A/C not cooling enough after compressor kit replacement (2006 Mazda3)

[mizzleman]

Hello All,
New member on this site and I am hoping you can give me some help on a perplexing problem. I've worked on cars for decades but am a little new to A/C work. A while ago, my A/C compressor locked up and I replaced it with a UAC kit (compressor, condenser, drier and expansion valve). I have the Mazda Service Manual and I replaced the components as dictated by the procedures in the manual. A/C lines were flushed and blown dry, new seals installed, AC oil came in the correct amount in the new compressor, and system evacuated to 28mmHG and charged to 24PSI Low, 250PSI High (near 100F degree temps) at 1500 RPM. As far as I can tell the 22PSI is about 95F degrees per the manual and I was definitely hotter than that. Hard to read the graph in the manual, but graph goes higher than 22 at near 100F degree temps.

Problem is, I can only get about 70F degrees at the AC ventilation ports. All temps, etc. taken while car is in the driveway with the radiator fan running.
Driving it, I can get the AC vent temp down to about 65, but no more.

I am thinking that one of the new components is faulty and leaning towards either the compressor or expansion valve.
Anyone experience something like this or have an idea of where to look for the issue?
Thanks in advance.
Car is 2006 Mazda 3 S A/T

 

[Mazdiod2]

Problem is, I can only get about 70F degrees at the AC ventilation ports. All temps, etc. taken while car is in the driveway with the radiator fan running.
Driving it, I can get the AC vent temp down to about 65, but no more.

what is the outside temp ?

 

[mizzleman]

Outside temp is 98-100F,
Also car is running at 1500RPM, 24PSI low side, 250PSI high side
Graph in Service Manual is hard to read, so assume pressures are in range at the Max at that temperature

 

[jbsx]

Did the manual not say to charge the system to a certain amount of refrigerant? I think 16 to 18 ozs rather than try to set the system to a pressure/temperature reading.
Sounds like you are undercharged.

 

[mizzleman]

Unfortunately, I do not have any way to measure the charge itself....no scale or recovery type of machine. I did this work over a year ago and it's now bugging me to he point I'm looking to improve performance.
But adding any refrigerant pushes the pressures out of the range Max for both Low and High side pressures.
However, I could go the other way and maybe the system is overcharged and lessen the pressures to their minimum values.
All else, I'll need to find someone to do a recovery and recharge of the refrigerant to measure the charge level.

 

[jbsx]

I think you are way undercharged. You should either have someone remove and recharge the system to proper weight. This would be the easiest method (probably between $100 and $200 dollars)
Low side PSI at 100 degreesF should also be much higher than 24psi. Around 50psi but I don't know what chart you were looking at or what it says.

 

[mizzleman]

Service Manual shows Low Side MAX pressure 22PSI, High side MAX 242 at 1500 RPM (not idle) at 95F degree ambient temperature. It's been pushing 100F when I am checking the system.

This is the paper Factory Service Manual, not a Chilton, Haynes, or some knockoff service manual CD.

When I get a chance, I'll have the system recovered and recharged and see where the performance is.

 

[Bruisermac]

Service Manual shows Low Side MAX pressure 22PSI, High side MAX 242 at 1500 RPM (not idle) at 95F degree ambient temperature. It's been pushing 100F when I am checking the system.

This is the paper Factory Service Manual, not a Chilton, Haynes, or some knockoff service manual CD.

When I get a chance, I'll have the system recovered and recharged and see where the performance is.

Use any weigh scale to measure the charge. At 250 psi for high side way too high. I suspect overcharge.