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Hello,
my 92 retrofit was blowing cold until a day or two ago.
symptons:
1) it's kinda cold at low speeds, but now slight fog is coming out of the vent
at higher speeds, maybe icing up?
2) i haven't measured the temp in the vent and i haven't gauged the low side,
yet.
3) the a/c compr never has cycled on and off since i retrofitted it.
4) i haven't really seen any condensation under the car.
5) no smell of coolant.
a/c was not working when i bought it last august.
i've seen this before but many years ago--can't remember.
i've done an archive search, but can't find specific symptoms.
thanks as always!
byron golden
86 245
92 245
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conclusions.
1) a/c h/press line icing up.
2) a/c not recycling.
how i solved:
1) low freon, maybe slow leak. my 86 hasn't needed freon in 2 years by comparison.
2) a/c non-cycling caused by defective pressostat (low press switch). i picked a spare up in the junkyard off a 92 last fall.
i put the spare one on just to check, and presto, now my a/c compr is cycling.
i'll the rate of loss in freon before i check into low freon.
hope this helps anyone in the future. sometimes, it's good not to have too quick of replies--forces one to dig into the problem.
regards,
byron
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If the pressure switch was bad and it wasn't cycling and it was icing up, it may have had the correct amount of freon in it to start, when the compressor doesn't kick off, the suction side will continue to drop in pressure while the hi side increases.
You may possibly have overfilled it.If it's noot getting as cold as it did, you'll know.
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '82 Mercedes 300SD for sale
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hello robert,
you might be right. i did check the low port with one of those cheapie plastic gauges which came with the can.
it is nice and cold, and the real test will come in a few days when we warm up here in houston with that life-sapping humidity.
thanks for the reply.
regards,
byron
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Houston is the torture test for any AC system ( and I complain about here in Arkansas :-)
If it isn't acting right, you may need to get ahold of a cheap dual gauge set and check the high side to see if it needs adjusting. You can download a free program AC advisor from this site : www.aircondition.com that will calculate high sidepressures for the ambiant temp among other things
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '82 Mercedes 300SD for sale
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posted by
someone claiming to be Bond. James Bond.
on
Sat Apr 30 07:27 CST 2005 [ RELATED]
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For improved performance, you need a switch calibrated for r-134a. The one you took off the junker may work, but IIRC, previous posters have said that the 1992s were set up for r-12 (mine was until I had it converted) and used a 27-lb low-pressure switch. The r-134 systems on the 1993 and later (maybe even a switch from a 900 series would work) is set for 20 lbs pressure.
I don't claim to be an expert on AC, but this is the way it's come across to me.
Good luck.
Doug Harvey
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Hello Doug,
I didn't know, thanks for the tip. there are some later model 940s in the junkyard. i'll grab one.
byron
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1) low press side indicated low freon, & added freon.
2) after adding freon, low press plastic gauge says around 30.
3) still a little icing up, very cold from vents. no temp readings made in vents.
4) significant change.
5) ambient temp about 60F
i may have a slow leak.
Questions: still 1 problem, a/c not cycling off.
low or high switch? how can i tell which one?
I know it's a little cooler now, but shouldn't the compr cut out?
thanks to all!
byron
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additional info this morning, 92 240
the hi pressure line from orifice tube to firewall frozen.
low press reading about 15 lbs.
low freon, will it cause the line to freeze, and probably the evaporator?
can a clogged orifice tube do this?
hope i gave enough info.
regards,
byron
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