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A/C Compressor Cycling On & Off ...Seems Random

tommywommy on Fri August 21, 2015 10:50 PM User is offline

Year: 2006
Make: Toyota
Model: Sienna
Engine Size: 6cyl
Refrigerant Type: R134a
Ambient Temp: 90ish
Pressure Low: 32-44
Pressure High: 190-210
Country of Origin: United States

Hello Everyone!,
I'm new to this forum. Thanks in advance for any help you can offer! It is much appreciated. My vehicle's A/C blows cold for about 20 minutes (compressor on), then will get warm (compressor cycles off) for anywhere between 3 & 10 minutes. Then the compressor will come back on with cold air again for 3-5 minutes....then warm....repeat repeat repeat.

Here is the gauge reading for the first 15 minutes when everything seems to be working.


Then.....when the compressor disengages the gauges read this. The low side slowly rose from about 58 and topped out at 68 before the compressor re-engaged.


Then the compressor turned back on and the gauges showed this for a few minutes before the compressor again disengaged.


I am a classic shade tree mechanic...but have little experience with A/C so I apologize if my questions are silly or don't make sense. Thanks again for any help you can give!

Edited: Fri August 21, 2015 at 10:56 PM by tommywommy

mk378 on Sat August 22, 2015 8:43 AM User is offline

Often this is just the clutch gap making the compressor reluctant to engage when it is hot. You can check this by waiting until it stops cooling, then tap the clutch plate with a suitable tool. If that makes it pull in and start cooling, you need to take some of the shim washers out to reduce the gap.

tommywommy on Sat August 22, 2015 1:08 PM User is offline

Okay, I'll see if that helps. Thanks for the suggestion!

tommywommy on Thu August 27, 2015 10:41 AM User is offline

I tried bumping and slightly tapping the compressor plate but I couldn't get it to engage. I'm still stumped.

bohica2xo on Sat September 19, 2015 3:24 PM User is offline

That vehicle has a block type TXV for the front A/C. If it has rear A/C it has a standard bulb type TXV at the rear.

Cycling will be controlled by a temperature switch & sensor.

I would check or replace the compressor relay. Random operation from a tired relay is a common problem.

"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Cesarchavez on Tue September 22, 2015 10:29 AM User is offline

Yes, you are right @mk378 , i was facing this type problem. The auto mechanic told me the problem is in car clutch. And they fix that and solve my problem. Thanks to Deltaautocare. I satisfy with the service. Thanks a lot.

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