The 86 245 pictured to the right of this post recently suffered from a locked compressor during a return trip from Florida which caused a broken belt and rendered the power steering useless. Since I have a pretty good supply of spare parts, I replaced the compressor with one off of an 88 744 and went in search of a vacuum pump so a recharge could be done. After driving around Charlotte in an unsuccessful try to buy a pump, I ran into an older fellow (about my age, 60 or so!) that told me the R134a systems did not need to be evacuated prior to filling as did the R12 systems. (The vacuum is to boil off any moisture in the system prior to charging). I invested in a couple of cans of R134a and a can of oil and charged the system myself. Voila, cold air is back in the vents just in time for summer weather!

I realize that most folks are scared to death to mess with the AC, but the R134a is sold over the counter because it is not a threat to the environment so if you leak a little out the green police won't be beating your door down.

Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles

Was the compressor throwing belts even when the A/C was not on? If this is true I would bet that your original R12 compressor is fine and that you only have a bad clutch/pulley on the front. A new clutch can be had from the usual suspects for around $100. I mainly want to point this out because I went through the painful experience of replacing most of the A/C components unnecessarily.

If you did not change the oil in the compressor and evacuate the system you probably already trashed your replacement compressor as others have stated. I would rebuild your original compressor and refill it with the correct oil. I also think that a seal kit is required on the older compressors to make them compatible with R134A. You also certainly need a new expansion valve and new O-Rings in the system because R134A has different operating pressures than R12 and it will attack the original O-Rings and cause them to swell.


Mike

The compressor broke and seized the belt while on the road. It is not rebuildable, and I have several good units on hand. I will pull the clutch for future repairs.
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles

"After driving around Charlotte in an unsuccessful try to buy a pump, I ran into an older fellow (about my age, 60 or so!) that told me the R134a systems did not need to be evacuated prior to filling as did the R12 systems."

Sorry- never heard of this one- sounds like BS to me. How else will you accurately measure your charge?

The only way to know how much refrigerant is in your system is to completely evacuate it first, then add a measured charge.

I vacuumed my system for an hour with one of those venturi-type pumps after installing the Volvo 134a conversion kit and it worked well- blows 36 degrees at the vent at ambient temp of 80F.

However, if your system works- and your compressor does not die, no worrys.
--
'92 240 wagon, 285k, '90 240 sedan 229k

Good web page on AC recharge.

www.aa1car.com/library/ac_recharging.htm

Hate to tell you, but if you didn't remove the compressor and drain the oil out, and refill with Ester oil, your compressor is doomed to a very short life, like a week or two. R134 is NOT compatible with the old oil in your system. Also, pulling a vacuum IS necessary. To properly switch to R134a, you must... 1. pull compressor and refill with Ester oil (compatible with R134 AND the old oil and traces of R12 that is left in the system, VERY IMPORTANT!) 2. replace receiver/dryer 3. replace orifice tube or expansion valve if clogged 3. some cars need to use a POA valve calibrated for R134 and not R12 if you want maximum cooling (haven't seen one on the 240, but I haven't gone there yet on my car) 4. you should flush the hoses, condensor and evaporator with A/C flush and compressed air to get as much of the old oil and trash out (especially if your car previously suffered "Black Death" or a failed compressor) 5. replace 0-rings as necessary and switches as necessary. 6. add R134 fittings 7. pull a vacuum for 50 min. and recharge with R134. Minimum for a long lasting A/C system and I'm probably forgetting something. I'm afraid your system won't last long, the way you did it, but I am not surprised at all that it is cooling now. Sorry, it ain't that easy.
Charles

On my previous car, an 88 745, I did a quick and dirty 134a conversion, using a kit. When I got the car, it had a bad AC clutch, which I replaced without opening the system, and a residual amount of R12 in the system, which was not sufficient to let the compressor engage. I took it to a garage, and had them remove the R12 and vacuum it for approximately one hour. I then drove it home, and immediately installed the kit, which consisted of an adaptor for the low-pressure port on the receiver-drier, and three cans of 134a with ester oil in it (note that it is ABSOLUTELY ESSENTIAL that any R12->R134a conversion use ester oil, and not PAG, which will ruin the system very quickly) and a charging hose witha gauge on it. After the second can had gone in, the compressor started cycling normally, and it was blowing nice and cold by the end of the third can (as it turned out, the amount of 134a required was exactly those three cans---there is a conversion factor based on the amount of R12 originally required) I used it quite a bit that summer (I live in Virginia, where it can get pretty hot for four or five months of the year) and by the end of the season it seemed to be getting a bit weak (cool, not cold) A brief shot of refrigerant restored normal operation. The following spring, despite having been run occasionally during the winter, it was weak again. I examined all the connections, and found a couple that looked slightly oily, tightened them, and gave it another shot of 134a (less than 1/4 can) and it was good all that year. Sadly, I wrecked the car last January, so I don't really know how much longer the A/C might have lasted, but when I dismantled it, the system was nice and clean inside, with light gold colored oil---no trace of the so-called "black death"---so I suspect it would have held up a good while longer.

To sum up, I believe what I did was the absolute minimum necessary for a 134a conversion, and I could have probably achieved slightly better performance, and improved durability and total freedom from leaks if I had done the whole nine yards, but all in all, I found what I did to give a satisfactory result.

hello Will
thats one way to do it, probably not the best.
down here in south fla in the summer that doesnt seem to cut it.
always vacume ac system when open, it is said. i have opened a system and plugged the lines for a short period without vacume.
the best system i have had in a 240 was flushed very carefully and vacumed.
also it is said the different oils do not get along and the compressor will not last as long.
what i do know is its going to get hot and soon down here.
take care
mike

Hi Mike,

I probably should have mentioned that the system in this car was completely overhauled three years ago with new components, and I opened it for the duration of the time for the compressor change. It has always been R134a and had no leaks. The purpose of pulling a vacuum on a system is to boil any solvents or moisture out at low temperature based on the vapor pressure of the solvents or moisture at pressures below atmosphere. Leak rate back to atmoshpere determines whether the system leaks or not. We use the same principles on the molecular distillation equipment that I build and run for separating chemical streams at pressures down to .006 mbar. This unit had no solvents or moisture, and I had to do a quick turn around on the 245 because it was headed for Western Kentucky the day after so there was not time to find a pump to evacuate the system. The AC performs well though and, if it goes again in three years or next year, I will probably fix it the same way. Besides, posting occasional poor boy fixes really seems to inflame some of these elitests which is almost as much fun as sticking a broom straw up a horse fly's butt.

Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles

Just don't mislead people to think that they can just throw R134 into an R12 system with no knowledge of what REALLY needs to be done. That's just not nice. I could care less about what you do with your car because you probably know what you are doing (I hope), but you could cost many people a trashed A/C system if you do not tell the complete story of EXACTLY what you did and why it worked. You may know what you are doing, many do not. Anyone can make a car A/C system cool, the question is... for how long before compressor damage and the need to go through it all to fix the damage. Doing it right is not elitest and poor boy fixes when done with the right know how CAN result in both money saved and a reliable car. IMHO
Charles

Hello Charles,

I absolutely agree with you that any repairs to an R12 system are beyond the scope of the average car owner, largely due to the fact that R12 is a real burden to the environment when it is released to atmosphere. Conversion to R134a is another animal altogether and is well within the scope of the average backyard mechanic. Part of the purpose of this site is to help those less fortunate when it comes to mechanical skills keep their Volvos on the road without a visit to the high dollar repair shops which most certainly include AC repair facilities that have kept prices inflated for years. If you have knowledge that would help the unenlightened, then I suggest you share your insight in a treatise designed to educate the rest of us in AC repair or whatever your field of expertise might cover.

Kindest Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles

Hello Dallas,

What you are saying is going to draw varied opposing views. Here is my two cents, if you have a system that is open (meaning no freon in the system at all from a leak) you really need to change the dryer and completely evacuate the system before you add coolant. If for no other reason to check for leaks, but I also think that your method will work on a system that had a charge before it was pulled down and opened up to be worked on.

I have in fact done that a time or two when just fixing a leak or say changing out an expansion valve. Getting some corks and plugging up open lines while the system is open and changing out the dryer is really a good idea. Excess moisture will lower your systems performance and having a leak and loosing all your coolant is a bummer when you miss a leak. A vacuum will catch a leak and get moisture out. With that said I agree the tried and true "redneck" vacuum procedure of jumping the low pressure switch and dumping in a can of freon, Followed by filling slowly until the pressures are good does works quite well. You may not be all that happy with R134 by the way, in hot weather in a 245 you system will fall behind.

If you find it to be not as cooling as you like later this summer as the sun starts beating down harder and thermometer and hydrometer both head for the mid 90's. You might want to consider a couple of BB Mods that really help out on a Wagon. This is assuming of course you have not done them yet. And tossing in one observation that may or may not be valid at the end about converted systems.

On a warm sunny day, stick your hand up over your head and push that liner up to the roof and fell the roof temperature. All you need to do to fix that is to pull back the headliner and add Reflectix Insulation. Did that this last year after reading up on the BB and it really works. Got mine down at the home center on the insulation isle. It looks like silver bubble wrap and I just cut it to the width between the cross braces and slid it in there. Used the recommended 3M 77 Adhesive on the top side, pressed it to the roof and it is still up there. Give that BB Mod two thumbs way the heck up.

Adding 28% tint down the side windows helps also, wagons have a bit more cubic feet of glass to let heat in and area to cool down. We can do full black on the side and back windows here in Texas. But I do not like that at night, too dark for old eyes. So I had 28% installed down all the side windows. That helps keep out a lot of radiated heat.

The BB mod that really helped was adding a pusher fan in front of the evaporator coil. Fans were added the last three or four years of production of the 240. I added a ebay purchased one from off a 93 last year and tied it into the green wire on the compressor that pulls in the solenoid. The BB sent me the instructiona on how to install it and I added some home brew wiring to add a relay. Took a couple of hours to install and to do the wiring. The compressor kicks on and a relay turns the fan on. That extra air moving over the coils makes a pretty big difference in performance at temps in the 90's at idle and low speeds.

And last but not least if you find the system falling off in performance check the pressures. Seems to me that the converted systems tend to clog up the expansion valve after a while. Could just be age, but have had that issue on my 86 and with a car I helped out with for a lady at the church. She could not afford to get the car fixed and the church provided the money and a couple of us fixed it up. That one clogged up in just a couple of months after it was converted. The one in my car took 1 year after conversion to stop up. All you have to do is pull down the system and replace the valve. Charge it up and you are good go.

Good Luck,

Paul

I have an 89 240 that I just bought and the AC is not working. The compressor does seem to work, just no cold air coming from the vents. Any tips on doing the recharge?

Thanks!!!!

To be sure what is going on you need a set of gauges. The compressor is running and no cold air our of the vents, that could be a clogged expansion valve, a low system, a bad low pressure switch and so on. The gauges will tell you what is going on and what to do next. By the way, connect with the engine off, and the high side should read low, and the low side should read high on a working system. Only when you start the car and turn on the compressor should the levels swap.

Here are what the reading mean most of the time:

High Low side and low high side, clogged expansion valve or blocked condenser coil

High low side and High High side- too much coolant

Low Low, Low High - Add coolant or bad compressor.

Those readings are your guide to getting your cool back on. Do Not fall for that single hose with a low pressure gauge on it. You need to see the high side when you do this.

By the way clogged expansion valves are very common on older 240's. Less that $30 part and a couple of hours to install.

There are couple of tricks to check if the compressor will come on and run. You can take the connectors that go to the low pressure switch off but that means digging around in there. You just take a short wire with two spade lugs and pull the connectors off the low pressure switch. Then you add the spade jumper and that will bypass and the compressor should click on and start running when you start the car. You do not want to touch chassis, there is 12 volts on that.

This will tell you for sure the compressor pulls in or not. Have someone start the car and watch the front of the compressor, and you should hear the click and see the clutch slide back and the compressor should start growling. Take the jumper out and put the wires back, you do not want to leave it like that.

Post back your results and we can guide you to what to check next.

Regards,

Paul

Good Luck,

Paul

Just wondering if there is an easy tell tale sign that lets me know I have the R134A. Before I bought my car 4-5 years ago the past owner (wealthy man using it just for a long commute over 2 western states) had the airconditioning compressor replaced. My switch on the console went bad since and I didn't notice it was constantly on for a while. If I replaced the switch it would be nice to fill up the compressor too. Thanks.

That one is easy,

The R134 Gauges will not fit on a R12 System. The connections have been changed so you in theory can not not accidentally connect R12 to a R134 System and vice versa.

If it was converted correctly you should also see stickers about the system being converted.

If you do have R12 and the system is only a little low on Freon, get that sucker charged back up. R12 is $36 for 12 Oz and that should get a low system back up to full power normally. You will need a pro to do that or a buddy with a license and a set of gauges.

But that one is a no brainier, R12 blows R134 away. There is no comparison at all. If you do have a buddy with a set of gauges and a license and do not want to pay for R12, get Freeze 12 and I can give you the upside and downside to both later.

Regards,

Paul