Automotive Air Conditioning Information Forum (Archives)

PaulH on Mon August 17, 2015 11:26 AM

Year: 1997
Make: Jeep
Model: Grand Cherokee
Engine Size: 5.2
Refrigerant Type: 134a
Ambient Temp: 100
Pressure Low: 40
Pressure High: 250
Country of Origin: United States

Over the last couple weeks, the A/C in my 97 Grand Cherokee began to lose its cold. Now, over this past weekend, it got to the point that it doesn't cool enough to be usable, even at highway speed.
The pressures at idle speed and 100F ambient temp are 250 on the high side, and 40 on the low. Compressor operating continuously. Seemingly normal. The tube going into the evaporator is cold, but the tube coming out is not.
When the engine speed is raised, the compressor cycles off/on every few seconds and the low side pressure fluctuates widely, up to about 90 and down to about 20 psi. High side also fluctuates, maybe 200-240 or so.
The compressor is clearly noisier than it used to be.
Note the factory system was replaced about 80,000 miles ago. The vehicle has 283,000 miles on it.

bohica2xo on Mon August 17, 2015 1:02 PM

You have a leak. The system is nearly empty.

If there is dye in the system you may see where the refrigerant went. In any case, find the leak, fix the leak & recharge by weight.

.

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"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.

PaulH on Mon August 17, 2015 1:34 PM

Thanks. I will check for dye. I have a UV light. Just haven't had a chance to do so yet.
I'm surprised the pressure is as high as it is if it were very low on refrigerant.