AMC Eagle Den Forum

The Shop => Under the Hood & HVAC => Topic started by: marty on March 15, 2016, 11:39:26 PM

Title: AC press readings and temp from vents
Post by: marty on March 15, 2016, 11:39:26 PM
Anyone know what the low and high press readings should be w R12 in the system (I have R12 compatible HC12)?  Also, what should the temp be from the vents (I'm getting about 52 F w my IR temp sensor).
Title: Re: AC press readings and temp from vents
Post by: eaglebeek on March 16, 2016, 07:57:23 AM
There are many factors that affect pressures...outside air temperature, inside-the-car temperature, engine speed, etc....that it would be difficult to say exactly what pressures are correct. As a general rule of thumb the high pressure side should be 7-10 times low side pressure. Example: if low side pressure is 30psi high side pressure should be 210-300psi.

IR thermometers are difficult for gauging air temperature. Instead they try to gauge the temperature of surrounding objects. Using a mechanical thermometer  held at the center duct you should get 42 degrees or less with the car closed up and the engine running at a fast idle...somewhere around 1,000rpm.
Title: Re: AC press readings and temp from vents
Post by: marty on March 16, 2016, 04:17:46 PM
Hmm, will try the regular thermometer.  I was running about 30 psi on the low side and about 150psi on the high side, outside air temp in the low 80's.
Title: Re: AC press readings and temp from vents
Post by: rmick on March 16, 2016, 11:30:49 PM
Those pressures are about right for R12. You should also get about a 15-20 degree drop in temperature across the evaporator. the inlet side as apposed the the outlet temperature
Title: Re: AC press readings and temp from vents
Post by: JayRamb on March 17, 2016, 09:38:01 PM
Where can one find an R-12 valve to the can to the AC compressor?!

I FOUND ONE ON EBAY!!! YAY!!
Title: Re: AC press readings and temp from vents
Post by: macdude443 on March 24, 2016, 02:54:39 PM
When I had my R12 recharged last summer, with true R12, the shop read 39* at the vents on a 75* day.
Title: Re: AC press readings and temp from vents
Post by: JayRamb on March 24, 2016, 03:03:50 PM
Found one on eBay!!! Yay!!