lobo411
Well-Known Member
- Joined
- September 14, 2011
- Messages
- 925
- Reaction score
- 61
- Year, Model & Trim Level
- 1996 Explorer 4.0 OHV
Hi all,
96 4.0 OHV ... No prior history of any a/c issues. At the beginning of the summer I refilled my mom's Taurus w/ 134a (she has a definite slow leak...going from fully charged to 10 psi in 6 months) using my dad's old R12 gauge set, which I converted to R134a hoses/connectors.
At the same time, I decided to put the gauges on my Explorer. The a/c worked fine, but the cold wasn't terribly cold. I got about 24 PSI on MAX at 80 degrees, so I decided to add a little. It wasn't charging very quickly, if at all, so I gave up. However, the a/c did get colder.
Fast forward 3 months to this week. One morning, after the vehicle had been driven on the highway w/o a/c and parked for 2 hrs, then started again, then had the a/c turned on, I got warm air from the vents. Eventually the a/c kicked in and I got good, cold air. It took about 5 mins for the a/c to kick in, so there's a definite issue.
Today it happened again...warm air from the vents after being parked for 2 hrs, then the a/c kicked in.
I put the low side gauge on and got around 30 psi at 85-90 degrees. I turned off the car and went inside to google what the reading should be, and I forgot that I had attached a can of R134a. For about 10 mins, while the car was at idle with the a/c on and after I shut it off to go inside, the car was there with the can tap open.
When I returned and started the car, the a/c was exhibiting unusual behavior. Once the compressor was going on MAX, the low side would go to 50 psi, then creep down to 35 PSI, I'd hear a PSSST--CLICK sound, and the idle would momentarily become labored. The a/c clutch disengaged and the psi creeped back up to 50 psi, and the cycle started again.
This is the reverse of the normal a/c cycling pattern. Unfortunately, I was unable to connect the quick disconnect to the high-side (just wouldn't latch on), so I have no idea what was going on there.
That's when I noticed the open can of R134a. I guessed that I had inadvertently overcharged the system, so while I wouldn't vent it to the atmosphere b/c that would be illegal, I wished upon a star and now the system seems to be running fine at 40 PSI low side @ 90 degrees.
So...questions:
1. Any thoughts/ideas on the original problem, which is the a/c not engaging after sitting hot for 2 hrs? I haven't been able to manually watch the compressor to see what happens under those conditions, so that will be my next test.
2. Any possible damage from the overcharge and wishing upon a star process? I was thinking that atmospheric pressure is about 20 psi, and the system was pressurized to 40-50 psi when the fairy did its magic, so there's no danger of atmospheric air getting in until the system pressure is lower than the atmospheric pressure, right?
Thanks!
96 4.0 OHV ... No prior history of any a/c issues. At the beginning of the summer I refilled my mom's Taurus w/ 134a (she has a definite slow leak...going from fully charged to 10 psi in 6 months) using my dad's old R12 gauge set, which I converted to R134a hoses/connectors.
At the same time, I decided to put the gauges on my Explorer. The a/c worked fine, but the cold wasn't terribly cold. I got about 24 PSI on MAX at 80 degrees, so I decided to add a little. It wasn't charging very quickly, if at all, so I gave up. However, the a/c did get colder.
Fast forward 3 months to this week. One morning, after the vehicle had been driven on the highway w/o a/c and parked for 2 hrs, then started again, then had the a/c turned on, I got warm air from the vents. Eventually the a/c kicked in and I got good, cold air. It took about 5 mins for the a/c to kick in, so there's a definite issue.
Today it happened again...warm air from the vents after being parked for 2 hrs, then the a/c kicked in.
I put the low side gauge on and got around 30 psi at 85-90 degrees. I turned off the car and went inside to google what the reading should be, and I forgot that I had attached a can of R134a. For about 10 mins, while the car was at idle with the a/c on and after I shut it off to go inside, the car was there with the can tap open.
When I returned and started the car, the a/c was exhibiting unusual behavior. Once the compressor was going on MAX, the low side would go to 50 psi, then creep down to 35 PSI, I'd hear a PSSST--CLICK sound, and the idle would momentarily become labored. The a/c clutch disengaged and the psi creeped back up to 50 psi, and the cycle started again.
This is the reverse of the normal a/c cycling pattern. Unfortunately, I was unable to connect the quick disconnect to the high-side (just wouldn't latch on), so I have no idea what was going on there.
That's when I noticed the open can of R134a. I guessed that I had inadvertently overcharged the system, so while I wouldn't vent it to the atmosphere b/c that would be illegal, I wished upon a star and now the system seems to be running fine at 40 PSI low side @ 90 degrees.
So...questions:
1. Any thoughts/ideas on the original problem, which is the a/c not engaging after sitting hot for 2 hrs? I haven't been able to manually watch the compressor to see what happens under those conditions, so that will be my next test.
2. Any possible damage from the overcharge and wishing upon a star process? I was thinking that atmospheric pressure is about 20 psi, and the system was pressurized to 40-50 psi when the fairy did its magic, so there's no danger of atmospheric air getting in until the system pressure is lower than the atmospheric pressure, right?
Thanks!
