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SUPRYZE
SUPRYZE, Technician/Shop Foreman
Category: Car
Satisfied Customers: 2158
Experience:  GM & Saab Certified, ASE Master Technician
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We have pressures of 30psI on the low side and 40 PSI..compressor

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A/c has static pressure about 90lbs. When system runs we have pressures of 30psI on the low side and 40 PSI on the high side. Suction side sweats back to compressor high side has no heat in line?? Please advise

SUPRYZE :

Hello and welcome to Just Answer!

SUPRYZE :

Based on the pressure readings, I suspect that you have a low refrigerant charge. Your static pressure is about right (depending on what the outside air temp is).

SUPRYZE :

However, you can charge a system and reach the desired static pressure, before the system is truly "full".

SUPRYZE :

Your low side pressures can make it hard to diagnose, because of the type of A/C compressor used on these vehicles. The compressor is a varible displacement type, which adapt to low charge situations.

SUPRYZE :

The high side pressure, however, indicates there isn't enough refrigerant. I would reccomend having the system recovered and the quantity removed measured.

SUPRYZE :

If no visible leaks can be found during the recovering process, it would be a good time to add system dye before recharging.

SUPRYZE :

This way, if it does leak down, it will be easier to find a leak.

Customer:

The compressor seems to have a steady ticking or tapping sound that comes and goes is that the compressor compensating for low charge?

SUPRYZE :

Its possible. Sometimes when refrigerant leaks out, oil leaks out with it. It could be low on both refrigerant and oil.

SUPRYZE :

I would first see how much is in the system. It sounds like its low. If it turns out to be full, then you most likely have a faulty compressor.

SUPRYZE :

Your pressures indicate that it should be low, but the Variable Displacement compressor can cause funky readings.

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