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  #1  
Old 07-15-2011, 09:14 AM
61Hawk 61Hawk is offline
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Larger A/C Condensor

I was complaining to someone yesterday about how my '89 GW's A/C doesn't cool much more than 20 degrees of the outside temperature when I'm in city traffic... if it's 90 degrees outside it'll blow 70 degree air, 100-80, etc. When I'm on the highway it'll blow air that's below 40 degrees. He asked me if I had the conversion to R-134A done, which I had. He then asked me if I had put in a larger condenser because R-134A isn't as efficient as R-12. I hadn't, so I got online and found that others have been told the same thing.

So, my question is if anyone has put a larger condenser after or during their R-134A conversion. And if they were able to notice any difference. I have thought about putting in a Contour electric fan to help pull air through the condenser. I'm guessing both would be the right solution, but was wondering of it was worth my time and money to just do the condenser.

Thanks,

Lee

Last edited by 61Hawk : 07-15-2011 at 09:29 AM.
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Old 07-15-2011, 08:42 PM
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jpcoutts jpcoutts is offline
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I think you must have some problem other than the condenser being too small. The a/c on an FSJ will generally blow ice cold when all the stock parts are working properly and the system is properly charged. If you're sure you have a fully charged system start looking for other issues. Does the temp control have any effect? Is air moving through the ducts, if not your evaporator coil could be freezing-up which is generally an indicator of compressor issues if you have a fully charged system. Overcharging the system will reduce its performance as well.
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Old 07-15-2011, 09:24 PM
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Sounds like you have low air flow across the condenser at idle. Replace your fan clutch with a heavy duty unit.

At 100* ambient temp, mine will blow 50-55* at idle and in the low 40's driving down the road. At 85* in the morning it will get into the low 30's. Mine is a 134a conversion with a stock system and two electric fans, one Ford Taurus on the radiator and one 16" aftermarket on the condenser that only comes on with the a/c.
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  #4  
Old 07-15-2011, 09:34 PM
deadironrat deadironrat is offline
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I am working on upgrading mine to a larger one right now. But since I am not complete I cannot report any results. You are correct that R134a is less efficient then R12, while some people have no problems after making the switch, some do. The general consensus here is that the stock condenser is adequate. The one I am upgrading to is a cross flow design like the newer cars use instead of the old tube and fin.

If you spend a little while searching you can find several articles where people have upgraded and had air temps around 5 degrees cooler then before the upgrade. If you think the time and money is worth it for 5 degrees then it's a worth while swap.

I have to agree with Jim, you probably have some other issue lurking if you vent temps are that high, you might need to clean your evaporator or replace you expansion valve. I'm no AC expert, just throwing easy cheap ideas out there.

P.S. I currently playing around with charging the AC system with propane instead of R134a, apparently in other countries this is a fairly common thing and people are reporting good results with it. At 3.27 for a bottle big enough to charge my system twice I'm willing to give it a shot.
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Old 07-15-2011, 09:56 PM
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247pia 247pia is offline
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Quote:
Originally Posted by deadironrat
I am working on upgrading mine to a larger one right now. But since I am not complete I cannot report any results. You are correct that R134a is less efficient then R12, while some people have no problems after making the switch, some do. The general consensus here is that the stock condenser is adequate. The one I am upgrading to is a cross flow design like the newer cars use instead of the old tube and fin.

If you spend a little while searching you can find several articles where people have upgraded and had air temps around 5 degrees cooler then before the upgrade. If you think the time and money is worth it for 5 degrees then it's a worth while swap.

I have to agree with Jim, you probably have some other issue lurking if you vent temps are that high, you might need to clean your evaporator or replace you expansion valve. I'm no AC expert, just throwing easy cheap ideas out there.

P.S. I currently playing around with charging the AC system with propane instead of R134a, apparently in other countries this is a fairly common thing and people are reporting good results with it. At 3.27 for a bottle big enough to charge my system twice I'm willing to give it a shot.

Cooling with propane has been around for a while the problem is if you have a leak you could blow up or get burned badly. Imagine your evaporator leaking, you light up a cig and you die.

R134 is not less efficient than R12 the problem is that at 35 psi R12 is at 35 degrees but R134 is at (don't remember exactly but you will get the point) 40 degrees. So most systems are set off of pressure, a pressure cycling switch controls the compressor shutting it off a 35 psi so now with the R134 you are at 40 degrees instead of the 35 you had with the R12, now there are two cures to this. One being if you have an adjustable pressure cycling switch you just turn the screw to lower the pressure while monitoring your gauges and vent temp. The second option is to replace the orifice tube with a Ford colored blue one as this has the diameter that will compensate for the change in pressure. Our Jeeps (I assume all, could be differences) use a thermal expansion valve or TXV to control our vent temps and this type of system is immune to the pressure differences as it works off of temperature. So though you benefit from a larger condenser that may not be the problem with your AC. Most of the time I find it easier to spend some time and diagnose the problem and fix it than trying a quick fix. As stated earlier it cools great going down the highway but no so good in traffic so think about what else is involved here. One final note R134 can take an overcharge better than R12, sometimes I have been able to get another 5 to 10 degrees lower vent temps by adding more 134 than what was required and the pressures rise was minimal if any.
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Old 07-15-2011, 10:04 PM
deadironrat deadironrat is offline
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Quote:
Originally Posted by 247pia
Cooling with propane has been around for a while the problem is if you have a leak you could blow up or get burned badly. Imagine your evaporator leaking, you light up a cig and you die.

R134 is not less efficient than R12 the problem is that at 35 psi R12 is at 35 degrees but R134 is at (don't remember exactly but you will get the point) 40 degrees. So most systems are set off of pressure, a pressure cycling switch controls the compressor shutting it off a 35 psi so now with the R134 you are at 40 degrees instead of the 35 you had with the R12, now there are two cures to this. One being if you have an adjustable pressure cycling switch you just turn the screw to lower the pressure while monitoring your gauges and vent temp. The second option is to replace the orifice tube with a Ford colored blue one as this has the diameter that will compensate for the change in pressure. Our Jeeps (I assume all, could be differences) use a thermal expansion valve or TXV to control our vent temps and this type of system is immune to the pressure differences as it works off of temperature. So though you benefit from a larger condenser that may not be the problem with your AC. Most of the time I find it easier to spend some time and diagnose the problem and fix it than trying a quick fix. As stated earlier it cools great going down the highway but no so good in traffic so think about what else is involved here. One final note R134 can take an overcharge better than R12, sometimes I have been able to get another 5 to 10 degrees lower vent temps by adding more 134 than what was required and the pressures rise was minimal if any.

I am also resolving the underlying issues. I replaced the compressor with another good unit, replaced my expansion valve with a new unit, and will also be flushing before I replace the condenser. I do know the risk of propane being explosive but from what I understand the amount that is inside an AC system is not enough to be able to ignite inside a car interior, plus I don't smoke

The main reasons I am going propane is of course price. But also because the pressures it operates properly at are far closer to that of R12 then R134a. I don't think my 32 year old York compressor likes those higher pressures very much. I'm not suggesting or recommending anyone else follow in my foot steps, all this changing with the AC system is just a little experiment for me.
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  #7  
Old 07-16-2011, 06:14 AM
Chumley360 Chumley360 is offline
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I'm just going to say what out if you install a larger condenser. When I fixed all my AC stuff on my 79 I used a universal that was a little bigger (14x25.75x.875) cause I couldn't find a new OE-style replacement and it was a really great price. Well it fit the hole and I got all my new lines run without any major issues. But the hook on the passenger side hood latch hits the upper line due to the extra height. So now my hood sits up a little on that side.
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  #8  
Old 07-16-2011, 09:55 AM
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Quote:
Originally Posted by 61Hawk
....So, my question is if anyone has put a larger condenser after or during their R-134A conversion. And if they were able to notice any difference.

Not what you want to hear....but I agree with others to fix what's not performing up to snuff first. I did the R-134a conversion several years ago (York compressor) and it performs very well, including standing still in traffic. You risk going through the time and expense to install a larger condenser only to find out that whatever the problem really is, is still afflicting you. If you have an air flow problem because of a worn fan clutch then you'll still not have adequate airflow. For the air flow volume involved through the grill and past the fan, it takes X airflow to carry away Y heat regardless of condenser size. On a one-to-one comparison, a larger condenser may cause gas condensation (or temp drop) quicker from the moment you turned the system on, but the ultimate temperature to which it drops would still be the same....because air flow (and therefore rate of heat exchange) is still the same.

But suppose I'm wrong and a larger condenser does improve the cooling. I intuitively believe it wouldn't be as much as you're hoping for, and you're likely masking a still-existing problem that will eventually fail altogether. (fan clutch, expansion valve, temp sensor, etc.)

I'm by no means the last word on this, but if condenser size was a real issue after R134a conversion, we'd have known it long ago and there'd be a standard answer. And I've to hear about it. Yet. (Anyone?)
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  #9  
Old 07-16-2011, 10:49 AM
61Hawk 61Hawk is offline
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Thanks for all of the responses, I do believe it has to do with air flow more than the system not working. I can drive from work to home (11 miles) in stop and go traffic and the vent temp is 20 degrees below outside air temperature. If I get above 45 mph I can watch the vent temp drop. If I get out on the highway the vent temp will run 35-40 degrees.

I checked out the original condenser last night and it was larger than I expected it to be, I don't know if I could fit a larger one in there if I wanted to... I could probably get a better flowing one.

I think my options at this point point to either a heavy duty fan clutch or to go with the Ford Contour electric fan conversion.
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Old 07-16-2011, 10:52 AM
61Hawk 61Hawk is offline
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Quote:
Originally Posted by Chevelleguy
Sounds like you have low air flow across the condenser at idle. Replace your fan clutch with a heavy duty unit.

At 100* ambient temp, mine will blow 50-55* at idle and in the low 40's driving down the road. At 85* in the morning it will get into the low 30's. Mine is a 134a conversion with a stock system and two electric fans, one Ford Taurus on the radiator and one 16" aftermarket on the condenser that only comes on with the a/c.

Wow... no lack of air flow there.
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  #11  
Old 07-16-2011, 01:21 PM
61Hawk 61Hawk is offline
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Okay went down and bought the Hayden 2797 heavy-duty fan clutch and got it on. Now to wait until the battery charges so I can start it... it's been sitting for a while because of the heat.
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Old 07-16-2011, 02:04 PM
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247pia 247pia is offline
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Quote:
Originally Posted by 61Hawk
Okay went down and bought the Hayden 2797 heavy-duty fan clutch and got it on. Now to wait until the battery charges so I can start it... it's been sitting for a while because of the heat.

Did you check to see if your fan was pulling air before you bought that?
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Old 07-16-2011, 02:12 PM
61Hawk 61Hawk is offline
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Test drive - 89 degrees outside with 42% humidity.

City driving - 25-45 mph, stop and go traffic. Blower fan on high... vent temp 65-66 degrees. Blower fan on 2nd lowest... 60-61 degrees.

Highway driving - 65-70 mph. Blower fan on any speed setting, vent temp 35-37 degrees.

Last edited by 61Hawk : 07-16-2011 at 02:15 PM.
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Old 07-16-2011, 02:13 PM
61Hawk 61Hawk is offline
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Quote:
Originally Posted by 247pia
Did you check to see if your fan was pulling air before you bought that?

Yes it was, fan had the factory original fan clutch. Truck has 77,000 original miles on it.
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Old 07-16-2011, 02:14 PM
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247pia 247pia is offline
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Quote:
Originally Posted by 61Hawk
Test drive - 89 degrees outside with 42% humidity.

City driving - 25-45 mph. Blower fan on high... vent temp 65-66 degrees. Blower fan on 2nd lowest... 60-61 degrees.

Highway driving - 65-70 mph. Blower fan on any speed setting, vent temp 35-37 degrees.

Not your blower, your cooling fan. Okay I see you responded. So is this after the clutch fan replacement?
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Old 07-16-2011, 02:26 PM
61Hawk 61Hawk is offline
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Quote:
Originally Posted by 247pia
Not your blower, your cooling fan. Okay I see you responded. So is this after the clutch fan replacement?

Yes.
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Old 07-16-2011, 02:30 PM
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247pia 247pia is offline
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Quote:
Originally Posted by 61Hawk
Test drive - 89 degrees outside with 42% humidity.

City driving - 25-45 mph, stop and go traffic. Blower fan on high... vent temp 65-66 degrees. Blower fan on 2nd lowest... 60-61 degrees.

Highway driving - 65-70 mph. Blower fan on any speed setting, vent temp 35-37 degrees.

You are low on refrigerant.
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Old 07-16-2011, 02:51 PM
61Hawk 61Hawk is offline
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I've never added freon to an older style system like this, all I have is one of those gauges you screw to a can and connect it to the low side. Do I need to open the screw in valve on the low side? If I leave it as is and open the can the gauge goes right to high so I'm guessing that the valve is closed and nothing is being added past the hose. Just don't want to screw this up by adding too much.
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Old 07-16-2011, 03:01 PM
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Quote:
Originally Posted by 61Hawk
I've never added freon to an older style system like this, all I have is one of those gauges you screw to a can and connect it to the low side. Do I need to open the screw in valve on the low side? If I leave it as is and open the can the gauge goes right to high so I'm guessing that the valve is closed and nothing is being added past the hose. Just don't want to screw this up by adding too much.

Open valve and let er suck!
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Old 07-16-2011, 03:21 PM
61Hawk 61Hawk is offline
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Opened the valve, hooked up the hose, started the GW and turned on the A/C. Gauge is reading right in the middle of the "Filled" section.

But... now my water pump is leaking...
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