Whining noise from engine bay

rmuller

rmuller

Well-known member
Apr 28, 2004
4,452
1
Northern NJ
www.njlr.org
I have a loud whining noise which I think is coming from the AC compressor... Here's a sound clip of it;

http://njlr.org/temp/engine.mp3 (apologies for the wind noise a couple seconds in) ...

is this something that warrants a replacement of the compressor? It's been sounding like that for a year or so now (7 of those months the truck wasn't driven)...
 
rmuller

rmuller

Well-known member
Apr 28, 2004
4,452
1
Northern NJ
www.njlr.org
I have a mechanics stethoscope and it definitely sounds like it's coming from the AC compressor... not sure if it's the compressor itself, the pulley (is it replaceable on its own?) or something else.
 
jymmiejamz

jymmiejamz

Well-known member
Dec 5, 2004
6,010
362
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Los Angeles, Ca
Do you have the updated metal idler pulley? If you still have the plastic one it probably has flat spots on it which causes a noise like that. It is directly below the ac compressor. The new pulley is only like $20 IIRC.
 
jymmiejamz

jymmiejamz

Well-known member
Dec 5, 2004
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Los Angeles, Ca
That should be the one. If you pull the belt off and feel the pulley it will be obvious if it is the problem. For some reason it will have flat spots all over it.
 
Discoinjapan

Discoinjapan

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Feb 14, 2006
2,526
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Yokosuka Japan via PA
I have yet to own a D2 but thats what my alt(D1) sounded like when it was shot. I think it was the brushes but dont know, I just bought a MM from Will and all is well.

Anyway like stated before take the belt of and check it out.
 
N

nolift911

Well-known member
Feb 19, 2006
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0
Is this when it is cold or warm? I have a whirring sound that goes up and down with the engine speed only when cold - have not been able to track it down. Problem is it goes away after about 2-3 miles or when the truck warms up so you get like 2 minutes to figure out and it slowly goes away during the warm up so like maybe 1 minute to try and track it. In addition to the engine thrashing at a higher idle since it is cold makes it tough to pinpoint. About all I got is center of the engine on top somewhere...

Thought it could be a vacuum leak somewhere...but does sound more pully related. I could pull the belt but that eliminates like 8 or so pulleys right?? Besides not sure why it goes away when warm, obviously something expanding but what?

Pretty annoying with something like this it is usually wait until it fully shows itself...ie something breaks or no longer works to get it identified.
 
KyleT

KyleT

Well-known member
Mar 28, 2007
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Fort Worth, TEXAS
the plastic one can eventually wear out and the belt can fly apart. i had one that wore the plastic completely off and all that was left was the web support under the round running surface, it was making a heck of a ratling noise but somehow the belt stayed on...
 
rmuller

rmuller

Well-known member
Apr 28, 2004
4,452
1
Northern NJ
www.njlr.org
mine happens on both cold & warm... all times, all rpms.... I replaced the left pulley a while back... so hopefully this is the right one... once this rain stops (probably tomorrow), i'll get a look at it.
 
pdogg

pdogg

Well-known member
Jul 18, 2005
1,216
29
Phoenix, AZ
I've had a whine in my engine bay for the past 3 years I can't fix... I've replaced every pulley.. no help..

I just live with it now... I still think it's my power steering pump... I did the fluid swap... didn't help much...
 
N

nolift911

Well-known member
Feb 19, 2006
403
0
rmuller said:
mine happens on both cold & warm... all times, all rpms.... I replaced the left pulley a while back... so hopefully this is the right one... once this rain stops (probably tomorrow), i'll get a look at it.
Click to expand...

Ah ok - sorry didn't want to hi-jack with my issue - which now seems different than yours.
 
V

varova87

Well-known member
Mar 21, 2006
3,558
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Texas
jymmiejamz said:
have you done anything to try to fix it?
Click to expand...

no, as far as i can tell, nothing is wrong. the whine is mostly from the interior, not so much noticeable from outside. PO used noisy lifters on a rebuild, so I just add the whine into the pot of other strange noises. Aside from overheating issues, car runs great. Will be checking the water pump today, though.
 
rmuller

rmuller

Well-known member
Apr 28, 2004
4,452
1
Northern NJ
www.njlr.org
Hmm I got a chance to look at it yesterday and it doesn't appear to be that 70mm pulley... its a metal pulley there, and it was tight as anything and didn't have any flat spots when turning it... the noise still seems to be coming from the AC compressor, but comes from it whether or not the clutch is engaged. I'm wondering if there is any way to further diagnose it... if I need to change out the compressor, I need a shop to vac the system, right?
 
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