Mechanics

PRESSURE READINGS

2001 Pontiac Montana

Air Conditioning problem
2001 Pontiac Montana 6 cyl Front Wheel Drive Automatic 220000 miles

I have hooked up a/c guages to lo and hi connections and I get a correct static pressure on both with car off ( mid 70's psi @ 80 ish degrees F ).
When car started and running for about a minute I press a/c button and here the ac kick in but only get hot air. The guages read lo - 32psi and hi - 100psi. All the a/c troubleshooting tips I have read has no information for these readings. They have lo lo - hi lo
lo high - hi high etc. With possible causes. I assume the compressor is kicked in because the lo and hi pressure guages change when the a/c button is depressed. Any help would be appreciated

Bob G.
Avatar
Rcg@rogers.com
July 9, 2010.



What is vent temp? Have you added 134A? System been opened? Repairs?

Docfixit
Jul 9, 2010.
I have owned the vehicle since new. About 4 years ago a new compressor was installed by the dealer and it has worked fine till this year. The outdoor temp was 90 deg f. The vent temp was 100 deg f.
The first thing I did was buy a REDTEK charge kit which came with 2 cans of r12 compatible freon and a low pressure guage. The low pressure guage read slightly low so I added some freon. I then started the vehicle and obtained a reading in the low 30's but still got no cool air. I then hooked up a high pressure guage and got the readings as I originally stated.

Tiny
Rcg@rogers.com
Jul 11, 2010.
Your system is filled with 134A you sure you put R12 compatable? If yes not good. Static reading should have been 90-100 and running Low 35 high 270-300 so system needed charging. But not with R12 compatable

Docfixit
Jul 11, 2010.