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Discussion Starter · #1 ·
Hi, I just worked on recharging my A/C yesterday, I did not get a recharge done though due to loud squealing noise when the compressor clutch engaged.

Basically, I will get the screaming squealing whenever the compressor clutch is engaged, even during the recharging. But once I turn the A/C button to off, everything becomes normal, and the car has no squealing when AC is off and drive normally.

I searched our forum, seems it is either caused by a loose belt or a bad compressor clutch. I understand the belt one, but I don't understand the clutch one.

Is the bad compressor clutch meaning it freezes when engaged? The sound is very loud, sounds like something will explode.

I know the AC compress bearing is a little rattling when I took off it and turn it by hand before, so I am thinking just to replacing the ac compressor directly and then adjust the belt for sure to fix it, am I on the correct direction?

Thanks!
 

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THE OhioSpyderson
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Hi, I just worked on recharging my A/C yesterday, I did not get a recharge done though due to loud squealing noise when the compressor clutch engaged.

Basically, I will get the screaming squealing whenever the compressor clutch is engaged, even during the recharging. But once I turn the A/C button to off, everything becomes normal, and the car has no squealing when AC is off and drive normally.

I searched our forum, seems it is either caused by a loose belt or a bad compressor clutch. I understand the belt one, but I don't understand the clutch one.

Is the bad compressor clutch meaning it freezes when engaged? The sound is very loud, sounds like something will explode.

I know the AC compress bearing is a little rattling when I took off it and turn it by hand before, so I am thinking just to replacing the ac compressor directly and then adjust the belt for sure to fix it, am I on the correct direction?

Thanks!
Likely the belt tension being too loose.

Take a look at this writeup to see how where to tension. It's sort of a trial and error thing.

Stealth 316 - AC Compressor Replacement

  1. Have the car on jack stands, tighten a few turns (and pulley)
  2. Restart/rev the car
  3. If still squealing, repeat 1&2

I also saw you were looking to replace the compressor all together? If so, you can follow that writeup as well but an easier method is to take the radiator and lay it on top of the valve cover leaving all the hoses attached.

It opens up WAY more room to access the compressor/hoses without removing the alternator. Either way isn't too bad, but I've found this to be much simpler and can pull the compressor straight up and out.

- Zach
 
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As above, the pump/compressor is not spinning and the belt is slipping on the pulley.

Either
a: The pump is seized
b: The belt is loose
c: The pump is seizing up while the A/C system is operating due to a system fault (e.g. condenser fans not working)
d: The pump has hydrolocked due to impropper recharging procedure.

With the engine off, see if you can reach in by hand and spin the center part of the A/C pump.
 

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Discussion Starter · #4 ·
As above, the pump/compressor is not spinning and the belt is slipping on the pulley.

Either
a: The pump is seized
b: The belt is loose
c: The pump is seizing up while the A/C system is operating due to a system fault (e.g. condenser fans not working)
d: The pump has hydrolocked due to impropper recharging procedure.

With the engine off, see if you can reach in by hand and spin the center part of the A/C pump.
Thanks, if this is the Case.3, is there any way to test the condenser fan? and will the compressor can be freed from seizing if the condenser fan back to work ?
 

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Discussion Starter · #5 ·
As above, the pump/compressor is not spinning and the belt is slipping on the pulley.

Either
a: The pump is seized
b: The belt is loose
c: The pump is seizing up while the A/C system is operating due to a system fault (e.g. condenser fans not working)
d: The pump has hydrolocked due to impropper recharging procedure.

With the engine off, see if you can reach in by hand and spin the center part of the A/C pump.
I don't know if the recharge procedure caused it. What happens is it is good when begins to recharge. but when the high pressure go to about 100, it starts to squeal, then becomes more and more loud, then I have to turn off the engine to avoid any further damage. But when I turn AC off, all become normal.
 

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Discussion Starter · #6 ·
And there is also another wired thing when I push the AC button, I have to push it twice then I can get the light on, seems the first push will make the button go deep to a first click then nothing happen, then I have to push the button deeper and get the second click, then its lights on...any thought?
 

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Both condenser/radiator fans should turn on when the A/C is switched on.

If the condenser fans don't work, the high side pressure gets to a point where the pump becomes very hard to turn and the belt slips (or a hose blows up or the pump explodes or something spectacular like that). Once the system is turned off and the pressures return to normal, the pump should free up again.

It's not uncommon for the oil to boil inside the pump in situations like this which can damage or destroy the pump over time.
 

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93 NA ATX 3000gt DOHC
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I am thinking just to replacing the ac compressor directly and then adjust the belt for sure to fix it, am I on the correct direction?
Tighten the belt! It's not uncommon for belt to squeal when A/C comes on if belt not tensioned tight enough, the A/C compressor is heaviest load.
Is the bad compressor clutch meaning it freezes when engaged? The sound is very loud, sounds like something will explode.
A bad clutch won't freeze when engaged, bad clutch bearing will rattle or squeal with engine running and A/C not on. Or not engage the compressor when A/C switched on. However, a frozen compressor will cause belt to sequel when clutch engages or a improperly tensioned belt.
 

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Hi, I just worked on recharging my A/C yesterday, I did not get a recharge done though due to loud squealing noise when the compressor clutch engaged.

Basically, I will get the screaming squealing whenever the compressor clutch is engaged, even during the recharging. But once I turn the A/C button to off, everything becomes normal, and the car has no squealing when AC is off and drive normally.

I searched our forum, seems it is either caused by a loose belt or a bad compressor clutch. I understand the belt one, but I don't understand the clutch one.

Is the bad compressor clutch meaning it freezes when engaged? The sound is very loud, sounds like something will explode.

I know the AC compress bearing is a little rattling when I took off it and turn it by hand before, so I am thinking just to replacing the ac compressor directly and then adjust the belt for sure to fix it, am I on the correct direction?

Thanks!
Agreed with everything said here
(Branched off of another thread)
 

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93 NA ATX 3000gt DOHC
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Both condenser/radiator fans should turn on when the A/C is switched on.
Do you mean both fans will immediately on once the ac button has been turned on?
That's true on 91-93 cars, but after that the system was changed to ECU control and wiring doesn't show that the radiator (right) fan will come on automatically when A/C turned on just condenser (left) fan in low speed, and maybe when it shifts to high speed the right radiator fan also gets triggered. :unsure:
 

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Discussion Starter · #13 ·
That's true on 91-93 cars, but after that the system was changed to ECU control and wiring doesn't show that the radiator (right) fan will come on automatically when A/C turned on just condenser (left) fan in low speed, and maybe when it shifts to high speed the right radiator fan also gets triggered. :unsure:
But the condenser fan will immediatly on once ac on right?
 

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But the condenser fan will immediatly on once ac on right?
Wondering same thing because condenser will heat up you will see this in the gauges on high side peak out (Or Retard out)
From the fan not cooling the condenser higher heat range higher pressure
AC won't work correctly
You'll have a 10 second chill factor then blow hot air thru vents dead give away for a fan not working
 

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To much pag oil in system ac wont cool correctly either
also seen in the gauges
But you'll have to see it digitally metered in recharge knowing the exact amount recharged

Systems in higher elevations will need more freon just FYi up to half a pound to 3/4 lb more freon then rated by manufacturer specs
Doing 0.10 at a time till you achieve measurements in the gauges ....
Charge high side with engine off
Charge low side with engine on (AC on)

(AC on)
Low side engine on (suction) BLUE coupler
High side engine on (pressure) RED coupler
 

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But the condenser fan will immediatly on once ac on right?
Yes in low speed, as long as everything is correct with Air Conditioning Compressor Lock Controller (ACCLC). It supplies power to control side of condenser low speed fan relay which will close as soon as power is received and condenser fan will run as long as 20amp #8 dedicated fuse (in small A/C relay box near drier) is good.

I suspect everything is OK with the ACCLC, because compressor clutch wouldn’t engage if there was a problem there. That’s another reason I think your squealing is a belt not tight enough and not a stuck compressor, because there’s a rotation sensor on compressor that ACCLC unit monitors and if it doesn’t sense rotation when clutch engages, it will immediately dropout compressor clutch.
 

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Discussion Starter · #17 ·
Yes in low speed, as long as everything is correct with Air Conditioning Compressor Lock Controller (ACCLC). It supplies power to control side of condenser low speed fan relay which will close as soon as power is received and condenser fan will run as long as 20amp #8 dedicated fuse (in small A/C relay box near drier) is good.

I suspect everything is OK with the ACCLC, because compressor clutch wouldn’t engage if there was a problem there. That’s another reason I think your squealing is a belt not tight enough and not a stuck compressor, because there’s a rotation sensor on compressor that ACCLC unit monitors and if it doesn’t sense rotation when clutch engages, it will immediately dropout compressor clutch.
Thank you, sir, I ordered a tensioner gauge, it will come today, then I will start from the belt.
 

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Discussion Starter · #18 ·
Yes in low speed, as long as everything is correct with Air Conditioning Compressor Lock Controller (ACCLC). It supplies power to control side of condenser low speed fan relay which will close as soon as power is received and condenser fan will run as long as 20amp #8 dedicated fuse (in small A/C relay box near drier) is good.

I suspect everything is OK with the ACCLC, because compressor clutch wouldn’t engage if there was a problem there. That’s another reason I think your squealing is a belt not tight enough and not a stuck compressor, because there’s a rotation sensor on compressor that ACCLC unit monitors and if it doesn’t sense rotation when clutch engages, it will immediately dropout compressor clutch.
And you're right, the condenser fan will be on immediately if I turn on the A/C, the tensioner gauge just arrived but I can not use it on the belt...too big, so do you have some tricky tool to check/adjust belts?
 

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the tensioner gauge just arrived but I can not use it on the belt...too big, so do you have some tricky tool to check/adjust belts?
No tricky tool, below is factory tension method. That belt tension is tighter than you probably imagined.

You can view this process in below video, view section from 17:30 to 19:43 mins.

 

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Discussion Starter · #20 ·
No tricky tool, below is factory tension method. That belt tension is tighter than you probably imagined.
View attachment 303921
You can view this process in below video, view section from 17:30 to 19:43 mins.

Thank you, sorry for one last question, I probably got the same issue from my power steering pump, the steering wheel is really heavy now, particularly in low speed, but I just got the rack replaced, the whole system flushed, and even a full alignment..., so I am thinking it did not get the belt to tighten enough.

Here is what I did, I just tight the ps belt with the longest slack can be twisted 90 degree, is this enough? or our car should be righter than this? Thanks!
 
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