Replaced the orifice tube on the GN this morning because the a/c was not getting cold. Recovered the R12,blew the system out & did pull a vacuum on the system for about 35 mins. at 30" Hg. After the addition of the R12 back into the system, the pressures are as follows: 35 lo & 225 hi side. Then after around 5 mins. pressures were around 38 lo & 275 hi- holding. Seems that the line on the orifice side going to the inside of the car (evaporator) is very cold but out the evaporator into the accumulator it is only cool (not enough for condensation to build up). Question is -with the pressures at 38 lo & 275 hi- the car is shut off and the equalization of the pressures on the gauges happens within 5-10 seconds. Is this normal or is the A/C compressor going bad? Could the water valve be leaking by? Help. South Texas Heat!
A/C Pressures
- Thread starter 1QUIK6
- Start date
Hmm, I'd say 30 secs is more the norm on an orifice system, but the fact a) it equalizes, b) both high and low are both a little high makes me thing its merely a little overcharged.
I neglected to look where you're from so I dont know what ambient is/was. You could also have some moisture in the system, but I dont know. I'd take a little out and see what it does first
<edit> I see youre from TX, and will assume its hot down there. I stick to my first opinion that its overcharged
I neglected to look where you're from so I dont know what ambient is/was. You could also have some moisture in the system, but I dont know. I'd take a little out and see what it does first
<edit> I see youre from TX, and will assume its hot down there. I stick to my first opinion that its overcharged
I have let out a little R12 (4 sec. interval 5 times waiting awhile inbetween intervals) & seems to have cooled the lines a little more, but the A/C compressor is kicking off and on at about every 12sec. Don't know if this is the norm.? Should I continue to let out a little more?
Assuming a Tx day, say 85, decent humidity, cooling fan on high, I'd expect to see highs in the 200 area and lows in the 32 area. Cycling is OK if its not rapid, and the high sides goes to that 200ish mark. Theres a relationship between low side press and evap temp. It is designed to cycle the compressor to keep the evaporator from freezing, so its very possible to have the system cycle. Shoot for a 30* drop from ambient. Anything more than that is gravy.
So why isn't- the return line from the evaporator, the accumulator and the line to the compressor not getting cold? Could it still be overcharged? "Shoot for a 30* drop from ambient" Does that mean the low side should be (outside temp-30)= low side press?
Thanks In Advance
Thanks In Advance
salvageV6
Daily Driver
- Joined
- May 25, 2001
Undercharged, I like to see 1-2 cycles per minute, manual says 6 is okay.
Just my .02.
Pipes should be even temp. without freezing solid of course.
I'd be adding R12 and watching pressures not letting that good stuff out.
Just guessing long distance of course.
Just my .02.
Pipes should be even temp. without freezing solid of course.
I'd be adding R12 and watching pressures not letting that good stuff out.
Just guessing long distance of course.
- Joined
- May 26, 2001
If you have a original compressor, it is probably at the end of its useful life.
At 35-38 psi it is not doing the job of pumping down. When I see a system with symptoms like yours, a new compressor solves the problem. After installing a new Delco unit, low pressure will come down to ~25 psi at 100+ deg ambient.
[Jim, thanks for sending Dom to me, his car is here now!]
At 35-38 psi it is not doing the job of pumping down. When I see a system with symptoms like yours, a new compressor solves the problem. After installing a new Delco unit, low pressure will come down to ~25 psi at 100+ deg ambient.
[Jim, thanks for sending Dom to me, his car is here now!]
first turbo
Member
- Joined
- Dec 13, 2002
YOU MAY HAVE AIR IN THE SYSTEM, NO LEAKS IS A MUST, YOU COULD SHOW A GOOD VACUUM ON A GAUGE AND STILL HAVE A VERY SMALL LEAK. THINK ABOUT IT WHEN YOUR SYSTEM IS A VACUUM IF THER IS A LEAK YOU ARE BRING IN AIR( WHICH IS A NON CONDENSIBLE) THIS WILL NOT SHOW ON A GAUGE,CAN ONLY BE SEEN ON A MICRON METER. CHECK YOUR WORK FOR LEAKS EVACUATE AND RECHAGE BY WEIGHING THE CHARGE IN TO THE FACTORY SPEC.
