Problem with A/C compressor randomly not engaging

I would first measure if you are getting voltage to the clutch.

If you are getting voltage to the clutch and it's not engaging, it's a clutch problem. If you are getting voltage and it IS engaging, but not getting cold, hmm... If you are not getting voltage when you should, it is another possible set of problems, such as a bad pressure switch or relay.
 
Chris142 said:
that gap is HUGE! That is your problem. I cant remember if you need a puller to remove the hub or not.
Click to expand...
Chris is 100% correct. If you don't have the proper feeler gauge, you can try folding an index card in half and using it as a rough feeler gauge. Once you bolt out of the shaft, be careful removing the faceplate so that you don't lose any of the washer shims.
 
brages said:
I would first measure if you are getting voltage to the clutch.

If you are getting voltage to the clutch and it's not engaging, it's a clutch problem. If you are getting voltage and it IS engaging, but not getting cold, hmm... If you are not getting voltage when you should, it is another possible set of problems, such as a bad pressure switch or relay.
Click to expand...
The problem occurs randomly and so far relatively rarely. I have to wait for it to happen in order to take a measurement.

Chris142 said:
that gap is HUGE! That is your problem. I cant remember if you need a puller to remove the hub or not.
Click to expand...
It seems so, but if you open the image on a new tab on your browser and zoom it, I have the impression that the gap is huge only at the circumference of the clutch and then it gets tighter. Of course maybe I'm wrong and just mislead by the photo. If it does not get tighter indeed it is very wide. Even though most of the time the compressor engages without an issue. I would say that the problem occurs less than 10% of the time the A/C is turned on.

Nukeman7 said:
Chris is 100% correct. If you don't have the proper feeler gauge, you can try folding an index card in half and using it as a rough feeler gauge. Once you bolt out of the shaft, be careful removing the faceplate so that you don't lose any of the washer shims.
Click to expand...
I don't own a feeler gauge and right now I'm on vacation so I won't fix it immediately. I may ask around for one though in order to take a measurement.

By the way, in order to adjust the gap the work probably has to be done on the bench, right? That means that the refrigerant lines are going to get disconnected from the compressor. Do I have to use new o-rings (or whatever) the system is using as a sealant for the lines?
 
inquirer said:
It seems so, but if you open the image on a new tab on your browser and zoom it, I have the impression that the gap is huge only at the circumference of the clutch and then it gets tighter. Of course maybe I'm wrong and just mislead by the photo. If it does not get tighter indeed it is very wide. Even though most of the time the compressor engages without an issue. I would say that the problem occurs less than 10% of the time the A/C is turned on.
Click to expand...
The air gap is measured with the appropriate size feeler gauge at the gap at the circumference/edge of the face plate. Your photo clearly shows the gap void space is too excessive.
inquirer said:
I don't own a feeler gauge and right now I'm on vacation so I won't fix it immediately. I may ask around for one though in order to take a measurement.

By the way, in order to adjust the gap the work probably has to be done on the bench, right? That means that the refrigerant lines are going to get disconnected from the compressor. Do I have to use new o-rings (or whatever) the system is using as a sealant for the lines?
Click to expand...
No, no, no!!! Do not remove the compressor or disconnect the refrigerant lines! Just remove the 10 mm bolt that is holding the faceplate to the shaft and wiggle/slide the plate off of the splined shaft, being careful to catch the washers. I normally remove the bolt and insert a thin screwdriver into the shaft cavity to prevent the washer shims from dropping into the engine bay when removing and installing the face plates. Watch this video before attempting the adjustment.



You might need to figure out how to keep the face plate & shaft from rotating when you un-thread & reinstall the 10 mm bolt. This special tool is what I use to hold the face plate from turning; however, it is often not necessary if you can use an impact wrench on the bolt.

1723649800872.jpg
 
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Nukeman7 said:
The air gap is measured with the appropriate size feeler gauge at the gap at the circumference/edge of the face plate. Your photo clearly shows the gap void space is too excessive.
Click to expand...
If the measurement is taken at the circumference then definitely we are talking about a gap over 0.04 inches.

Nukeman7 said:
No, no, no!!! Do not remove the compressor or disconnect the refrigerant lines! Just remove the 10 mm bolt that is holding the faceplate to the shaft and wiggle/slide the plate off of the splined shaft, being careful to catch the washers. I normally remove the bolt and insert a thin screwdriver into the shaft cavity to prevent the washer shims from dropping into the engine bay when removing and installing the face plates. Watch this video before attempting the adjustment.
Click to expand...
Oh, OK! In that case the work is simpler compared to having to disconnect the lines, with the exception of course of the restricted workspace..
 
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inquirer said:
The problem occurs randomly and so far relatively rarely. I have to wait for it to happen in order to take a measurement.


It seems so, but if you open the image on a new tab on your browser and zoom it, I have the impression that the gap is huge only at the circumference of the clutch and then it gets tighter. Of course maybe I'm wrong and just mislead by the photo. If it does not get tighter indeed it is very wide. Even though most of the time the compressor engages without an issue. I would say that the problem occurs less than 10% of the time the A/C is turned on.


I don't own a feeler gauge and right now I'm on vacation so I won't fix it immediately. I may ask around for one though in order to take a measurement.

By the way, in order to adjust the gap the work probably has to be done on the bench, right? That means that the refrigerant lines are going to get disconnected from the compressor. Do I have to use new o-rings (or whatever) the system is using as a sealant for the lines?
Click to expand...
if you can do it in the car thats fine
 
I took the one out of my V8 Taurus SHO in the car, probably less than 2" from the fender.. Really took some long and double jointed extensions but managed pretty easily. One very thin shim and it worked OK. It would not engage when hot at highway speeds. So I'd be driving along and the AC would drop out. Slow down and cycle the AC and it would come back on.
 
@D60 & @Nukeman7

Of course feeler gauges are widely available in Greece too. I may buy one, but I have to see what is available regarding the number of blades and the steps between them.
 
I bet in a lot of applications you could use a spark plug gap gauge. You don't necessarily need exact numbers; a ballpark go/no-go is good enough, ie if 30 fits and 40 doesn't, you know you're somewhere in that range. If you adjust and 30 now fits with slight drag, you're probably at .030" give or take a couple thou (I'm assuming the outer plate will deflect a bit so you may be able to insert a thickness greater than the uniform air gap at rest)

Or whatever.
 
D60 said:
I bet in a lot of applications you could use a spark plug gap gauge. You don't necessarily need exact numbers; a ballpark go/no-go is good enough, ie if 30 fits and 40 doesn't, you know you're somewhere in that range. If you adjust and 30 now fits with slight drag, you're probably at .030" give or take a couple thou (I'm assuming the outer plate will deflect a bit so you may be able to insert a thickness greater than the uniform air gap at rest)

Or whatever.
Click to expand...
Well, I think I would prefer a feeler gauge. I found one with 32 blades starting from 0.00079 inches and going up to 0.04 inches, with steps of 0.00039, 0.0012 and 0.002 inches. I think it is more than adequate for most applications.

By the way, I have a question regarding the compressor's clutch. Would it be a good idea to resurface it when I'm going to adjust the gap?
 
inquirer said:
Well, I think I would prefer a feeler gauge. I found one with 32 blades starting from 0.00079 inches and going up to 0.04 inches, with steps of 0.00039, 0.0012 and 0.002 inches. I think it is more than adequate for most applications.

By the way, I have a question regarding the compressor's clutch. Would it be a good idea to resurface it when I'm going to adjust the gap?
Click to expand...
Most A/C clutch faceplates and pulley mating surfaces are just steel. If you see rust or corrosion, you should gently remove it with a wire brush or a ScotchBrite pad. Be careful not to gouge the surfaces and blow out any residual debris with compressed air before reassembling the clutch. A few (rare) A/C clutches have a thin layer of organic friction material like brake pads. Do not disturb or remove any of the organic friction material if found; however, I've never seen this on an Asian vehicle.
 
Nukeman7 said:
Most A/C clutch faceplates and pulley mating surfaces are just steel. If you see rust or corrosion, you should gently remove it with a wire brush or a ScotchBrite pad. Be careful not to gouge the surfaces and blow out any residual debris with compressed air before reassembling the clutch. A few (rare) A/C clutches have a thin layer of organic friction material like brake pads. Do not disturb or remove any of the organic friction material if found; however, I've never seen this on an Asian vehicle.
Click to expand...
I know that they resurface flywheels when installing new clutch discs, if the flywheels are badly worn.

Anyway, on a second thought resurfacing only the clutch without resurfacing its mating surface probably is a bad idea and does not make much sense.

By the way, does the increased gap mean that the clutch or the pulley or both have worn out? Or does the gap change for other reasons?
 
inquirer said:
I know that they resurface flywheels when installing new clutch discs, if the flywheels are badly worn.

Anyway, on a second thought resurfacing only the clutch without resurfacing its mating surface probably is a bad idea and does not make much sense.

By the way, does the increased gap mean that the clutch or the pulley or both have worn out? Or does the gap change for other reasons?
Click to expand...
I believe the increase in the air gap is due to repeated miniscule abrasion wear on the mating surfaces as the clutch engages thousands of times over the lifespan of the vehicle. If the surfaces are bare metal (i.e., not the type with friction material), it will never wear out, unlike a flywheel that has a specified minimum thickness. I have never experienced (or even heard of) having to adjust the air gap more than once over the lifetime of any vehicle, although subsequent A/C clutch replacement may be needed if the coil burns out later.
 
Nukeman7 said:
I believe the increase in the air gap is due to repeated miniscule abrasion wear on the mating surfaces as the clutch engages thousands of times over the lifespan of the vehicle. If the surfaces are bare metal (i.e., not the type with friction material), it will never wear out, unlike a flywheel that has a specified minimum thickness. I have never experienced (or even heard of) having to adjust the air gap more than once over the lifetime of any vehicle, although subsequent A/C clutch replacement may be needed if the coil burns out later.
Click to expand...
I have seen them wear out to the point of being too thin. Not so common on cars but 18 wheelers very often.
 
Chris142 said:
No! its worn together as a set..
Click to expand...
Yes, if you read my previous post I mentioned that it doesn't make much sense to resurface just the clutch. If the clutch is going to get resurfaced obviously the pulley needs to get resurfaced too.

By the way searching online for the air gap specifications for the Lancer I found the following document: http://mmc-manuals.ru/msb/BASE/003/2014/MSB-14EXML55-001/E/MSB-14EXML55-001.pdf

It says that Mitsubishi revised the initial specs of the air gap from 0.25 - 0.45 mm (0.010 - 0.017 inches) to 0.15 - 0.4 mm (0.006 - 0.015 inches) in 2014.

edit: It seems that the aforementioned update excludes the 1500 model. For it the gap remains at the following range: 0.25 - 0.5 mm (0.010 - 0.020 inches).
 
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