Problem with A/C compressor randomly not engaging

[Marcozi]

Did you scan the climate control module for codes? In most modern cars the module receives sensor inputs (i.e., refrigerant pressure, etc.) and controls the compressor clutch engagement.

 

[inquirer]

Did you scan the climate control module for codes? In most modern cars the module receives sensor inputs (i.e., refrigerant pressure, etc.) and controls the compressor clutch engagement.

No, I haven't. Most probably the official scan tool is going to be needed for that purpose. But the air gap is obviously well out of specs so it anyway needs adjustment.

 

[vwmaniaman]

You can try removing the front plate and removing one thin shim and see if it acts the same. Or you can take out several but make sure when you put it back together that you can freely turn the front with the motor off and no scraping sound.

 

[inquirer]

You can try removing the front plate and removing one thin shim and see if it acts the same. Or you can take out several but make sure when you put it back together that you can freely turn the front with the motor off and no scraping sound.

I'm going to use a feeler gauge and adjust the clearance at the tightest allowed specification.

 

[inquirer]

I had the chance to use a feeler gauge today. I measured the air gap with the engine hot, if that makes any difference.

The 0.7 mm blade (0.02756 inches) is the thickest that fits in the gap. The 0.75mm (0.02953 inches) blade did not fit in. The accepted range for the gap according to Mitsubishi is 0.25 - 0.5 mm (0.010 - 0.020 inches).

So the air gap is wider about 0.2 to 0.25 mm (0.00787 to 0.00984 inches) than the maximum allowed spec. Is this difference possible to cause the problem or should I start the troubleshooting from other possible causes?

 

[vwmaniaman]

I had the chance to use a feeler gauge today. I measured the air gap with the engine hot, if that makes any difference.

The 0.7 mm blade (0.02756 inches) is the thickest that fits in the gap. The 0.75mm (0.02953 inches) blade did not fit in. The accepted range for the gap according to Mitsubishi is 0.25 - 0.5 mm (0.010 - 0.020 inches).

So the air gap is wider about 0.2 to 0.25 mm (0.00787 to 0.00984 inches) than the maximum allowed spec. Is this difference possible to cause the problem or should I start the troubleshooting from other possible causes?

Sounds like you found the problem so remove some shims and try it. I bet it works now.

 

[D60]

I had the chance to use a feeler gauge today. I measured the air gap with the engine hot, if that makes any difference.

The 0.7 mm blade (0.02756 inches) is the thickest that fits in the gap. The 0.75mm (0.02953 inches) blade did not fit in. The accepted range for the gap according to Mitsubishi is 0.25 - 0.5 mm (0.010 - 0.020 inches).

So the air gap is wider about 0.2 to 0.25 mm (0.00787 to 0.00984 inches) than the maximum allowed spec. Is this difference possible to cause the problem or should I start the troubleshooting from other possible causes?

I can't remember now -- did you jumper it and try to knock it in to see if it engages? Or even see if it "magnetizes" when jumpered?

If you can prove to yourself some magnetic action occurs when triggered, yeah, your air gap is likely a problem. If not, then the problem is elsewhere

 

[inquirer]

I can't remember now -- did you jumper it and try to knock it in to see if it engages? Or even see if it "magnetizes" when jumpered?

If you can prove to yourself some magnetic action occurs when triggered, yeah, your air gap is likely a problem. If not, then the problem is elsewhere

No, I haven't tried anything else. I just measured the air gap. If the measurement is valid with the engine hot, then the gap is wider than the max allowed spec, as I mentioned in my previous post. (I gave the exact numbers.)

The problem occurs relatively rarely, I would say about 5 times a month, so I don't have many chances for tests as the frequency of the problem remains low.

 

[D60]

No, I haven't tried anything else. I just measured the air gap. If the measurement is valid with the engine hot, then the gap is wider than the max allowed spec, as I mentioned in my previous post. (I gave the exact numbers.)

The problem occurs relatively rarely, I would say about 5 times a month, so I don't have many chances for tests as the frequency of the problem remains low.

Ok then sure, adjust the gap. You are almost 50% out of max spec after all

 

[inquirer]

Ok then sure, adjust the gap. You are almost 50% out of max spec after all

Yeah, you are right about that. I wonder though if the specs are really marginally defined. If not and they leave a safety room, then maybe adjusting the air gap won't fix the problem.

At that point I guess I'll better adjust the gap anyway aiming for the 0.25 mm (0.00984 inches) value. If that does not fix the issue then I will have to investigate other possibilities.

 

[SHOZ]

My feeler gauge set has .010" as brass. Perfect for coils on a mower and I bet magnetic clutches.

That being said if you are removing the shim and not replacing, there is probably little need to measure.

 

[inquirer]

My feeler gauge set has .010" as brass. Perfect for coils on a mower and I bet magnetic clutches.

That being said if you are removing the shim and not replacing, there is probably little need to measure.

Maybe you are right, but measuring the gap is so easy, that there is no reason to skip the measurement.

 

[inquirer]

After one year, a few days ago when the temperature started to climb, I finally had the shim removed. So far the compressor has not encountered any missed engagements, so almost certainly the air gap was the issue.