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Registered
Join Date: Nov 2000
Location: Dallas
Posts: 3,575
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Checking Freon Level
I suspected my 88 was low on R12 so decided to add some but I have a question about the site glass. Before I added anything it appeared to be clear w/ ac on and running at 2k rpms and the small ball stayed at the bottom. I hooked up the freon and had my gf keep it at 2k rpms. The freon can got VERY cold and the a/c is now running about 15 degrees cooler at the vent. (Previously saw 70 w/ ambient temp low 90's, now seeing upper 50s at vent, same amb. temp) The site glass looks exactly the same...totally clear and little bead/ball at bottom. Is it possibly still low? About how long should a system take to take in a can of R12? I ran it about 5 minutes and the bottom 2" of the freon can was ICE cold with frozen condensation on outside.
Thanks,
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Buck '88 Coupe, '87 Cab, '88 535i sold, '19 GLC 300 DD Warren Hall, gone but not forgotten |
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06-28-2003, 02:52 PM
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Join Date: Jan 2003
Location: SF Bay Area
Posts: 125
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How big was the can of R12? I believe your car holds about 40oz total.
...Bruce |
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06-28-2003, 03:38 PM
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Location: Dallas
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It was a 12 oz can but the system was far from being empty. I'm just curious as to what I should have seen on the site glass and if maybe I should have kept the can on the car longer. It's sealed up so I can add more freon if that's what's needed.
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Buck '88 Coupe, '87 Cab, '88 535i sold, '19 GLC 300 DD Warren Hall, gone but not forgotten |
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06-28-2003, 03:47 PM
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Registered
Join Date: Jan 2003
Location: SF Bay Area
Posts: 125
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As far as I know you should see the ball floating in the middle of the sight glass. You can also get a pressure gauge and check the system pressure at the compressor to get a better idea of how much freon you have.
...Bruce |
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06-28-2003, 04:05 PM
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I've never trusted the "sight glass" on any car, much better to check pressures or, even better yet, monitor temp. at the vent; add coolant unitil you see temperatures in the mid to high 40's at the center vent with the fan at 1/2 speed, that's probably as good as you'll ever get with the stock system. BTW, if the system is close to fully charged it can take 10-15 minutes (or more) to empty a can of R12, then you should let the engine run (or better yet drive it) for 20-30 minutes to let the system equalize. Then check the temp. at the vent. BTW, where did you get a can of R12? I'm still hoarding my last one.
One last thing, if you over-fill the system you'll start losing cooling capacity. Good luck, Jerry M '78 SC |
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06-28-2003, 04:57 PM
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1978 Porsche 911 SC 3.0
