FAQs about Air-Conditioning

How do I replace the A/C compressor pulley/clutch?

From Bill_Blake@vos.stratus.com Thu Apr 16 15:28:36 1992
Date: Thu, 16 Apr 92 15:03 EDT

The A/C compressor pulley/clutch is a piece of cake to do. I am speaking about the assembly that is attached to the York A/C compressor, found on most early to mid 80s 240 models.

Back off the power steering drive belt and remove the aircleaner box, this will give you complete access to the pulley/clutch. I did not bother to go through the pain and suffering of removing the A/C drive belt from the crankshaft. Next insert a plain blade screw driver through the pulley/clutch to jam it, you may have to push down on it (screw driver)as near 90 degrees as you can, while removing the 1/2" locktighted holding bolt located centrally. This really shouldn't be difficult as the bolt is suppose to be down at only 20 ft/lbs. Once the central fixing bolt is removed you can screw in a commonly available 3/4" coarse threaded bolt, while jamming the pullet/clutch assembly. This will separate the assembly from the compressor shaft. BEWARE of loosing the shaft key, mine stayed on the shaft but the instructions I had warned me about this, so I pass it along. The belt will come along with the pulley. At this point you can replace the magnetic coil by removing the 4 retaining bolts and pulling one electrical connection, if you are so inclined. I replaced mine only because I had the new one, they are really almost inert and would only be damaged if the pulley when really wild.

No special notes on reassembly. I do suggest, however, that you do a couple of loose "dry fits" of the new pulley/clutch to get the feel for how the shaft key engages the tapered bore of the pulley/clutch. Also if the drive belt was adjusted correctly before you started it should be fine when it is reestablished, just don't forget to put it on the correct groove of the pulley prior to final fit. The new central fixing bolt will come with a drop or two of locktite already in place, if you are using an old one apply two drops of either locktite red or blue, torque to 20 ft/lbs. Do take the new part with you to the hardware/auto parts store to insure that you select the correct bolt, that will function as the puller.

I was pleasantly surprised that the entire procedure took about 30 minutes, wasn't a knuckle-buster and removed a real irritating vibration. The parts cost me $90 from Jafferian. If you have any further questions I'd be happy to take your call at W: 508-460-2873 or my home at 508-568-8742.

Good Luck!

From: hwiegman@EW0040.ASTRO.GE.COM (Herman L Wiegman)
To: JWRPPH@ritvax.isc.rit.edu
Subject: Re: A/C belt tension John, and other who replied to me,
From: "John W. Retallack" <JWRPPH@ritvax.isc.rit.edu>

> Mine's a York... sits on the left side of the engine (driver's side). There seems to be no provision for increasing or decreasing the tension of the belt.

When one tensions the A/C belt it is done via the "engine" pulley. The system came in around '76 and stayed until '90.(??) anyone? It is used on all York equipped cars. (me thinks)

The main pulley has a cover plate or "face" which is bolted on. This face holds the A/C belt onto the pulley. It also tensions it with the amount of "squeeze."

There are no other places to tension the A/C compressor.. it is not like the power steering pump or alternator which have radius arms for adjusting the belts. The A/C load is brought on with a huge pulse and can easily loosen radius armtype tension mechanisms.

(Amazing ASCII art..) Cross sectional view of engine pulley.

Pulley-> \BBBBB/ <- cover plate or face.

\BBB/ |_/ B = A/C drive belt Engine || side || <--- Nuts -------- | <-- shaft -------- || .. ..

The spacing washers go between the Pulley and cover plate. The two halves make a complete pulley surface, or "V," for the A/C belt.

The water pump and alternator belts are "inboard" of the A/C belt, i.e. one has to remove the A/C belt to change them... All in all, not a difficult job.

Leaking freon/freon sniffer.

Date: Fri, 14 May 93 16:47:59 EDT
From: mike@oracorp.com (Michael Meador)
To: swedishbricks@me.rochester.edu Subject: AC troubleshooting

Don't let anyone muck around with your AC system unless they have a "freon sniffer". This moderately expensive device can detect very minute concentrations of leaking freon. I spent way too much time and money on failed attempts by ill-equipped mechanics. Finally, one with a "sniffer" quickly discovered and inexpensively fixed a bad O-ring.

Date: Mon, 21 Jun 93 11:43:07 CDT
From: u6946@sequoia.cray.com (David Dannenberg)
To: bausman@mcc.com
Subject: Freon leaks

In my experience with a freon leak on a 1979 245, I took it to 2 different "independent" mechanics. Neither could find the leak, but they added more freon and happily charged me for this "service". Finally, in desperation, I took it to Val Strough Volvo in Pleasanton, CA (which has just changed hands and is now Pleasanton Volvo). They have a very expensive "sniffer" which immediately located the leak in a hose. One hour's labor plus the hose and the freon was the total cost. For tough-to-find leaks, I believe you're ahead by going to someone who has the right equipment. These back alley mechanics just can't afford the expensive sniffers, and they don't appear to be eager to recommend a repair shop who has one. I suppose there may be specialist A/C shops who have the right equipment and yet may charge less than dealer labor rates, but I'm not aware of any in this area.

This whole process took place over a period of 2 years, going back & forth to the independents who would scratch their heads, add more freon, and then wish me well. Sometimes in frustration, I would simply add the freon myself. (It was a "slow" leak.)

This is only one person's experience, but I would have been ahead if I would have gone to the dealer in the first place instead of trying to save a few bucks dealing with independents. Obviously, the independents have their place but caveat emptor (let the buyer beware).

I'm seeing bubbles in the site glass in the air system.

From: nessa@mentor.cc.purdue.edu (Vanessa M. Cook)
Subject: Re: Air Conditioning Service
To: swedishbricks@me.rochester.edu (Volvo-Net)
Date: Sat, 15 May 93 10:51:32 EST

Marvin Bausman writes...

{ Looking at the sight glass in the air system, one can see many bubbles in it when it is running. I am not an expert at air, but have worked on a few Chevy systems as well as having kept the air in my 1800ES operating well. If I remember correctly, the bubbles indicate a low charge of freon.

OK... if you want an easy fix and don't mind damaging the ozone layer just put Freon into the system until the bubbles just go away. Oh yeah, put the freon into the low pressure side of the compressor. With the system running you should JUST NOT be able to see bubbles.

If you take it to some else they may fix it or not. They will most certainly charge you a rather large amount of money for whatever they do.

You might want to consider using one of the new self sealing mixtures that are on the market. You can even use the stuff meant for R-22 if you want. This stuff turns into an epoxy when it comes into contact with Oxygen and turns into silicon lubricant when it comes into contact with water.

{ My question is: is it worth my while to try to service the

{ unit myself or should I just break down and take it to

{ someone knowledgeable? I do have some cans of Freon on

{ hand, although I have heard that they are hard to come by

{ now. If I do take it to someone, is there anything specific

{ to the Volvo units that just any old air conditioner service

{ person might not know? Should I look for someone with

{ particular experience with Volvos?

1. Unless the person does ONLY A/C work they are not necessarily knowledgeable. My mechanic is wonderful on most things but NOT A/C work. :(

2. Volvos have a rather old system in them. Any one who knows A/C will have no trouble working on your brick. (Heck, Volvos still have expansion valves. Most systems have metering ports.)

Brian.

--

Shorted out the receiver-dryer.

From nessa@mentor.cc.purdue.edu Wed Jun 2 15:41:35 1993
Subject: Re: 240 AC prblm
To: swedishbricks@me.rochester.edu (Volvo-Net)
Date: Wed, 2 Jun 93 14:34:01 EST

Mike Sestina - Sun BOS Hardware writes...

{ { I short the two wires that go to "something" on the (I think it is { called) receiver/dryer. U know, that cylinder on pass side { front near the radiator that has AC hoses plumbed in to it and a { "thingy" with the two wires I shorted on top.

Yeah, don't force the issue with this protection switch. It is a low pressure cut-out switch. If there isn't enough R-12 in the system to keep the oil in the system circulating the system will not run.

{ loss of R-12? I think I see coolant in the sight glass but no { bubbles when compressor cycles. Does that mean (he sez hopefully)

{ I can repair the thingy myself. Or (gulp) is this gonna be an { expensive AC repair and/or refill/test?

If you should get the R-12 to fill the system again. You can use the sight glass to get the level correct. You fill the system until the bubbles "just" go away. This with the engine running at approx. 2K to 2.5K RPMs. If you put more than this you will run the system at HIGHER than normal Compressor Head Pressures. This will lead to the early retirement of said compressor. You should try to do this when the ambient temp is above 70 or 75 Fahrenheit. This will let you charge the system when it is actually doing work. BTW... Open the windows and run the system at MAX. BTW2.. If you are able to get a hold of the R-12 and charge the system.. DO NOT connect the cylinder or Blow-off Cannister to the HIGH side of the Compressor. Doing so could cause the container to EXPLODE and you could suffer severe damage, even death. (Major Bummer... :)

There is a company called Cryo-Chem that makes a sealant that you can put in your car that will seal small leaks at joints, etc. (It will not fix shaft seal problems or leaks through the hoses.) believe the kit cost somewhere around $100.

Final BTW....

If you go to a shop... Check to see if they have proper licenses and such. After all if you can't do it and are going to pay them they bloody well better be qualified. Also, If they do not have a deep pump and micro Vacuum gauge don't let them do any more than add more R-12 to your system. There is NO "sealed compressor" type vacuum pump that can draw a good enough vacuum to remove moisture from your system if there is a problem with this. I don't know of any mechanical Vacuum gauges that work at deep vacuum either. The tube type ones are best. :) If you intend to do it yourself.

FWIW The EPA decided that BLENDS are not allowed. I guess too many people "convinced" them it was bad. READ: Lots of people with lots of money to be made off of the rest of us at >$100 per charge, etc.

--

Brian & 'Nessa and Herman (the ferret)

"Maybe it's a gift, a special talent that I, alone, possess!" --Wembley "Maybe it's a curse, a special weirdness that only you are stuck with!" --Red

From: JML12@psuvm.psu.edu Date: Wed, 2 Jun 93 12:38 EDT
Subject: Re: 240 AC prblm
To: Mike.Sestina@east.sun.com

The thingy with the switch you shorted out is the receiver-drier, which removes moisture from the refrigerant. The contacts you shorted on top belong to the low pressure switch, which will not let the compressor operate unless there is sufficient refrigerant pressure to prevent damage to the compressor.

While all it may need is additional R-12, the system probably has a small leak somewhere that requires attention. Unfortunately, R-12 is no longer available to unlicensed individuals in the convenient 12 & 16 oz sizes (you know, ozone depletion). Anyone can buy 20 & 30 lb cylinders (a loophole in the regulation) at their local K-Mart, Wal-Mart, Etc... for around $10 a pound. However, without proper equipment, it is difficult to measure how much R-12 you put into a system from a large canister.

It's probably best to find a qualified mechanic to check the system for leaks, evacuate any moisture that is present and refill the system.

Good luck getting it done for under $100.00!

The A/C works for 10 min. before the expansion valve at the evaporator stops functioning.

From: memsthd@prism.gatech.edu (MIKE WILEMAN)
Subject: Re: A/C info
To: danp@oregon.cray.com (Dan Phillips)
Date: Wed, 23 Jun 1993 00:56:34 -0400 (EDT)
Cc: swedishbricks@me.rochester.edu

> Netters,

I just bought an '85 245DL and have to take it in for a few minor things I can't or don't want to perform myself. The A/C will only work for about 10 minutes before the expansion valve at the evaporator stops functioning due to debris or possibly moisture. I'm having the valve replaced as well as a general system check and new o-rings

STOP! There is probably no need to replace the expansion valve. Your AC is showing classic signs of water in the system. All it probably needs is to be evacuated and recharged. Water freezes in the expansion valve, particularly when the outside temperature is high, so that the pressure difference across the valve is high, and the system is basically blocked until the ice thaws. Usually, when this is happening, a pressure gauge hooked to the suction side of the compressor will look jumpy as the valve freezes, thaws, freezes, etc.

Mike

From: danp@oregon.cray.com (Dan Phillips)
Subject: A/C problem update
To: swedishbricks@me.rochester.edu
Date: Mon, 28 Jun 1993 14:53:17 -0700 (PDT)

Volvo Netters,

This is an update to my recent A/C problem. To recap, after about 15 minutes or so the compressor clutch would not disengage and cooling stopped. I believe the problem was compounded by a confused mechanic who worked on the A/C for the previous owner (I just bought this '85 245DL three weeks ago). My inspection showed that the thermostat had been recently replaced. I suspected it at first myself but upon further investigation found the output of the expansion valve to not be cold enough to allow the thermostat to shut off the clutch. The first time I took it to my mechanic he hooked up his gauges and found the pressure too high. He let out about one pound of freon to get the pressures where he wanted to see them. His diagnosis was that the last mechanic thought the problem was due to not enough freon(where his gauges were I don't know). I drove home and it seemed to be fixed but it was a cool day and I didn't really need to run the A/C.

Well the next day was warm and the failure returned only it took about 1/2 hour this time. I took it back and he replaced the expansion valve, changed some O-rings and recharged the system. I also had him replace the receiver/dryer since it was only $37. He said that he couldn't blow through the expansion valve as well as he felt he should have been able to and labeled it "restricted". I was leaning to moisture or a bad valve myself but without the tools I had them check it out. It's been working for three days of warm weather now and I feel comfortable that I won't be having problems with the A/C for awhile. Thanks to everyone who offered up free advice!

Home A/C work can be done.

From: Mark Nathanson <nathanso@umdnj.edu>
Subject: more on air
To: swedishbricks@me.rochester.edu
Date: Thu, 19 Aug 1993 12:06:02 -0500 (EDT)

Folks, I thought I'd add my $.02 to the talk of air conditioning. I have been doing my own AC work for several years now using a set of cheap Robinair gauges and an old vacuum pump that is capable of 5 microns. Oh yes, my best friend is a Haynes air conditioning manual. I also bought a big tank of freon before the prices got high. Generally, air conditioning service is pretty easy as there are few moving parts and you only have to understand the function of a half-dozen things or so. The Haynes manual is quite good and even gives step-by-step directions for trouble shooting and repair. OK, so I've got tools and some experience...

Recently the air on our '77 264 went out and I added some freon from my tank. Wallah! no cold air. Okay, my gauges showed high prressure on the high side (ie. bad expansion valve) and I decided to change entire valve assembly (with dryer) as a good preventive measure. Opening up the valve assembly I found...one of the valves was missing entirely. I should point out that this car was recently rebuilt for my wife and I never looked at its air, or really used it much. OK, purchase whole new assembly, recharge. Wallah! no cold air. Gauges showed high pressure on low side and low to normal on low side. Bad compressor. OK I have an extra compressor. Let out freon, swap compressor, recharge. Wallah! no cold air. Gauges show somewhat low on high side and the needle vibrates. I go to the dealer...

Dealer says 150psi on high side (GM A6 compressor) is not bad (Volvo and Haynes say 200+) and maybe my gauges are cheap so they vibrate. So much for my cheap gauges. Anyway the mechanic says my AC work is fine and starts to check out the car. It seems that the heater control is out of adjustment and I have been driving with the heater fighting the Air!!!! Moral of the story...check your heater valve.

Well, it all cost less than going to an AC shop and I learned something. The price of experience seems to go up like that of tomatoes.

CFC-free "retrofit" air conditioning kit for certain prior model Volvos.

Date: Fri, 20 Aug 93 11:58:42 PDT
From: maj@frame.com (Michael Jue)
To: swedishbricks@me.rochester.edu
Subject: CFC-Free swap.

European Car (September '93) reports:

"Volvo now offers a CFC-free "retrofit" air conditioning kit for certain prior model Volvos, allowing existing R12 air conditioning systems to be converted to a CFC-free refrigerant. Installation takes about an hour and a half and the suggested retail price for the required parts is $45. The first kit released will be for '85-92 740 and 940 Volvos, '85-90 760 turbos and '87 760 non-turbos."

Sounds like a deal to be ecologically correct to me...When I need a charge, I'll purchase the kit and install the new refrigerant...hoping that my existing a/c gauges can still be used.

-maj

Date: Tue, 26 Oct 1993 11:14:28 -0500
From: Juan Moran <moran@uxh.cso.uiuc.edu>
To: swedishbricks@me.rochester.edu
Subject: Air Conditioning Retrofit Information

Saw this in another list.

Spotted the following in the 10/4/93 issue of Design News:

CFC-FREE RETROFIT FOR VOLVO AIR CONDITIONERS

---------------------------------------------

"Volvo has introduced a retrofit kit that allows existing R12 air conditioning systems to be converted to a CFC-free refrigerant. The kit replaces a small number of easily accessible components in the AC system, and uses a new oil to lubricate the compressor. It includes: a receiver/dryer, orifice tube, six replacement O-rings, an R134a SAE filler valve, two retrofit labels, three service caps, and 200 cubic centimeters of ester oil as the lubricant. The kit, say Volvo officials, takes about 1.5 hours to install. The first kits will retrofit 1985 through 1992 740 and 940 Volvos, 1985 through 1990 760 turbos, and 1986 and 1987 non-turbos. Kits for other models will be released shortly. The price: $45. Contact: Michael Guerra at (201) 768-7300"

End of article

I know there was quite a bit of discussion from Goble, de Armond, et al

about the viability of a retrofit kit, mostly along the lines that the

inevitable small amount of residual R-12 would ruin the new system.

My middle vents are not blowing cold air, any ideas?

>On my '89 760, the A/C seems to be working properly but there is a
>problem with the vents. The far left and right vents are cold, but
>the middle vents are only moderately cool to lukewarm (depending on
>how hot it is outside). This happens whether the air is being
>recirculated or not, so it appears that some hot air from outside is getting
>in.

>A mechanic suggested that maybe the heater was not shutting off
>completely as it should when the A/C is on, but it seems to me that
>this would affect all vents, not just the middle ones. I tend to
>suspect louvers which may be located in the air ducts.

>It's cool in Texas now, but it gets hot in the summer! Has anyone
>else experienced this problem? Any ideas or proposed
>solutions?

>David Grimm
>dgrimm@tcac.com

Dan Lonce
dlonce@comet.chv.va.us