I tackled this job early last summer and although not mentally taxing, it is a long job, and you must take care to keep everything clean.

My original system had developed a slow leak, which required that I add one or two cans or R-12 every other summer.

I had bought 3 cases (12 cans each) of R-12 (At $12 a case) back in college, when I heard that the gov't was going to implement a $4 per can tax on R-12. I had exhausted my supply on my various cars, so it was time to make a judgment call.

The factory system was never great (It doesn't get as hot in Sweden as it gets in Texas!), and when the temperature got over 98 or so, it was just cool and not cold. I made sure that I pressure washed the a/c condenser on the front of the car every few months just to make sure that there was good air flow, and in addition, about 15 years ago, I added an electric pusher fan to the front of the a/c condenser.

I usually stay with original Volvo parts, however, for this job, I decided to go with parts from FCP Groton.

I ordered an expansion valve, a receiver drier and the o-ring kit.

The Volvo dealership recommends replacing the expansion valve whenever working on the system.

You must replace the drier when the system is opened. When you replace it, be sure you do it quickly, so that the drier doesn't soak up too much moisture. Also, the FCP unit does have a sight glass, just scrape off the black paint...

As far as the o-ring kit, it's up to over $32 now, and considering you only use 10 or so of the 0-rings, if I had to do it over again, and I had access to a really good source of o-rings, where I could by them individually, I would just label the old ones as I took them out of the a/c system and would then go to the parts store and buy them separately. Would save a lot of money, however, you can save time by buying the o-ring kit...

I took apart my entire system, and used Interdynamics Auto a/c Flush and Clean to remove all of the old oil. I bought this product at Pep Boys and still have half of the 32 oz container. I ran this through the condenser, hoses and compressor. I then poured some Castrol Ester Synthetic 134a Oil as a "Chaser", to clean out the Flush and Clean.

I used my compressed air nozzle to clear out the lines. I know you said that you don't have compressed air, however, you might want to invest in this, it really comes in handy.

I removed the compressor from my car and drained all of the old oil from the unit. I poured the Flush and Clean into it, drained it, then added the Ester Synthetic 134a Oil. I did this twice. I then soaked my new green 0-rings in the oil and then reattached the compressor hoses back into place.

I also took this time to replace the rubber mounting bushings for my a/c compressor. In addition, I also used a strap wrench to hold the compressor in place and then tightened the mounting bolts, so that the compressor belt was on tightly AND on nice and square.

As you are probably aware, it is extremely difficult to tighten the a/c belt and have it on there squarely.

I don't believe it is necessary to have the a/c condenser replaced. I just cleaned mine and it is still working great.

I replaced the receiver drier and the o-rings.

Finally, under the dash I replaced the expansion valve and the o-rings there also.

I bought Central Pneumatic's Air Vacuum Pump for $11 at Harbor Freight, and also a US General a/c Manifold Gauge Set for $39.

I used my compressor to draw down a vacuum and let it sit for 30 minutes.

I only took a few minutes to draw the vacuum and it held, so I charged the system.

I bought 12 cans of R134a at Sam's club for $28.

I added the correct amount of R134-a, I think it is the same amount of R-12, (I believe 40 ounces) less 10%, so about 36 ounces or so. (Maybe it's 48 ounces, less 10%, so 43 ounces, be sure to check your car for an a/c label that lists the amount of Freon in the system!!)

I was amazed at the results! The air was blowing out of my vents at 25 degrees!

It was never that cold with the R-12, usually 40-46 degrees on a good day, and when it was 100+ in Dallas, Texas, the best I could hope for was 60-70 degrees.

I have had to add one can of freon since last summer, and over the weekend, I replaced my a/c blower motor, which died on me a few months ago, and I looked in the sight glass on the drier, and saw bubbles, so I know that I will need to add another can of freon to bring it back to its peak performance.

I understand that it is not unusual to lose some of the 134a, as the molecules are smaller than the R134a.

I hope this information has helped you.
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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 287K looking forward to 300K badge (I'm Almost There!!!)(or sticker??). >>You haven't really worked on a car until you draw blood<< :-}

Dont go toR134! A r12a(hydrocarbon)is compatible with r12 involves no changes(i would put a new receiver dryer just to start clean)is more efficient than r134a, less corrosive,less leaks,enviromentaly friendly.I dont get why people even still use 134a!
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Rene

FYI the "muffler" is the potato-sized assembly installed inline on the AC line leading to the condenser.

Read about my 87 245 total conversion here.

kourt
87 245
austin, tx

Long list,

Evaporator, does not have to be replaced, the R134 is supposed to have a larger capacity and cool better. Same thing applies to the condenser coils by the way.

O Ring kits will have lots of extra o rings, you can take everything apart and go down to a parts store and buy the sizes you need. The ScanTech kit is actually pretty decent, you will end up with several sizes left over.

Expansion Valves are cheap, not hard to replace, and that is one of those things you really need to do. There is an R134 expansion Valve and that is one of the the four things you should really do to make this successful. This is the same one used in Saab's and Porsche's by the way.

Dryer has to be replaced, goes on last, and is not expensive. Be sure to use new o rings. After market will work just fine if the fittings are all the same.

PAG 40, if you are going to open up the system, drain the compressor, replace the expansion valve, you are cleaning the lines away from being able to use it. If you open the system up that far and don't use a cleaner on the lines, you may wish you had. Key here is to remove the compressor lines and aim them at the ground. Remove the dryer and aim those lines down, and last but not least remove the expansion valve. You use the two lines inside the car to spray in the cleaner and then use plenty of compressed air to blow the gunk and junk out of the lines. The only line outside you need to clean with the system open is the line from the compressor through the evaporator to the dryer.

Fittings get new O Rings and use mineral oil to lube them up. The R134 fittings screw into the compressor, the low side on my 86 model is a PITA to reach since it is so close the frame rail. Going to put a 90 degree adapter in to make this easier to reach soon. You install new oil (Pag or Mineral don't mix them) minus 1 Oz for the dryer and after replacing the o rings install the lines back on the compressor. Install the Expansion Valve next use mineral oil on the new o rings. Install the low pressure switch on the dryer, add 1 oz of oil, lube up the new o rings and get the system sealed up so your dryer does not suck up all that moisture.

As far as pulling the vacuum, you can "Borrow" a compressor with the hoses and fittings from one of the Chain Parts house. You will want to have a set of gauges most likely. Harbor Freight has a decent set for less than $50 most of the time.

Lots of work but the resulting cool is really worth it.

Regards,

Paul

What I can't answer is the evaporator question. The '91 and newer models use the improved unit, but I believe it is a job and a half to change.

No easy way to remove the compressor... just get under the car and figure it out. You do have to remove it to get the old oil out and to change fittings. Take advantage of the opportunity to put in new mount bushings, and new drive belts as well.

The full retrofit kit from Volvo is worth it; you get all the O-ring seals you need, plus a new drier plus new hoses. Buy cheap, buy twice. I got my official Volvo kit from FCP (but again, I have a '91). I would look at the drier connections on a '91 or newer model to see if/how they differ from your model. My guess - *only* a guess - is that they are similar. Be sure before you invest.

I suspect what you call the "muffler" is the drier. Sorta like a large tin can mounted on the firewall. If you live in a humid climate (which is anywhere outside the SW desert) you should replace the drier when you open up the system for more than 5 minutes. Refrigerants are highly hygroscopic and water vapor compromises their performance. They are a replacement unit, like the other filters on your car.

With the hoses off, flush the old components out (evap + condensor). You can get spray cans of the stuff from any auto supply store. What's helpful is a shop compressor to blow the lines clear after the flushing agent is used.

I'm not sure if your Volvos has an expansion valve or an orifice tube. If the latter, replacements are about $3 from an automotive AC supplier. I would look at AC components listed by an auto AC specialty house to be certain - a generalist like FCP is probably not the defintive source of detailed info like that.

If you do luck out and your system uses an orifice tube, I recommend the variable orifice (VOV) if you drive in stop-and-go traffic. About $25 from the AC suppliers. Even if you opt for the conventional one, put a new one in. These are effectively a trap for gunk in the refrigerant system. And look closely at the old one you pull out... if it's loaded with black crud, that's a tipoff that you probably need a new compressor (and a serious flush of the rest of the system).

If your system uses the expansion valve, you might get away with re-using the old one, but recognize that these are a common problem source even on stationary AC systems. Yours is 20 years old.

Every O-ring in every joint in the system should be replaced. These are all under the hood, and come in the retrofit kit. Lube each with just a smear of the proper system oil before installing; this will help prevent tearing. If you run short, you can get replacements at the local auto supply place but you'll pay $12.50 for an assortment that has 20 rings you'll never need.

The changeover is conceptually simple, but as with so many things the devil is in the details. Go slowly, do it right.

I also have 240 1990. I tried the retro fit. It didnt work for me. To many problems. Perhaps I didnt do it right. I dont know.
Im back with R12. Had my system repaired. Put on new compressor(0ld one shot). Added a condensor fan. Im very happy with my system now. Been trouble free(third summer). Its working like new.
R134 was nothing but trouble for me.
Others here might have different experience. But thats my story and Im sticking to it. A system designed for R12 will have its best, trouble free operation with R12. Have the work done by a professional. System will be efficient, and leak free.

Its your car, your choice. I just wanted to add my two cent worth.

Good luck. Whatever you do, I hope you have icicles hanging from the ceiling In july/august.