dbarton
Dejected by Volvo Corp.
- Joined
- Nov 17, 2002
- Location
- Prosper, TX
I would like to start a discussion on using propane (or other hydrocarbons) in Volvo AC systems. I suspect using hydrocarbons violates some environmental laws, so for the purpose of this discussion, any practical use mentioned here is simply hypothetical.
First, some Volvo green book info:
I was told by a friend who has some experience with propane that it is easy to overcharge, so you should use only about 1/2 of the amount of R134a needed. It seems propane is a much better refrigerant than R134a or R12 and it has a tendency to freeze valves closed if too much is used.
MY SITUATION:
In my hypothetical situation, the car is an '84 240T, original condenser and evaporator, new R134a rotary compressor and hoses a few years ago, and recent new receiver/drier and expansion valve. Previous R134a charges have resulted in cool vent temps (50s), never very cold, and lousy performance when ambient is 90 F plus.
So far it appears using as little as only 6 oz of propane is too much and causes things to freeze up after about 20 min. I suspect the freeze-up is in the expansion valve area. Symptoms are a gradual rise in vent temps, eventually to ambient. Low side pressure gradually drops (begins about 25-30) to ZERO, while high-side remains between 150-180. It begins working ok again after letting the car sit (thaw out) for 4 to 8 hours.
When it works, I get vent temps in the mid 30s F (ambient 80 F). I have tried a number of different amounts beginning with 12 oz and working downward. I use a postal scale to measure the bottle before and after, and lately during the charge. Each recharge gets a new vacuum for 20-30 minutes. Results are the same in all attempts. If there's any moisture in the system, it could only be coming from the propane (is that likely?).
Dave B
UPDATE 2012: I decided to change to Duracool as an R12 replacement instead of straight propane. Cooling had been ok for cruising with propane, however there were some periodic issues with freeze-ups and problems cooling during idle.
UPDATE 2017: I decided to abandon the original Volvo evaporator box in favor of a completely new system from Classic Auto Air. I have posted all the details of that conversion at: http://www.240turbo.com/volvo240mods.html#classicair
First, some Volvo green book info:
Coolant Capacity
240 R12 systems 1979-1990 2.86 lbs
240 R12 systems 1991-1992 2.42 lbs
240 R134a systems 1993 1.65 lbs
Performance Testing (measured at center vents)
. . . . . . . . . . . . . . . Ambient 68 F . . Ambient 86 F . . Ambient 104 F
240 1979-1990 . . . . . 46.4-50 F . . . . 48.2-53.6 F . . . 48.2-53.6 F
240 1991-1993 . . . . . 41-46.4 F . . . . 41-46.4 F . . . . . 46.4-53.6 F
Above tests with hood closed, engine 2000 rpm, AC set to "Cool", fan speed at 3, recirc set on.
I was told by a friend who has some experience with propane that it is easy to overcharge, so you should use only about 1/2 of the amount of R134a needed. It seems propane is a much better refrigerant than R134a or R12 and it has a tendency to freeze valves closed if too much is used.
MY SITUATION:
In my hypothetical situation, the car is an '84 240T, original condenser and evaporator, new R134a rotary compressor and hoses a few years ago, and recent new receiver/drier and expansion valve. Previous R134a charges have resulted in cool vent temps (50s), never very cold, and lousy performance when ambient is 90 F plus.
So far it appears using as little as only 6 oz of propane is too much and causes things to freeze up after about 20 min. I suspect the freeze-up is in the expansion valve area. Symptoms are a gradual rise in vent temps, eventually to ambient. Low side pressure gradually drops (begins about 25-30) to ZERO, while high-side remains between 150-180. It begins working ok again after letting the car sit (thaw out) for 4 to 8 hours.
When it works, I get vent temps in the mid 30s F (ambient 80 F). I have tried a number of different amounts beginning with 12 oz and working downward. I use a postal scale to measure the bottle before and after, and lately during the charge. Each recharge gets a new vacuum for 20-30 minutes. Results are the same in all attempts. If there's any moisture in the system, it could only be coming from the propane (is that likely?).
Dave B
UPDATE 2012: I decided to change to Duracool as an R12 replacement instead of straight propane. Cooling had been ok for cruising with propane, however there were some periodic issues with freeze-ups and problems cooling during idle.
UPDATE 2017: I decided to abandon the original Volvo evaporator box in favor of a completely new system from Classic Auto Air. I have posted all the details of that conversion at: http://www.240turbo.com/volvo240mods.html#classicair
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