My AC (converted r134a) was working last year after I charged it. Worked great for the whole summer.

This summer, it was running warm/slightly cool air so I checked and the low side indicated it was low. Tried to charge it but as soon as I put coolant in the system, it stops pulling the coolant in and the reading for the low side goes through the roof. When I unhook the quick connect it makes a hissing noise and when I hook back up and check the pressure, it's low again.

Any thoughts? Valve somewhere that's getting stuck? I'm stumped as to why the coolant can't get into the circulation.

Engine/AC pulley are both running.

Also noted was that the AC is fairly cold on fan settings 1-2, but when 3-4 are used it does not feel cool at all.

 

you might need to take it to someone who can pull a vacuum on the High and Low side before it can be recharged correctly. It almost sounds like there is too much freon in the low side, but this is a guess just something to look into to.

 

So someone looked it over, and apparently the compressor is bad. Ugh.

What's the next step? Get another compressor from a yard and go from there? Anyone gone through this and have some good ideas?

Thanks

 

I would probably try to get a refurbished one, I wouldnt trust getting one out of a junkyard but thats just my opinion.

 

Given the advanced age of our cars, unknown used compressors are a crap shoot I'm not willing to take. The only second hand compressor I would use would be off a car with which I was familiar. I'm buying one now from a fellow in Alabama who's 240 was picked up in a tornado and deposited in a ravine some 100 yards away...the car didn't make it but the compressor's fine! And...who can resist a compressor that has visited the Wizard of Oz?

 

I assume this would be the easiest time to completely convert the system to a r134. no?

 

[quote=zloetakoe;281420]I assume this would be the easiest time to completely convert the system to a r134. no?[/quote]


Depends on how cool you want to be. You lose 10-20% of your cooling capacity with a conversion. Also, unless you change your hoses to the new barrier hoses with an inner lining you will continue to lose refrigerant. R134 molecules are smaller than R12 and will seep through R12 hoses, which is why they had to change the design. The O rings are also different for 134, another leak source that needs replacing. R12 is a far superior refrigerant and it is still available, although fairly expensive. The greenies don't care if you sweat or not. If you change the hoses to the new type and recharge with R12 your system will be about as leakproof as you can make it. However, if you are convinced that you need to convert you should go with the official Volvo conversion kit; it takes more than 20 bucks worth of Interdynamics fittings from Auto Zone to do it right..

 

Well shoot Joseph, that sounds like a lot of work.

I wonder when this summer is going to cool off here in Philadelphia.

Is there any good r12 replacement? I've seen some stuff on ebay (r414), but you have to be EPA certified to buy it. Lame. Any easy way to get ahold of some freon that can be used in the old systems?

 

you should still be able to get it from any major service center, like a dealer or any other large auto shop.

 

Actually, don't count on it. After R12 was banned, existing supplies jumped through the roof on price. I can remember when one can was 79 cents. I've seen it reach $80 for a 12 ounce can after the ban. As time went on, the demand for R12 declined along with supplies keeping prices high. Today, demand is nearly non-existent. Several reasons...92 and older cars still on the road are declining, those on the road either have inoperable a/c because the owners can not afford to repair it or the a/c has been converted many years ago. The tiny percentage of cars still purposely running R12 almost qualify as a niche market. Recently, a fellow came by the shop and had two 30# tanks of R12. We bought them both for $400...basically the same price R134a sells for currently. We seldom use R12 in the shop...maybe once a year at most. We bought it solely because my brother-in-law and I both prefer it in our older cars. The fellow sold the stuff for so cheap because no one at any other shop he went to would buy it. So...R12 is going going gone. If you want to have a more efficient R12 system w/o the difficulty of obtaining R12...consider one of the hydrocarbon refrigerants such as DuraCool or MaxiCool.I've run it for over 18 months in my 140 w/o issue. Cools much better than R134a.

 

wait. zloetakoe said his car was converted to r134a already. i wonder if by 'complete the conversion' he was thinking of putting a larger expander in it? also adding an electric fan to cars that don't have one, and adding a relay to force the electric fan on when the ac is running will be a big help.

something else that can mess up a A/C charge is too much oil in the system.

 

I was answering Volvohaden's comment that...at the time I thought was saying R12 was still available at most shops.
To convert an 88 to the 93 only a/c set up involves replacing the entire heater case as the evaporator is larger in the 93. I had the aux fan wired to run w/ the a/c comp on my 245, the 740 and even my 140. Around town driving really benefits from the fan.
And, while JoesephTx is spot on as to what all is involved in completely retrofitting for R134a, it is indeed a lot of work and money to convert to a refrigerant that is going the same way as R12.

 

well, supposedly the next refrigerant drops right into R134a systems with no changes and has the same heat capacity and pressure range. H1234a or smoething.

 

sorry for the confusion. I was asking about the r12 because the other volvo I have (88 244) is NOT converted to r134. I asked a question about the r12 for that car.

Back the the 88 245 which was converted, funny thing happened. When I took it into the place to have it looked over, they said the compressor was bad, but before I took it in it was cooling decently on fan setting 1-2. I just figured it needed a charge and was hoping they could get that done with their equipment. I wasn't able to charge it myself as explained earlier.

NOW, after getting the car back from the shop it is blowing only HOT air on all settings, even though the compressor is still turning on. I'm wondering if they messed something up. They didn't charge us anything although they said they would when we brought it in for diagnostics. Could it be they dropped the charges because they know they screwed something up? Eh, in any case, why would the AC only be blowing HOT air know? It's much warmer than even the air outside. Could they have simply overcharged the system?

 

maybe your heater valve is stuck on?

 

If the compressor is bad or if it started to put parts in the freon you most likely have a plugged orifice valve. Just go on line and look up AC compressors. There are a lot of different places that sell new or rebuilt compressors. Just hunt around. I converted my 89 740 10 years ago and it blows 40* temps from the center vents. I had replaced all but 1 hose and I'll most likely do that in the fall only because that will complete the total system replacement.

 

my 90 740 gl has been retrofitted but unsure if it was done right. the previous owner said that he charged it randomly and it would work for awhile. Well I put 2 cans in it not sure size just Dupont cans we had at work one had dye in it so I could check for leaks, well its been about 3 weeks and it dosent seem to be cooling as good anymore, but also I cant seem to find any leaks. How do I know if it has been retrofitted correctly?

 

Quote:

Originally Posted by Volvohayden

my 90 740 gl has been retrofitted but unsure if it was done right. . Well I put 2 cans in it not sure size just Dupont cans we had at work one had dye in it so I could check for leaks, well its been about 3 weeks and it dosent seem to be cooling as good anymore, but also I cant seem to find any leaks. How do I know if it has been retrofitted correctly?

Most likely, you don't. When I got my 740 it had allegedly been "converted". First thing I did was convert it back.

I personally have no use for dyes. They displace oil/refrigerant, could conceivably clog something that doesn't need to be clogged, and most importantly, they only work if the leak is somewhere easily seen. What if your evaporator is leaking up under the dash? If you suspect a leak you can use soapy water to check the obvious leak spots and an electronic leak detector for the hard to find ones.

One thing to keep in mind: the amount of refrigerant to charge with when going to 134A is in most cases only 80% of the R12 amount.

 

So about how much r12 does it take to fill the system of the 240?

 

I did my 740 conversion years ago and if I were to do one today I would do a few extra steps. You need to remove the receiver/dryer , the orifice valve and the compressor. Buy a can of AC flush and flush out the hoses and evaporator and condenser. If I did this today I would replace all of the hoses. Then pressure or vacuum test the evaporator and condenser. I would replace the compressor with a new or rebuilt one. Put the system back together and pull a vacuum for 4 hours to remove water and flush chems. Also wire a relay into the low pressure switch on the receiver/dryer to turn on the front electric fan when you switch on the AC. Now charge the system until you get 30-40PSI on the low side and 45*in the center air duct. The whole deal takes about a day to do it right and you should have a as new AC system. I have not found 134 IN THIS CAR to be less effective then R12.