| No Dash Aircon [message #173033] |
Mon, 11 June 2012 23:00  |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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I've been working on my dash AC. It has never been working(reliably) since I bought the coach 8 years ago.
I replaced the compressor, the dryer, expansion valve and
flushed out the condenser.
I put ester oil in the compressor (after draining out
whatever was in there). I evacuated the system for
30 minutes and charged it with 2 1/2 cans of Duracool.
I have 110 PSI with the engine off. When idling I
get 20 PSI on the low side and 200 PSI on the high side.
It blows cold air at first when idling. After 5 minutes
of running the belt starts slipping. I tightened the belt
and it ran again for about 5 minutes before the belt started
slipping again.
I replaced the belt with a Goodyear 15615 Gatorback.
The new belt doesn't slip. But now the clutch slips.
The compressor gets very hot when this happens.
Any ideas what could be wrong?
Do you think the compressor is clogged up?
Thanks,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: No Dash Aircon [message #173097 is a reply to message #173033] |
Tue, 12 June 2012 13:58  |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Emery,
I heard that Ester oil was compatible with R12 and R134.
I didn't consider that mixing Ester with other oils might
be a problem.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: No Dash Aircon [message #173098 is a reply to message #173033] |
Tue, 12 June 2012 13:59 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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I never did get the revs up to 1500RPM. I shut it off
when the clutch started slipping. The clutch was real hot.
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: No Dash Aircon [message #173099 is a reply to message #173033] |
Tue, 12 June 2012 14:03 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Before installing the compressor, I drained out the oil
that was in it, before adding the Ester oil. I may be
that it had some other kind of oil in it.
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: No Dash Aircon [message #173125 is a reply to message #173099] |
Tue, 12 June 2012 19:26 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Bill What Emery was saying is if there was a measurable amount of mineral oil left it does not mix well with ester oil. I assume you didn't put in too much oil as that could cause the problem you are having? The clutch could be bad or the compressor could be seizing due too to much oil or damaged internal parts. 20 lbs suction at an idle is an indication of a low refrigerant charge. You need to check the suction at 1500 RPM so the compressor is spinning fast enough to pump enough coolant also you will likely need to mist the condenser with a water hose if it is a warm day to keep the head pressure from going too high.If it was a rebuilt compressor it should have come with ester oil in it or Pag oil. You might want to rotate the compressor by hand without the clutch engaged to see if it is seizing up.
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Tue, 12 June 2012 19:39] Report message to a moderator |
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| Re: No Dash Aircon [message #173146 is a reply to message #173033] |
Wed, 13 June 2012 00:00 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Roy,
It was a new compressor (but not anymore). I
think it was set up for R134. I drained out
the oil that was in the compressor and refilled it
with ester oil. I can't remember how much, I think it
was 8oz.
Each time I turn on the AC it's cold for a few minutes, and
then the belt or the clutch starts slipping. I haven't
been able to run it at 1500 RPM (I shut it off when I smell
the belt or clutch burning).
I'll take a closer look at the compressor and spin it by
hand to see if it's seizing up.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] No Dash Aircon [message #173164 is a reply to message #173146] |
Wed, 13 June 2012 06:52 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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It sounds like the compressor is being distressed - having liquid come in the intake after its run a bit. This locks it up solid. Either the belt will slip, the clutch will slip, or something will break. It won't turn when it's full of liquid. Or full of parts from a rpevious failure. I'd remove it and drain and clean thoroughly, clean out the system, inspect the comporessor, and start over.
--johnny
'76 23' transmode norris
'76 palm beach
From: Bill Wevers <gmc1975@att.net>
To: gmclist@temp.gmcnet.org
Sent: Wednesday, June 13, 2012 1:00 AM
Subject: Re: [GMCnet] No Dash Aircon
Roy,
It was a new compressor (but not anymore). I
think it was set up for R134. I drained out
the oil that was in the compressor and refilled it
with ester oil. I can't remember how much, I think it
was 8oz.
Each time I turn on the AC it's cold for a few minutes, and
then the belt or the clutch starts slipping. I haven't
been able to run it at 1500 RPM (I shut it off when I smell
the belt or clutch burning).
I'll take a closer look at the compressor and spin it by
hand to see if it's seizing up.
Regards,
Bill
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] No Dash Aircon [message #173185 is a reply to message #173164] |
Wed, 13 June 2012 10:37 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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If Bill put in the same amount of oil he took out (approximately)oil wouldn't be the problem. The oil removed was most likely the same type as was removed. 2 1/2 cans of Duracool wouldn't cause it to slug liquid. If it was 2 or 3 times that it would be a definite problem. If there is an internal problem with the compressor (bearings etc.) it will certainly cause the problems he describes.
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Wed, 13 June 2012 12:10] Report message to a moderator |
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| Re: No Dash Aircon [message #173228 is a reply to message #173033] |
Wed, 13 June 2012 19:01 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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I didn't see (unless I miseed it sorry) the word VACUUM anywhere in the process. To me this is the classic sign of water in the system. Works at first and then the expansion valve freezes internally and you can't compress against the blockage. Did you pull a vacuum before charging to get rid of the air and moisture????
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: No Dash Aircon [message #173236 is a reply to message #173228] |
Wed, 13 June 2012 19:38 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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| JohnL455 wrote on Wed, 13 June 2012 17:01 |
I didn't see (unless I miseed it sorry) the word VACUUM anywhere in the process. To me this is the classic sign of water in the system. Works at first and then the expansion valve freezes internally and you can't compress against the blockage. Did you pull a vacuum before charging to get rid of the air and moisture????
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I agree moisture in the system is a bad thing but if the expansion valve were frozen he wouldn't have 20 lbs suction. The suction would be less then 0 lbs however noncondensibles(air) from not evacuating or purging the system will give extremely high head pressure which would blow off the relief valve. It sure sounds like a defective compressor to me. Bill is going to see if it feels overly tight by turning the compressor shaft by hand but all bets are off at this time.
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Wed, 13 June 2012 20:00] Report message to a moderator |
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| Re: No Dash Aircon [message #173988 is a reply to message #173033] |
Wed, 20 June 2012 00:57 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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I finally looked at the compressor today.
I could spin it a few turns by hand. But it
took some effort and got stiffer after a few
turns.
So I depressurized the Duracool..NO CFCs WERE RELEASED.
Then I opened the drain plug on the side of the compressor.
Oil came out for a while, about 4 oz. Does that sound
like too much oil?
The oil was clear, not dark or black. I checked the
oil level with a plastic wrap. It was up to the bottom
of the drain hole.
Next I reinstalled the plug. It spun very easily
afterward with no rough spots. So it may be that
I over filled it with oil.
I'll evacuate and refill with Duracool next and
see what happens.
-Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: No Dash Aircon [message #173999 is a reply to message #173033] |
Wed, 20 June 2012 05:35 |
Rick Williams
Messages: 256
Registered: July 2004
Karma: 0
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Senior Member |
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Bill
The A6 compressor holds 6oz of oil and the entire system needs 10.5 oz. You should probably flush the entire system and start over so you know how much oil is in it.
Rick
Rick Williams
Bliss, Michigan
1978 Eleganza II
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| Re: [GMCnet] No Dash Aircon [message #174022 is a reply to message #173988] |
Wed, 20 June 2012 09:02 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Bill,
Be aware that you could still have excess oil out in the system
collected in low points. Bottom of the condenser, dryer and possibly
in the lines. If it works fine then your probably OK, if it reoccurs
then you may need to drain and flush the entire system to remove all
oil and contaminants and start over with a single oil (NAPA # 209500
Wax free mineral oil) and a new dryer NAPA 208508. If you are forces
to drain and clean it would be a good time to change out all the old O
rings in the system to the Green O rings.
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 Buskirk 30' Stretch
1975 Avion (Under Reconstruction)
Michigan
On Jun 20, 2012, at 1:57 AM, Bill Wevers wrote:
>
>
> I finally looked at the compressor today.
> I could spin it a few turns by hand. But it
> took some effort and got stiffer after a few
> turns.
>
> So I depressurized the Duracool..NO CFCs WERE RELEASED.
> Then I opened the drain plug on the side of the compressor.
> Oil came out for a while, about 4 oz. Does that sound
> like too much oil?
>
> The oil was clear, not dark or black. I checked the
> oil level with a plastic wrap. It was up to the bottom
> of the drain hole.
>
> Next I reinstalled the plug. It spun very easily
> afterward with no rough spots. So it may be that
> I over filled it with oil.
>
> I'll evacuate and refill with Duracool next and
> see what happens.
>
> -Bill
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: No Dash Aircon [message #174055 is a reply to message #173988] |
Wed, 20 June 2012 12:09 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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| bwevers wrote on Tue, 19 June 2012 22:57 |
I finally looked at the compressor today.
I could spin it a few turns by hand. But it
took some effort and got stiffer after a few
turns.
So I depressurized the Duracool..NO CFCs WERE RELEASED.
Then I opened the drain plug on the side of the compressor.
Oil came out for a while, about 4 oz. Does that sound
like too much oil?
The oil was clear, not dark or black. I checked the
oil level with a plastic wrap. It was up to the bottom
of the drain hole.
Next I reinstalled the plug. It spun very easily
afterward with no rough spots. So it may be that
I over filled it with oil.
I'll evacuate and refill with Duracool next and
see what happens.
-Bill
|
If the drain plug was totally at the bottom when you drained the 4 ounces out and emptied the compressor of oil, being it holds a total of 6 ounces I don't see how the system is over filled with oil unless it didn't all come out. What usually happens when a system has too much oil in it the oil returns to the compressor while it is running and you wind up with an excessive amount of oil in the sump. I once drained 6 gallons of oil out of a commercial Trane compressor(a little at a time) that should have only had 1 gallon in it. After I fixed the break in an internal compressor oil line gasket the excess oil started coming back to the compressor.If the sump is too full it will certainly cause the compressor to lock up. I would make sure you did drain the total amount of oil from the compressor then put the correct amount back in before you try it again.If the plug is on the side it may be the full line? If the compressor was kind of binding when you turned it by hand in one direction then loosened up when you worked it back and forth I would say you need to bring that new compressor back to the place you got it and get another one but only when you are sure the sump had the correct 6 ounces in it.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: No Dash Aircon [message #174126 is a reply to message #174101] |
Wed, 20 June 2012 20:40 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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Bill: I looked at the X 7525 maintenance book and it suggested a small amount of oil should come out when the plug is removed but it didn't say how much. At this point of your dilemma what I would do and I hate to suggest it would be to rotate the compressor till the plug is on the bottom and drain the rest of the oil. Don't forget to rotate the compressor crank some to get the rest out. If another 4 ounces comes out you will know you were 2 ounces too much. I kind of doubt that would have been enough to cause your problem. If it turns out you had 6-8 ounces in the compressor I would suspect the compressor has an internal problem and exchange it under warranty since you are 1/2 way there now. I know that thing is heavy but putting it in and out will make you stronger.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: No Dash Aircon [message #174411 is a reply to message #173033] |
Sat, 23 June 2012 21:03 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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I removed the compressor and disassembled it.
It did not look damaged inside.There were a few
ounces of oil in it. Not excessive oil.
The oil looked clear. I did not see any score marks on
the cylinder walls.
Then I removed all the hoses and blew them out with compressed air. I did not see any debris coming out.
I took out the expansion valve it was not clogged.
Then I noticed that my pressure cut-off switch is a LPCO GY109.
It cuts out at low pressure only. Shouldn't there be
a high pressure cut-off switch? Maybe the pressure
is too high causing the clutch to slip.
I think I need the correct pressure switch.
-Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] No Dash Aircon [message #174413 is a reply to message #174411] |
Sat, 23 June 2012 21:22 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Bill,
You have the correct switch. The GMC AC does not use a high pressure
shutoff switch.
Do you have the factory maintenance manuals? If not you should invest
in one of the sets available on CD so you could trouble correctly or
download them from Billy Masseys site. They are not very expensive or
free if you download them yourself. <http://www.bdub.net/factory-manuals.html
>
JR Wright
On Jun 23, 2012, at 10:03 PM, Bill Wevers wrote:
>
>
> I removed the compressor and disassembled it.
> It did not look damaged inside.There were a few
> ounces of oil in it. Not excessive oil.
> The oil looked clear. I did not see any score marks on
> the cylinder walls.
>
> Then I removed all the hoses and blew them out with compressed air.
> I did not see any debris coming out.
>
> I took out the expansion valve it was not clogged.
>
> Then I noticed that my pressure cut-off switch is a LPCO GY109.
> It cuts out at low pressure only. Shouldn't there be
> a high pressure cut-off switch? Maybe the pressure
> is too high causing the clutch to slip.
>
> I think I need the correct pressure switch.
>
> -Bill
>
> _______________________________________________
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: No Dash Aircon [message #174419 is a reply to message #173033] |
Sat, 23 June 2012 22:29 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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Thanks, I'll download the manuals.
I'm going to clean everything good with mineral spirits
and put in a new drier....
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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