Air conditioner question

[aggieblazer07]

I've heard that you could check the R-134a level by taking the temperature at the air conditioner vent. Does anyone know what temperature it should be, or any other way to check it without specialty tools?

[fbronco86]

normally they blow at like 40ish F

[mudtoy67]

It varies depending on the vehicle. I've got a set of 134 gauges if you want to check it sometime next week.

[aggieblazer07]

It's on my mom's 99 suburban back in Dilley, so there wouldn't be anyway for me to bring it by

[mudtoy67]

If you can get a hold of a temp probe, you can check the level at the evaporator. Touch the probe to the inlet/outlet lines on the evaporator, as close to where they pass through firewall as possible (as close to the evaporator as possible). Run the A/C with the windows down, Max A/C, highest fan speed. After it has been running for 5-10 mins (so the system can stabilize), check the temps on the lines, they should be within 5 degrees of each other. If the outlet is more than 5 degrees warmer than the inlet, the system is undercharged. If the outlet is more than 5 degrees cooler than the inlet, the system is overcharged. If it is undercharged, and you decide to add, only add a little at a time, wait 5-10 mins again, and check the temps again.

[fbronco86]

It's on my mom's 99 suburban back in Dilley, so there wouldn't be anyway for me to bring it by

I think the compressors on those trucks tend to crack in the parting line of the casting from be improperly torqued down to the bracket. Look right in the middle of the compressor and see if you see any oil around it. I did this a few times on my dads truck until I went to the dealer to get a real compressor and the mechanic there told me this.