AC question

[SHOmaniac1975]

My ac in my 92 mtx blows ice cold for about 10 minutes then turns warm, if i turn the car off for ten minutes it blows cold again.
I had the system deep vac and retro fitted to 134a, high and low pressure switch was tested and said to be fine, yet the problem persists, any thoughts?

Thanks

 

[SHOtimer]

Your compressor clutch most likely needs to be adjusted. Their is a writeup on www.shotimes.com or just search this forum for adjusting the AC clutch gap.

Doug

 

[Ishodu]

Your compressor clutch most likely needs to be adjusted. Their is a writeup on www.shotimes.com or just search this forum for adjusting the AC clutch gap.

Doug

I agree. Once the system stop blowing cold you can look down at the compressor and see that the clutch is not engaged. If you give it a tap with something it will start going, then this is your problem.

 

[pjtoledo]

Those symptoms are the same as a bad field coil in the AC clutch. The engine heat migrates to the coil. A bad internal connection expands and looses electrical connection. Once cooled off it starts working again. To further isolate the problem, try driving at 80-85 for a while. At that speed the air will cool the AC coil and it will start working again. When my 92 did that it was kind of tough to verify the failure. I spliced into the wire harness and ran wires to a test meter in the cabin so I could monitor it while driving.

Perry

 

[rangerj]

The clutch gap should be about .035. If greater than that correct it. If the problem persists tests the clutch coil when it is hot. rangerj

 

[SHOmaniac1975]

IT is definately the clutch coil, if I drive at high speed it works again thanks guys. I guess I have to replace the compressor assy. now. Any removal and installation instructions for doing it on a 92 mtx?

 

[pjtoledo]

IT is definately the clutch coil, if I drive at high speed it works again thanks guys. I guess I have to replace the compressor assy. now. Any removal and installation instructions for doing it on a 92 mtx? [/QUOTE

Not that bad of a job, you do not have to remove the coolant lines. Pull the battery, unbolt the clutch disk. There is a 10mm nut in the disk, that's all that holds the disk on. The trick is holding the disk while you loosen the nut. The disk may need some gentle persuasion to slide off the compressor shaft. Then unbolt the compressor and tilt it up, you will find either 3 bolts, or a big snap ring holding the clutch bearing assembly. It's been a couple of years since I did the coil on my 92, but it is do-able.

Perry

 

[rangerj]

Once the clutch face is pryed off (wood shims between the surfaces) of the compressor shaft you will find a "snap-ring holding the pulley in place. You loosen the compressor so you can tilt it to get at the snap rings. DO NOT DISCONNECT any A/C lines. Did you test the coil by applying battery voltage to it so that it becomes a powerful electromagnet? If it fails to become a magnet it needs to be replaced.

Remove the snap-ring and the pulley, and there is another snap-ring holding the coil to the compressor. Disconnect the electrical connection to the coil. The compressor has a little "***" that lines up with the hole in the coil.

The snap-rings are beveled on one side and the beveled side should face you for correct instalation. You do not have to replace the compressor, nor discharge the system in order to replace the clutch assembly, that is the coil, clutch pulley (six rib), and clutch face. (Clutch assembly for a 10P15F Nippondenso compressor)

The face has small washers inside its shaft of different thicknesses that set the clutch gap. The gap is made smaller by using the thinner washers, or larger by using thicker washers. The gap should be about .035. Save the washers from the old clutch in case you need them to adjust the gap.

The clutch needs to be burnished and you do this by turning on the A/C for about 20 seconds at a time, for about 20 times. Read the instructions that come with the clutch assembly. They should tell you about installation and adjustments, as well as the "run-in" or burnishing of the surfaces of the clutch. rangerj