1990 240 wagon ac project

edelmatt · Post by **edelmatt** » 12 Jun 2014, 12:57

Working down the list of ills for my 1990 240, the AC is up next. It appears to be the original R12 system. I gather this by the fact that there is still the 'factory fill' fitting downstream of the drier.

Unfortunately I can not find any specific diagnostic guide for this year of 240. I don't even know where I would connect a manifold diagnostic gauge. Would the service ports be around the receiver/drier, compressor, or condenser? If the receiver/drier, do I then need to remove all the interior panels to reach the service ports? The most likely seems to be that both high/low ports are on the compressor and a PITA to get to.

Thanks for any help. Especially if there is a PDF guide for this specific AC system (Diesel-Kiki compressor).

93Regina · Post by **93Regina** » 12 Jun 2014, 16:05

edelmatt wrote:1990 240, the AC is up next.

I'd have to see it, but high side pressure-port might be behind compressor, and low side on GM's dryer.

In 1993, Volvo used 134a, so previous systems are R-12

With older systems, once 134a is installed, the compressor's sealing rings blow out, sooner or later.

I did not read thru this thread, but if you plan on using AC seriously, then it may be better to upgrade to a newer compressor designed for 134a usage.

On 1993-245, Volvo installed a pressure-relief valve.

Also, fan clutch should be changed out, and maybe a new radiator is in order.

Post by **abscate** » 12 Jun 2014, 18:22

Make sure you can get access to R12 before you dive into this, if you are keeping the system R12 compatible. In our state, you can't get it.

93Regina · Post by **93Regina** » 12 Jun 2014, 20:54

abscate wrote:Make sure you can get access to R12.

Alternative Refrigerants for R-12

edelmatt · Post by **edelmatt** » 12 Jun 2014, 23:24

I'm about 99% certain I can get R12 or a substitute, as I mentioned above. First I just want to run a diagnostic. I see now where the high and low ports are down on the compressor. Now I need to get a gauge and the proper fittings. I haven't yet measured but the ports look to be about 3/8". Does that sound right? I'll measure tomorrow morning and figure out what I need to buy.

I'm hoping that a) the compressor is still good and that b) I can isolate any blocked component. Then i can borrow a pump or take the car somewhere to have the current refrigerant drained so I can replace anything necessary. Then I can decide whether to go with R12 or do an upgrade. Anyway, diagnostic first. It'll be a while before I post again as it will take a while to get through all that.

93Regina · Post by **93Regina** » 13 Jun 2014, 07:44

edelmatt wrote:Then I can decide whether to go with R12 or do an upgrade..

Maintaining a AC system is not cheap; and if po(s) didn't, then its not uncommon to spend several hundred bucks to bring it back.

Might check a pawn shop for used R-12 gauges...they are essentially history now.

Drop by a AC shop, they can point out where low/high ports are located; if you have a GM dryer (silver tube) next to firewall on passenger side of engine, there is a low pressure port there. Just just using low pressure gauge, one can evaluate quickly a AC system.

Here is what is needed, A/C COMPRESSOR + NEW KIT, to do it the right way. But, the price shown there is quite cheap. To convert to 134a, the system needs to be flushed, another 30 bucks or so, and you need a vacuum pump.

I'm sure shops get around 500 bucks and more when they do a complete change over, with new/rebuilt compressor that you provide.

edelmatt · Post by **edelmatt** » 13 Jun 2014, 11:38

93Regina wrote: Maintaining a AC system is not cheap; and if po(s) didn't, then its not uncommon to spend several hundred bucks to bring it back.

Thanks. I'm currently evaluating my options. As you've said, tools/freon/time isn't cheap. And the PO was definitely a 'cheap way out' guy. He even lied to me about the AC saying it just needed charging. Shame on me for falling for that one!

The system does not have the GM component next to the firewall. Just the cylinder with the sight glass next to the radiator, then a hose straight into the firewall. When I look into the sight glass with the car off and compressor off, it looks empty. Should I see something when it's off?

93Regina · Post by **93Regina** » 13 Jun 2014, 15:33

edelmatt wrote:cylinder with the sight glass

With a sight glass, one does not need a gauge, but one needs to gently clean off sight glass, and have a good flashlight (or light) to view it. When unit is running, if bubbles exist on a HOT DAY, it means refrigerant is low. When refrigerant turns to a liquid (clear), it is full.

When vehicle is tested at home, a fan needs to blow across radiator/condenser.

When looking at front center of compressor's clutch, is there oil there? Unless PO or yourself is a clean freak, there may be oil there indicating compressor's front seal is shot.

There is a technique to installing freon; from vehicle's system, a little must be back-feeded thru the line that will furnish freon. Hence, no atmospheric air put into vehicle's system.

Now, there is most likely a low pressure switch on that cylinder, if plug is removed, and if a jumper wire is inserted there on that plug, with AC turned on, compressor's clutch should run. But, this is done manually for a second or two at the hood-side, so you can see if clutch engages. The engine does not need to be running, just turn on switches for AC and turn ignition key. If clutch engages, then vehicle is low on refrigerant.

Post by **jimmy57** » 13 Jun 2014, 16:15

And the engine needs to be run at 1200-1500 rpm as all manufacturer's A/C servicing has you do to get a/c compressor fast enough to be effective.

edelmatt · Post by **edelmatt** » 13 Jun 2014, 16:27

93Regina wrote:When looking at front center of compressor's clutch, is there oil there? Unless PO or yourself is a clean freak, there may be oil there indicating compressor's front seal is shot.

Clean. So the seal must be OK.

My neighbor, who is almost always just sitting in his garage (ah, retirement), came over and helped me look for a while. We found that the compressor clutch wasn't engaging unless the interior AC knob was set at a very particular spot. Seems that perhaps that switch/knob is faulty. Once we got it engaged, the sight glass was showing a lot of bubbles. So, refrigerant low. And I'm hoping this also indicates that there is not a blockage in the system. Would the bubbles be dancing around if there was a blockage?

I drove the car around for about 20 minutes to see if the system would cool down. It did not. So, hopefully just low on refrigerant to the point that it isn't cooling.

My next move is to ask my other neighbor who does AC service for a living, if he could give me a hand recharging the system.