Year: 1993
Make: Lexus
Model: SC400
Hi:
I know the a/c system probably has a leak, but I'm in denial b/c I spent hours fixing it this week. Besides a leak in the system, would something else cause the disparity in the readings? The same gauges were used.
Oh, when I checked today, I only attached the Low Side hose. Would connecting the High Side as well make a difference in the readings?
Thanks.
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'98 328i
Charge the system!!!
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Tim:
Are you saying the system should be good to go even though it dropped by 1 Hg? Don't want to waste the R12!
Or should I charge with 134a and see if it holds?
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'98 328i
A simple change in temperture, amoung other things, could cause that after 48 hours.. I agree, pull it down again and charge the system....Let us know what happens...
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
You got a tiny bit of air in it when you re-connected the hoses/fittings, analogous to the brief spit of refrigerant that would leak out had the system contained refrigerant. So I agree with the others, don't be so anal about this: pull good vacuum, and charge with proper amount of refrigerant. Even if you had NOT disconnected and reconnected the hoses, such a small change would be insignificant.
When we check to see if a system is holding a vacuum it is like for 10 minutes. The variables in your 48 hours test are too many to list. My suggestion is charge it and leak check it with an electronic or UV detection device.
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I wouldn't worry about that at all!
For my car (Saturn), the Factory service manual specifies that anything less than 1" drop within 5 minutes is acceptable.
I usually leave my gauges hooked up after pump down overnight. If the system is tight, I've never seen a drop in reading. IMO a drop of 1" in 5 minutes would indicate a pretty good leak somewhere.
AirLift airbags spring assists expected weak me to roll up their bags and jammed them in a tiny 2" diameter hole by hand. Called them said leave them out in the sun, said I already put them in my chamber and heated them to 165*F, still no luck. So I installed brand new Scharder tire valves, jury rigged a tire chuck to my vacuum pump and really sucked out the air. Clever? But as soon as I removed the chuck air started leaking back into this bags, vacuum was pulling the Scharder valve open, had to quickly install the cap.
This is a flexible bag and not a hard device like an AC system, point is that AC systems are not designed to hold a vacuum, but to hold pressure, compressor seals are notorious for pulling in and sucking air. With your gauges installed, barometric pressure variations are key in your actual vacuum reading.
You are not the only one cautious and no longer dealing with a 75 cent can of R-12. To be cautious, would connect the blue line to the pump, yellow to a closed off can, red to the high side. Open the low side, draw a deep vacuum to the open high side and also way down to the can's valve, close off the low side and dump just one can in. Remove the gauges, then check for leaks, only sacrificing one can and with pressure, better to have a little R-12 leak out than air being sucked back in, so can finish off the charge from there, purging with each added can. Well, that is why I like the tanks, saves all that purging.
But hopefully, all is well that ends well.
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