04 gmc yukon

[Kaysie Rainwater]

What is the recommended air conditioner pressure for 04 gmc yukon?

[Jsdirt]

Whatever pressure it's at when the system is cooling to the best of its ability.

 

There's no "recommended pressure" on any A/C system. That changes with ambient temperature, and can change pretty wildly with wide temp swings. Your gauges are just to alert you of problems.

 

High side too high (300+ psi or higher) on a 70° day indicates the condenser isn't getting adequate airflow, if the low side is at a reasonable pressure.  Could be a bad fan clutch, slipping belt, failing electric fan if equipped, debris between condenser and radiator, etc.. On a 100° day, 300 psi might be normal. 

 

If both low and high sides are high and there's little to no cooling, there could be air or other non-condensables in the system.

 

Rule of thumb that I always shot for was to get the outlet of the evaporator just slightly cooler than the inlet. That means you've got a little liquid refrigerant in reserve in the accumulator, and if the system is leak free, you'll have many years of service.

 

And ALWAYS charge into a vacuum for best results. Unless you're topping off ... which is frowned upon in the professional world. In that case you have to purge the lines with refrigerant (*illegal!*) to remove the air.

 

Bottom line is you need a LEAK FREE system before doing any service. Got to find and fix ALL leaks FIRST.

 

STEER CLEAR OF SEALER!! And beware of cans containing oil charge. If you already have the correct amount of oil, then charge the system with a can containing oil, you've just killed the efficiency of the system. The more oil over the amount required, the worse the system will perform, up to not cooling at all ... or worst case scenario, a catastrophic compressor failure which will then render every single component of your A/C system trash.

[txab]

13 hours ago, Jsdirt said:

Whatever pressure it's at when the system is cooling to the best of its ability.

 

There's no "recommended pressure" on any A/C system. That changes with ambient temperature, and can change pretty wildly with wide temp swings. Your gauges are just to alert you of problems.

 

High side too high (300+ psi or higher) on a 70° day indicates the condenser isn't getting adequate airflow, if the low side is at a reasonable pressure.  Could be a bad fan clutch, slipping belt, failing electric fan if equipped, debris between condenser and radiator, etc.. On a 100° day, 300 psi might be normal. 

 

If both low and high sides are high and there's little to no cooling, there could be air or other non-condensables in the system.

 

Rule of thumb that I always shot for was to get the outlet of the evaporator just slightly cooler than the inlet. That means you've got a little liquid refrigerant in reserve in the accumulator, and if the system is leak free, you'll have many years of service.

 

And ALWAYS charge into a vacuum for best results. Unless you're topping off ... which is frowned upon in the professional world. In that case you have to purge the lines with refrigerant (*illegal!*) to remove the air.

 

Bottom line is you need a LEAK FREE system before doing any service. Got to find and fix ALL leaks FIRST.

 

STEER CLEAR OF SEALER!! And beware of cans containing oil charge. If you already have the correct amount of oil, then charge the system with a can containing oil, you've just killed the efficiency of the system. The more oil over the amount required, the worse the system will perform, up to not cooling at all ... or worst case scenario, a catastrophic compressor failure which will then render every single component of your A/C system trash.

^^^^ All excellent info