '99 F350 5.4L crewcab Longbed Last edited by eponator; 03-27-2009 at 04:37 PM.

03-27-2009, 04:08 PM	#6
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	use a piece of pvc pipe as a listening tool and find where it is coming from __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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03-27-2009, 11:42 AM	#2
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,024	if it was low on oil, you would have no freon and it would not be cooling assuming that this compressor is fairly old. does this noise happen at any given time, when cold, when warm??

03-27-2009, 12:00 PM	#3
davey300 Full Member Join Date: Mar 2009 Posts: 15	when it sits for a while, cold. the idler wheel sounds ok,alt,water pump. the sound is comming from the bottom around the ac compressor. thankd dave

03-27-2009, 05:19 PM	#7
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	Leo borrows my redneck technology to listen for noises too? I knew I should have pattened that idea when I got it. I also use a sawed off wooden broom stick or a large 2ft long, thick screwdriver I have. Point is Dave, the noise will play tricks on you and be coming from somewhere you don't think it is, so you can isolate the noise by using a pvc pipe, broom stick whatever, and put it on the housing of each accessory ran by the belt, close to the front, and put your ear to whatever you are using and listen for bearing grinding or thumps. If you find it, you will know it right away.

03-27-2009, 06:12 PM	#8
davey300 Full Member Join Date: Mar 2009 Posts: 15	thanks so much for the help!! i appreciate it alot!! dave

03-27-2009, 07:16 PM	#9
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,024	just be mindful where you put your stick while the engine is running. on every fan belt box, there is a caution sticker warning everyone to turn off engine before installation. no lie.

03-27-2009, 07:21 PM	#10
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,149	Sounds like something my dad told me long long ago..... But on a serious note, great tip. It would be a serious injury if you goofed.

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