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AC Compressor noise? How about alternator output? Updated with results


R Dubya
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Any of you guys ever turn down your radio when driving through town and able to hear the ac compressor? I am getting a sound from mine only when its engaged. It sounds like a slap or rub kind of, something definetely in the clutch as it only happens when engaged. Kind of a weird situation, it happened with the last reman compressor I put on, which did the same thing only a bit louder. I am a little concerned its going to implode in the system. I am wondering if this is common issue with these particular cars or if there may be something wrong with this compressor.

 

The alternator charge warning light comes on from time to time, but I know the alternator is charging, I am wondering if maybe the belt is causing an issue, or if it is possible the tensioner not gripping properly and possibly causing this noise with the ac on? Any experience from anyone?

 

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So far I support all your perspectives :cool:, and can only add that maybe the belt slipping is the sound you are hearing, and maybe is worse when the compressor is loading up the belt, evident when the Alternator Lights starts to glow, which is a sign the voltage is dropping i.e. from the belt slipping and not able to turn the alternator enough. Trick is to take a felt marker and run a few lines over the belt, then run the engine as well as the compressor for a short time, then shut off the engine and see if the felt mark had smeared or worn off, but it already sounds a given with what you said so far, so I would just get a new tensioner and belt and have these maintenance items all done.

 

Let us know how it goes, I am having some issues with my new AC Compressor, aside from the (disengaged) clutch scrapping sound there is a loud hum/vibration from the compressor or? when the AC is engaged and the engine is revved from 2,000 to 3,500 rpms. I even swapped in another new compressor and at the same time replaced the condenser, evap (quite plugged with dust, phuzz and such!), metering orifice and accumulator (that comes with an additional fitting so you don't have to bitch about trying to access the one buried over by the turbo :evil:) and added all the appropriate amounts of compatible oil. I have no Alternator Light on yet but am planning to replace my new tensioner after I first confirm slipping by using the same felt marker trick :lol:

 

Jeff M

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the humming/vibration noise you are describing is the same thing that I am experiencing, this is a 4 seasons unit with compatible GM PAG oil and the proper amount of refrigerant. This thing blows cold air when its going, but pops on and off from time to time, I think I have a bad connection at purge switch on the compressor. It is holding the charge fine and everthing, so I am thinking it has to be the belt or the tensioner, although tomorrow I will take the car to Advance Auto and have them check my alternator for proper charging. The battery did die a month or so ago, but I left it in all winter and it ran fine up until that time with no issues. I had also drained it a few times with the brake lights staying on, which is now fixed, but still might have drained its full CCA ability. Not that we have to worry about that around these parts, 100+ today. I will first check the alternator and then go from there, I think I have a spare belt I can use, and I may be going to a gatorback anyway if the price is decent. Thanks for the input I will post my findings, I will also be pricing out a tensioner as well.

 

 

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Oh good, we might have the same issue :smile: good sort of :lol:, and I will add my findings; that the first compressor I used was a Four Seasons, so the next one, that I am running now, is a GM unit made by Delphi, running R12 have Ester based oil that works for R12 and R134a and the 2.25lb charge though its not that cold so need to gauge it to be sure, but with all this and breaking the compressor in as it states; add oil to suction side and rotate by hand a few times, add proper amount of oil to compressor crankcase, then install unit and bump it on for a second or two then pause, bump it again then pause, do this a few times then all should run good so still concerned about the noise.

 

Not sure but just to mention, your bumping off and on might be the chip sensing your foot/TPS far enough to cause a disengage of the AC Clutch? Just checking :cool:

 

Did you measure the charge or go by gauge readings? R12 or 134a? I read you use less of the R134a for a full charge, if not then might be overcharged for the R134a and tripping the safety/HP Cut-out?

 

Yea I still hear that even with a gel cel battery that once drained its not going to ever come back to full CCA or RC ratings.

 

Jeff M

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I'm using r134a that I properly converted earlier this year with a new drier and condenser as the old one was beat. I replaced all the orings and everything and went with a 2 lb charge for the regfrigerant by the recommendation of a GM tech. In fact the last time I charged I put in less than 2 lbs of 3M in a can. I've been doing a lot of AC work this summer, on my truck, which is still leaking, don't know where, and my Dad's PT cruiser which had a blown compressor oring on the high side line. I think I put on a cheap-o belt when I did the motor 2 years ago, but it only has a couple thousand miles, but I wouldn't put it aside for sure until I can check it out. Usually it disengages when I turn the wheel hard either way, so this must really be an issue with the belt/tensioner.

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That's the same hum noise I've experienced in many late 80's :lol: GM vehicles including my own TGP with 39k miles. It was so bad in my Grandfathers 87-89 (can't remember that far back) Suburban that you didn't want to be in the vehicle with the air on. It literally vibrated/hummed you right out of the vehicle. I wonder if that's GM's reasoning for marketing the "Hummer" :lol:

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The other TGP I had with 160k on it had its original R12 charge and it was as quiet as a mouse. I paid nearly $2 bills for this "reman" unit and want to make sure I'm not getting stuck with a faulty rebuild. I've got a new drier and condenser and if this thing suffers the black death I will be extremely upset.

 

Oh why oh why can't anything be easy??? :lol:

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I'm using r134a that I properly converted earlier this year with a new drier and condenser as the old one was beat. I replaced all the orings and everything and went with a 2 lb charge for the regfrigerant by the recommendation of a GM tech. In fact the last time I charged I put in less than 2 lbs of 3M in a can. I've been doing a lot of AC work this summer, on my truck, which is still leaking, don't know where, and my Dad's PT cruiser which had a blown compressor oring on the high side line. I think I put on a cheap-o belt when I did the motor 2 years ago, but it only has a couple thousand miles, but I wouldn't put it aside for sure until I can check it out. Usually it disengages when I turn the wheel hard either way, so this must really be an issue with the belt/tensioner.

 

Thanks for the update on your setup :smile:. Not had any belts stretch that bad but that don't mean it cannot happen, so for now I think the tensioner, till I hear the belt can be that bad, then will make a new mental note on it :cool:

 

To make you happy, your compressor cutting out when the steering wheel is turned (GOOD noting on that bty!) is supposed to be that way, there is a pressure switch on the steering rack, and when the pressure gets high enough/when turning the wheel far enough, the computer will disengage the AC compressor clutch, in an attempt to keep the engine from being lugged down too far and maybe stalling :mrgreen:.

 

My 2 other TGPs that have stock compressors and do work properly do not hum like this, so there is still a mystery here to solve I think.

 

Jeff M

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The other TGP I had with 160k on it had its original R12 charge and it was as quiet as a mouse. I paid nearly $2 bills for this "reman" unit and want to make sure I'm not getting stuck with a faulty rebuild. I've got a new drier and condenser and if this thing suffers the black death I will be extremely upset.

 

Oh why oh why can't anything be easy??? :lol:

 

Oh you don't like challenges? :lol: I hear that :willynilly: so goes ownership of any car new or used, my wife's new car has had plenty of issues, but worse is you cannot control the guy fixing it or make him listen that it needs to be fixed or made right/proper, at least with us at the helm on fixing a car, we can and will get it right!

 

I paid $220 for the Four Seasons unit so the $200 you paid is a good price, my Delphi was $250 with a $750 retail, yea a service garage has lots of profit margin there :lol:.

 

Jeff M

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The other TGP I had with 160k on it had its original R12 charge and it was as quiet as a mouse. I paid nearly $2 bills for this "reman" unit and want to make sure I'm not getting stuck with a faulty rebuild. I've got a new drier and condenser and if this thing suffers the black death I will be extremely upset.

 

Oh why oh why can't anything be easy??? :lol:

 

Oh you don't like challenges? :lol: I hear that :willynilly: so goes ownership of any car new or used, my wife's new car has had plenty of issues, but worse is you cannot control the guy fixing it or make him listen that it needs to be fixed or made right/proper, at least with us at the helm on fixing a car, we can and will get it right!

 

I paid $220 for the Four Seasons unit so the $200 you paid is a good price, my Delphi was $250 with a $750 retail, yea a service garage has lots of profit margin there :lol:.

 

Jeff M

 

true dat.....I cant stand not having air in the car no more, so eating up this info for the DIY to tackle here soon. Im sooooo jealous :willynilly:

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Well I fired it up and took it over to Advance this morning to have the alternator checked, and it seems to be running fine. Here are some of the stats though, maybe I am wrong and should consider a replacement due to the light occasionally coming on. The volts maintained a straight 12.6 or higher, which I assume is right on, and the amps hovered around 10-12 when idling. When I kicked on the compressor however the amps dropped way down below 5 and for the most part stayed there, peaking once at 7.1 (according to their machine), but for the most part stayed between 4.5 and 6. Is that bad?

 

The peak output was 64.2 amps, and from my understanding the stock alternator is rated at 105 peak power. Do I need to consider a replacement alternator? I know the noise is coming from the compressor and I may consider changing it out with a replacement j/y unit if I can find one suitable. Any suggestions on tracking this noise from here?

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cs-130-D. the alt should put out more amps when its under a load. like when the battery is low or the ac kicks on. but they put out less when they get hot. or should I say they put out a little and get hot quick. the 130-D has internal fans that keep it cool. oh yea, bad grounds get them hot quick.

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Here's my two cents.... I have owned my tgp since new and have been through like 8 alternators.

Power amps for your sound system play a big part; brake lights & ac compressor clutch another.

Two of the worst things you can do is 1st, let your battery be low from either not using the car enough

or anything else that causes the battery to be run down & then letting the alt charge it up. 2nd, being in traffic on a hot day with everything running is not good either esp. since if you are at a stop it is likely your

brake lights are on & your car is only at idle. This is definitely an alternator killer because low rpm gives limited cooling & voltage which means more current & heat. Also the rebuilt alt. does not last as long as a new one.

If you do run the battery down it is best to charge it to full using a charger not the alt. One last thought;

I wonder at what rpm the alt is rated at 105 amps because there is no way they can put out this

current at idle? Also, if you have to charge a low battery with the alt, do not do it at idle.

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