[steves7839]

Recently got warm 65 degree dash air from our 95 Odyssey 169k miles, first owner. My wife tells me the engine shuddered when the dash air stopped being cool.
The AC only needed service once before. I had my mechanic check level and charge in 1998 or so. It has been working fine all these years until mid-August.

I bought a low side charge kit with pressure gauge. After adding about 16 oz, the compressor began cycling off and on. The idle RPM dropped to about half of normal when the AC cycled on, then recovered. And the system went from cooling to blowing 65 degree air.

I think the system is near fully charged. The low pressure is 65, the AC-off system pressure is 75. The system cools well for a few minutes, then the idle slows down and the clutch (and condensor fan) disengages. When driving, the engine shudders as if slowing down periodically when the cooling stops. All fans work.
There is no icing on the low side lines and the high side lines are hot to touch but not burning hot.

The compressor is not making any unusual noises. Is the symptom set consistent with a failing compressor?

 

[William Wiles]

Was the AC working before you charged it? Sounds to me like you have it overcharged. Pressure with the compressure not running means nothing. You have to check it on the low side with the compressure engaged.

 

[steves7839]

Thanks for your post. I have edited OP to clarify your questions.

 

[steves7839]

AC compressor short cycle update

I got a pair of pro gauges to test with. With front and rear AC on high, the pressures read LOW 45 HIGH 240 at ambient of 90F. Temperature at the dash reads 52F, good by any standard.

Then I drove the car a few miles. At slow neighborhood speed, the compressor resumed short-cycling and the dash temp rose to 65F. Neither the fan relay, compressor relay or compressor connector at the fan shroud seem sensitive to vibration or loose connection.

I believe the system is fully charged, but something such as a pressure switch is going open.