AC compressor disengages at times when in use

KCM4491

MEMBER
2004 MAZDA MPV
2.4L
4 CYL
2WD
AUTOMATIC
42,000 MILES

I have the car listed above JDM. I am the second owner of the vehicle and have been for the past couple of years. When I bought it, it only had 26,000 miles on it.
I have noticed that while idling and sometimes when driving in stop and go traffic the AC compressor will disengage and after a few minutes will reengage. This happens a lot when it the outside temperature is high. I have noticed and was thinking that maybe when the engine temperature gets a little too high that it disengages, but I have noticed that it even happens when the engine is at normal running temperature.
The AC blows out cold air when the compressor is engaged and is fine. I have also noticed that I have no problem when I have driven constantly for some time. I have read some of the other posts here and think maybe I need to charge up the AC. What do you think?

9 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

The first thing I need is the high and low side pressure readings at idle and at 1500 RPM. There are pressure switches that will shut off the compressor if they are not correct.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

When the AC is in use, do you see water leak from the evaporator to the ground?

Roy

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Sunday, August 4th, 2019 AT 8:17 AM

KCM4491

MEMBER
5 POSTS

Roy,

Thank you for your reply. I have noticed some water on the ground. As for the reading. I need to get a gauge and then let you know.

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Sunday, August 4th, 2019 AT 5:23 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, sounds good.

I need both the high and low side of the AC system.

Roy

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Sunday, August 4th, 2019 AT 5:35 PM

KCM4491

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5 POSTS

Roy,

Sorry for taking so long to reply. I had to order a gauge and it took forever to get here. I have taken some photos of the readings on the gauge at idle (700 rpm) and at 1500 rpm. And just in case I am also including one with the AC off. I was not able to get a reading when the clutch disengages while it was running. However, when it occurred on a recent drive, I took a picture of the engine temperature if this helps. Also when there are no issues with the system it blows out very cold air.

Regards,

Kimball

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Thursday, August 15th, 2019 AT 8:48 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

If the third picture is with it running, that is why it is not working or cutting out. The low-pressure switch will cut out the compressor at 20 lbs and below.

What about the high side pressure? I told you I needed both sides?

Roy

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Saturday, August 17th, 2019 AT 4:03 PM

KCM4491

MEMBER
5 POSTS

Roy,

I was finally able to get the measurements. I have attached the pictures. They are in order.

1) Engine off.
2) Idle.
3) 1,500 RPM.

Regards,

Kimball

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Saturday, September 7th, 2019 AT 9:41 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, I would start by removing the Freon and evacuating and charging the system with the correct amount of Freon.

From the readings you provided, either it is low in Freon or the expansion valve is bad.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Roy

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Sunday, September 8th, 2019 AT 4:44 AM

KCM4491