Hi,

A few years ago I converted my 92 245 R12 system to 134A. I replaced compressor, condenser, hoses, rings, but left the original evaporator. It cools ok, but not the greatest on really hot humid days.

I have access to a complete factory 1993 245 134A ac system. Would exchanging my r12 evaporator with the 93 improve my system? I've been told the factory 134A evaporator is larger and works better. Is it worth the effort?

Thanks, Jim

I see this is an older post. I'm not that active, but very familiar with the 240 A/C systems, and have done a lot of work on them.

There are a couple things you can do to improve the remaining function of the system, assuming that the refrigerant charge is still correct.

Replace the fan clutch.

Flush out the condenser fins with water (if you didn't).

Jump the pressure switch harness on the lower right side frame rail where the pressure switch is attached to the A/C line. This forces the condenser fan to operate all the time when the blue snowflake (A/C) switch on the console is turned on. I had good results with this.

I have also had good luck with the variable orifice tubes in the 240 like you used. I used to get very good performance out of the 2 and 7 series conversions, but only used the variable tube in the 240s. I never felt that any 245 A/C system was sufficient in the hottest weather, even new ones. The later orifice tube designs were better though. The sedans would stay nice and cool, but the headliners were better, and there was obviously a lot less interior space and roof surface area than the wagons.

---------
2005 Volvo S80 2.5T 110k
2006 Lexus GX 470 143k
2013 Lexus GS 350 52k
2015 Subaru Forester Premium 6MT 24k
Plus many past 2/7/9 series Volvos

Hi Matt and Jim,

I have all three models but I have not studied them to any detail. I did go look at the accumulators, during this thread, on the '91 and '93.
Both have 16 mm hoses and the configuration looks the same to me.
They still look different as one has flats on the outside but that is a vendor preference and nothing to do with performance.
The high side going into the firewall is also the same diameter.

To Matt;
I suppose on the condenser being different you are correct, as seeing is believing.
It's look like its hard to see without removing a grill or something. You have had yours out, so there you go, you know better.
Adding or removing a row or using a different vendor could make all that happen.

To all;
If you have a big enough condenser you don't have to even use a fan.
In the relationship of a cars size though that is not feasible plus it's more costly to be done on the manufacturing end.
Adding a fan is a smaller but more dynamic for expelling heat.

On refrigerators and alike the consumer ultimately pays to run that fan! Remember they use to put coils on the backside and there were no fans inside or out the ice box. People were happy with those too, in the Day!
Consumers are now trained to want features and compactness. $$$$.

To Jim or any others;
The evaporators coil size and flow distribution had to change to some extent to improve Volvos sales, as I said earlier.
I have noticed that the charge amounts for both are very different.
The '91 is 2.4 lb of R12 and the '93 is 1.63 lb. of R134a. So they have less to move, so it must go around more times very quickly to get the tons of cooling affect.

In trying to justify a larger condenser though becomes an issue when the system actually holds less liquid refrigerant. This seems contrary to normal thinking?
I would have to conjure up a study and some enthalpy charts for see volume differences or something like that happening here.
R134 was suppose to be less efficient per pound in moving "X" amount of heat by up to Ten percent than R-12. It must not be near that today.
The "A" was added later as a revision to the original R134. I thought the "a" was over an oil compatibility issue, back in the day.
Maybe I'm stuck on the first 134 formulas specifications.
I admit, this is somewhat confusing.

As far as the orifice the 1993 has two variable options and one .067 fixed orifice according to A/Zone. This didn't help me help you as the term "variable" is truly an unknown value.

So with that I will say I am not an Automotive Air Conditioning guru! By any stretch.
I just know big tonnage semi hermetically sealed commercial the most.
Only A/C of my own stuff and a few friends and relatives cars when I get my arm twisted.

But I will say, from all indications, that I see from the labels on the cars and knowing that the R134(a) does have some pressure issues at higher condenser temperatures that an overcharge might be a very good possibility effecting heat removal in a larger quantities.
As I said, this system is very sensitive to the total charge be so, so!

Do you have any idea how much is in there now? Did you use the R12 label on the 1992?
I know my 1993' when I got it last year, did not work but it was mostly due to the console switch was not closing. That switch got me a nice discount on the selling price.

I could not tell how much refrigerant was in the system but it had at least some gas pressure but would not stay running or cool any!
I was not near my home with the shop so, I put in only one can of R134a in. It has been working fine for us. It might be slightly under charged but that is always better than an overcharged system.
Those bean counters again made it hard to check that high side on these cars!

You are stuck taking temperature readings on the condenser and using that "rule of thumb" of up to 25 to 30 temperature above the ambient temperature to know if the condenser is getting hot enough.
The top should be the hottest point and down mid way or 2/3's you should see most of the heat transferred out of the gas. The liquid, collecting at the bottom, will still be rather warm.

An overcharge will slow down the recirculating of the liquid between coils.
The buckets of water are not coming fast enough to put the fire out in the cabin.

Let's see what happens from here?

Phil

Phil, Matt, and Chris,

Thanks for the great info and ideas. I'll be working on those this weekend and will see how it goes.

Phil, when I filled the system with 134A I did exactly what the conversion shop suggested. Evac for couple hours (held tight vacuum), then charge. If I remember correctly it took around 28 ounces (2.5 12 ounce cans) of freon and 8 ounces of PAG. I called them while I was charging it, gave them my ambient temps, etc, they said continue the freon charge until it won't take anymore.

Chris, good to know the variable orifice is ok. I'll check the other things. My fan clutch is fairly new. The condenser was cleaned and flushed, inside and out.

Another thing is I'm basing part of my lack of cooling by comparing it to our new XC70. I know I'll never get to that state of cool, but when it's 95F, humid, and sunny, my vents are blowing 80-85F which isn't great. At 80F, 50%RH, and overcast, it's ice cold. It has always been like this so maybe I should start over? I can reclaim the freon, evacuate, start fresh. Is there anything in my evac/charge procedure that seems off?

Thanks for the great info.
Jim

I prowled the you tube tonight to find layman’s talk. The chart people will drive you bonkers but the charts have their place, mostly hidden away someplace! (-:)

Now on with the rule of thumb in action!

He uses 20 degrees as his constant but it can be as high as 30 degrees under idea conditions in most cases.
This gets proved later.
https://m.youtube.com/watch?v=15ZrpM41enE

Now you will hear 30 degrees mentioned as rule of thumb on and older 10 seer A/C before 2010. Phased out R-22.

Here:
https://m.youtube.com/watch?v=c3IieMtRMUQ


Now with a different refrigerant R-410 along with the quickly mentioned larger condenser, now for me, the game is on with big units he mentions. You need equipment to be tough 24 hours a day!
It also shows a thermal expansion valve for the metering device to more effectively flood the evaporator. Again a sensor is needed.

The rule of thumb number changes to 25 degrees change in temperatures Thumbs come in different sizes but the whole theory is the same thing!
On a car, with the radiator next to the condenser, it’s tricky to get true temperatures, so, this wiggles my thumbs!
Just look for change down the condenser.
Do you have a digital thermometer with dual leads or infrared thermometer?

Here:
https://m.youtube.com/watch?v=JkaG_F-9hD8


Note the tremendous difference in working pressures that he talks about with the R-22 replacement R-410. It must move more BTU’s per pound or its sent around more times at those pressures. Like R-134a is different too!
In my book this means more work has to be done but he says it’s a SEER of 13. This is supposed to be better. ?????

Nowadays it’s higher up than this but the power to the compressors motor and speed is controlled more tightly, electronically, to the “sensed” heat load!
The coils of units are limited to space, as I mentioned before and the TXV.
Not a fix orifice as it’s just not a dynamically cheap way to go anymore. The deal is on the electric power modulation.

SEER 13 is a more costly unit to purchase up front and payback time, well, if you truly get into the nuts and bolts, it is longer!
Today’s refrigerators are being sold as to only last Ten years? Say what?
Consumers must be aware of this, in a throw away world!

Notice the amount of space drawn above the two different coils, showing the states of change and the magic happens on either side of the cycle.
That space or balance is crucial to the design of the orifice in our cars.
The variable and the fixed orifice need to be nailed into those zones of the enthalpy charts for each refrigerant. This is where I stress the importance of watching evaporator icing

The Rules of Thumbs for superheat are protection (mentioned as insurance) to keep the hammers away from your compressor.

You said the other one just stopped and that got you into doing the repair.
I’m even more curious to what you are going to find out about the car system.

Phil

Hi, Jim again!

I forgot to mention that the oil charge appears to be right as well. This is if you started out with a clean and oil dry system. Adding new components is when you add more than what the compressor calls for.

I’m curious how you put the oil in the system though. Adding two ounces directly into the condenser may create some blockage, for a while, until it works past the orifice.

In looking back over your post, 28 ounces might be a couple ounces heavy but that depends on any loss in the hoses being hooked up.
I was thinking that you might have read the label on the car!

If you used that 92’s label then you are stuck with a can too much refrigerant. I’m not sure that this type of system would cool, at all, with that much in it.

Of course, you can take it out if you need to adjust it.
If there is a size change of the condenser or evaporator the only way you can set the system up is carefully taking measurements of tubing temperatures, of which, relates to pressures also and get there.
You can then plot those readings on an enthalpy chart to find out where the refrigerant is working in its curved envelope.
Like I said, the orifice systems are very particular about the charge being balanced.

It seems like you did everything right installing the compressor and clearing the system.
Without observing sweating points, low side temperatures and head pressures points or temperatures, we don’t know where the cycle is failing.

Keep us posted on what you can find!

Phil

Hi Jim,

Yes Jim, I think you are overcharged with R-134a as there as a difference in their behavior and the amount required between the two systems are quite different.
All of this I have contemplated into a theory that you are over stuffed!
The flow of refrigerant is compromised at all temperatures and it gets only worse if the quantity contained gets heated even more by a higher ambient surroundings.

The volume of liquid in there make more gas but it cannot move between the two coils.
Therefore, the system stops working even more.

All refrigeration systems work on a pressure differences and shuffling the liquid. In the R134a case, it going around many times and needs too, very quickly.
You probably have not seen the variable orifice work correctly for this reason.

Since you know the defined quantity in there, the system is all clean to go on working all you need to do is to recover that much in the weight difference.

Now, I only have a really super cheap recovery system. It involves a clean empty refrigerant bottle or can.
I pull a vacuum on the vessel and surround it with ice. A wee bit of water can improve thermal conductivity to condense the vapor towards the vessel. It is not really necessary if it’s hot outside or inside the car.
I use a postal scale carefully to allow for any pressure applied by the hose connections.
A scale to hang everything by, like weighing a fish would probably fit the bill. I don’t do sport fishing or sports as far as that goes, so I have what I have.

It takes time for the gas to move but this is a small system but still bigger than a refrigerator.
On other type systems, that have actual service valves, I use the compressor to pump the gas over into the receiver or chilled , if needed, spent gas bottles.
Refrigeration tradesmen never blatantly released refrigerants long before recovery systems were marketed or mandated by EPA wiz kids!
Recovery systems are fancy but very costly years for small shops and companies.
As long as you try to comply to the EPA rules your license is not in jeopardy.

YOU SEEM TO KNOW WHAT YOU ARE DOING!

Go for it, as you are not losing anything!
Phil

HI,

I may not be much help to you on this one because I have not dug into either of my three ('91-'93) cars to see if there is a difference.
I have been living under a precept that Volvo made the change to the bigger evaporators by the 1991 model year.
The earlier Volvo systems were undersized from the respect of the American cars capacities. Americans go big and bold on most everything.
Volvo knew if the switch to R134a that it would cost up to a 10 percent drop in efficiency. This would crimp the ability to sell their cars. The word was already affecting the sales mid to late eighties sales that was a large jump for Volvo.

The mandate in the USA to switch over to R-134a was approaching. For cars it was wavering to be set for 1996 or sooner. The big kicker was the removal of R12 manufacturing. This cut line was for 1992 globally.
I do not the exact year when Volvo went to the COT system, used in GM cars but the influence was around. It may have been earlier the 1991 with the change to the LH 2.4 driven by the big word EMISSIONS.

1991 was the year I stocked up with 60 lbs. of R12 @ about a $1.50 a pound. I have just opened my second 30 lb. cylinder last year as I have 5 of my 6 cars using R-12. I also topped off my neighbors two vehicles for 15 years until he passed away. I think I have enough until I do!

The R-134a is now indangered but the R-1234YF has its on issues in Europe and those people are not liking our EPA fir approving it! Mercedes says its flammable, in some way or another, but I have not read a lot about it.
The reason I can remember the numbers, is because, I think that the YF stands for "Yell Fire." (:-(

So in looking over the list of those things you change out, I noticed no mention of the expansion device or orifice tube.
I figure you may have done the conversion due to a compressor failure or the lack of R-12?
Changing the condenser side was not so much a big deal unless it was contaminated.

The fan was added onto these cars to help with a limited its size issue in overall design of the front end of the car. The console had its issue with the fan too.
Even if the condenser moved to more rows this would necessitate a needed fan anyway.
Questions came up about, how much money to invest in the 240 with the style in other models selling?
Again, I'm just not that familiar but someone on here may have a parts catalog that will tell you more about evaporators used and the orifice tubes offered.

The opening of the orifice probably comes in more that one size and are denoted by color.
Do you know what the color is that is in your car today?

You might be able to move up a step or two. This will allow a tiny more liquid inside to put out the fire in the cabin.
It's an adjustment that can be done provided you watch your low side pressure range and being mindful of flood back into the accumulator when the cabin temperature is satisfied.

The fan in the cabin is your temperature control. The pressure switch decides the rest and that is pretty much it.
This is a cheaper system to install in their cars but it has several drawbacks to the TXV.
ONE it does not know where the liquid is in the tailpipe of the evaporator to the accumulator. It's in the accumulator it stays or is trapped until it boils off.
It is a balanced charge system and is more subject to rise in outside and inside temperatures like domestic refrigerators that I have written about.
There is a built in margin of safety as the systems are shipped around the world.

It should be possible to adjust it some, to the more tropical climate that you may have. This is why there are various colors available.
Since you have change out your own system, you might be up to a skill level, to move in the range of operation.

So I will let you contemplate this option if the evaporators are all the same.,

Good luck and post back what you find out for all of us!

Phil

"...I noticed no mention of the expansion device or orifice tube...."

I was wondering about the same thing.
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

Thanks for the ideas and good info Bricktank, Machine man, and Chris. A really great writeup Machine Man.

In my first post I said that I had changed the condenser, but it was the receiver/drier I changed to 134A. I left the factory 92 condenser. Yesterday I did a side by side comparison of my 92 and the 93 system. The condenser, booster fan, hoses are identical. The receiver/drier has different configuration of ports, but the 93 is a factory 134A and mine is a aftermarket 134A. I don't know which orifice tube the 93 has.

When I did the conversion, my compressor had gone out and I knew it was probably time for the conversion since R12 had gotten somewhat rare and expensive. I installed a variable orifice tube, which is what the AC shop suggested. They specialized in older systems and oddly enough, in Volvo AC. I purchased a complete kit from them. They're out of Houston, but I don't remember the name.

I'm wondering if changing the orifice to a fixed tube with a colder rating might help?

Thanks!

Unless the PO had it replaced at one time, if you are not the Original owner of the car, the condensers are NOT the same.

I have a 91' and 93', and they are not the same.

They will fit in the same space, and take the hose connections the same, but they are not the same.

I have a my 91' and one I pulled from the PNP out of a 93, and they are definitely different.

Its your call, but you may want to revisit this one more time, just to be sure.

Matt
--
1989 - 245, 1990 - 245, 1991 - 245, and 1993 - 245

Hi Jim,

Thanks for the compliments to the posters on here. It is nice to know we helped.

In reading that you change out the receiver/dryer on your car, I would like for you to know, it is called and was really the accumulator/dryer next to the firewall. These two things make reference to two different types of systems.

A receiver is used to describe the unit that is installed on the liquid end and the high side of a certain system.
A accumulator is installed on the low side between evaporators and the compressors. It is used to help prevent non-vaporized droplets flooding back through the compressor valves.

The receiver name, in particular, is considered a tank. It is a tank designed in size to hold all of the refrigerant that put into system and some excess if necessary.
The excess would be possible if it were overcharged slightly.
On cars this used to happen more times than not. The earlier systems were more forgiving to novices.
The capillary tube used on inexpensive cooling devices and the orifice tube systems are not!
The charge has to be exactly balance for the pressures to flow the refrigerant.
Ambient temperatures changes on both hi & lo sides affects the efficiency of operation to the amount of heat transferred for energy used. Translation is the low side will usually be slightly higher as the temperature climbs and therefore should not be used for crucial heat load control.
Air conditioning is not considered crucial even though we may think it is! (:-)

The older systems that have Thermal Expansion valves do work better but are more expensive to manufacture just because of the TXV being more complex!
They work better as they are not affected as much by ambient temperature conditions. The control of flooding the evaporator is more exact to match the heat load demand.

Then on commercial units will have service valves so that the compressor can be used to "Pump Down" the system.
This means to push all of the refrigerant over to the condenser/receiver side. Done by closing certain valves you could keep it there while servicing. This means replacing the compressor or the TXV or even a low side dryer filter. These units are repairable without the loss of refrigerant or at least a minimal amount.
On the cars the brilliant bean counters started blowing off service valves years ago on everything with exception right on the compressors. Now today, with even a cheaper driving force, they are now too, gone away!
The big push was to sell mandatory "recovery machines" to create another market all together.
Truly a scam went on and as you can tell it made me sick, for the blame to go to the refrigeration trade for depleting the ozone.
It truly was packaging industry using blown styrofoam and the cleaning of electronic components, using refrigerants, that cause the issue. Now its Co2 and R-134a's Co2 footprint that's worse.
By the way R-134a in California is about $20 for a 12 oz. can. $10 deposit on each can! Scammers!
If you don't use a whole can, you're stuck! So, when I go out of state, you guessed it, interstate commerce or go on line! Same same!

Anyway back to your post not mine. (:-)
When you lost the compressor I assume it did not blow up or otherwise you would have had to clean out the condenser and at least checked the orifice tube for trash caught in the screens.
You have a variable orifice so do you still have the old one? Measure its inside diameter.

On the web AZone offers .057 and .072 fixed. I think you can use the .072 for R-134a. It probably takes more liquid to do the same job as R-12.
My idea is that the variable orifice can possibly help with the climate change conditions. Theoretically, it operates on pressure differences anyway.

Only kicker is it has to work! From what I have read they are not reliable or just don't work.

You either change the opening diameter or the length of the tube to vary the output.
As best I know these things works with a spring or springs to move with flow rate or pressure difference with cones or a tapered needle.
Any excess oil or one speck of trash and it becomes "fixed" or should I say, broken! The restriction cause the changes of state from hot liquid to large vaporous droplets, of which, need to reach almost to the tailpipe of the evaporator to absorb heat and flash off to gas only! The reason for the accumulator.

It's bad enough that screens can get clogged from a wax like substance that forms at low temperatures in the oil. Of course this happens rarely but with lots of age of the oil or moisture contamination, so take your pick. Car units are not hermetically sealed!
This is a reason why I like "high side receiver/dryers" as they stop trash from getting to the TXV.
The orifice tube is left wide open for that kind of failure.

You changed the dryer package with the accumulator as it comes that way. We used to, in the 70's, be able to take the accumulator a part from the bottom and change only the desiccant bag out.

Did you think the system had been open too long and it could be wet with moisture?

Did you open the compressor and see what caused its failure or did it just wear out and not pump?

I suggest you take pressure readings but on this car, thanks to bean counters again, is only the low side.
Look at it a determine where or if and how much liquid is in the accumulator. They do make sonic liquid detectors but I don't expect you to have one.
You will have to use thermometers placed along the suction line to find temperature difference from the tailpipe, base of the accumulator and the outlet line going back to the compressor.
There should be 5 degree to 10 degree jump between the three locations from either side of the gauge point pressure and the temperature scale. There is a lack of heat transfer through tubing. The pressure can be up to ten degrees colder that the actual tubing. Under Most conditions, I see five! Hoses can be very difficult to read. Sweating water or frost is the call here. No frost or near the compressor is best.
All this is Preferably, is more along on the return line to the compressor. You want to find if the gas is being superheated out from inside the accumulator to the compressor. That is the jump mentioned.

Now!
I don't expect you to do any of the above!
You have only the choice to change out the orifice and go with it.

I just wanted you to know, that the boys with white lab coats, nice testing conditions, have decided all of this for you!
The precise refrigerant charge is one of them. Set for average climates around the world that they ship into.
The charge and orifice maybe slightly different nearer the equator or in Alaska.
But at least you have some background and for what to look for!
Sweating or frosting, after the cabin is stabilized on that nearly too hot humid day.

On average it is a better system than those earlier Volvos.
They were woefully a bit too small, but you can tweak a TXV to do better, plus it has a cabin thermostat.

GM only advises 57 degrees to blow out of there. This is because getting out of a cold car and stepping into the heat can cause fainting due to thinner air.
Shopping malls are not allowed to over cool entrance areas for this reason. Let alone the expense!
This is not a TXV system!

Bye the way, to Chris, 34.(?) degrees out the center vents, IMHO is flirting with icing up the evaporator and possibly causing a flood back to the compressor. Especially on a long drive.

Remember the outside temperature changes during the day.
Driving changes the altitudes to the tune of about 3 degrees with every 1,000 feet of elevation.
The temperature control of the cabin is only by you and your fan speed.
The bean counters took away the thermostat or any kind off "real" deicing control monitor.
All you got is that pressure switch in the accumulator. If it sticks closed for a little longer, that it ever has before, you have no margins for errors.

That is not a liquid float sensor in there. It takes less than a tablespoon of liquid and it's like a rock to a piston. There is no squish space above the Pistons.
These Sandens have six or seven of them! Odds are worse than on the old compressors with only two behemoths that even used mufflers!

Keep cool, if you can.
I do, by not going where it's hot in the first place. Another benefit of being retired!

Phil

Whoa Phil,

Bravo, that's the kind of real world info I'm looking for! You are truly an AC guru.

Thanks BrickTank, I'll check the numbers on both to make sure.

The original R12 compressor just stopped compressing. When I installed the new system I did clean out the system to clear it of old oil and any debris. I can't remember what was recommended, but it seemed like a MAF type cleaner. I then blew out the lines with compressed air, connected the new parts, then pulled a vacuum for a couple hours. When I charged the system, it was a hot day. I ran the inside fan on full when I charged it. I don't remember how much freon it took, but it wouldn't take anymore. This was the process I was told to follow.

It has been consistent, but not the greatest on really hot humid days. I don't think it changed much since I first converted it in 2005. I remember there was about a 25F degree difference in duct temperature (stabilized temp) vs outside temperature which is what it still has. 85F outside, blows about 60F inside. On 95F days when driving in the sun, that's not nearly enough to keep up. It's blowing 80F plus. The evaporator has never frozen up as far as I can tell, no difference air duct speed. Maybe I'm a bit overcharged or the orifice problem?

I guess it's very possible some debris from my cleaning/etc clogged the orifice tube from the start. I have no idea what size it had originally. I can check the 93 to see what it has.

Thanks for the great info,
Jim

Phil & Jim,

Model year 91 and 92 were the same condenser size, and changed again in 93 to accommodate the change from R12 to R134a.

On a side note, this weekend, with the aid of a good friend of mine, we were able to get the a/c in my 1990 back up and running.

Though it was a cooler day here in Maryland, I recorded a new record (for me) coming out of the center vents, 34.3 degrees (F).

Good luck,

Matt

--
1989 - 245, 1990 - 245, 1991 - 245, and 1993 - 245

The condenser is what needs to be changed, not the evaporator.

That is where the difference is.

Change that out and you should be good to go.

Matt