I have a 90 f150 with a r134a conversion and I am not happy with the result. This is the third vehicle I have owned with the conversion and none have cooled well. Two were done at shops and the other I retrofitted. I see Mr. Quintin's solution is to add a larger condensor which I have not seen. They all cooled OK except during the summer months especially in the 90+ degree heat, when it is cooler just to roll the windows down. I have a couple questions.

Anyone have experience with the propane based coolent and does it work better than 134a?

Would the addition of an electric fan give a marked improvement in performance?

Anyone have a link so to find a larger condensor? I refuse to get fleeced by a the local service centers again.

I plan to try the other coolent unless I get a red flag from someone.I understand it is flamable however an ac system is void of O2 so that doesnt worry me. I'm concerned that it's just a ploy for a buck.

Thanks for any input

Brian

 

I did a retrofit and used 134a, to a van which I later sold. A/C was OK until it was very hot, and then it didn't work well. The last retrofits that I did I used Freeze 12, it was better than 134a.

If I was going to do the job of properly evaculting the system, (epa compliant), then flushing out the oil, and changing over to one of the other Freon substitutes (their oil is not compatiable with the 134a oil, but works with the oil used in the Freon systems), I would pay the extra cost and locate some Freon. Unfortunately nothing works as well as Freon in an older system. Most people with older cars using 134a or a replacement gas are not satisfied with the results.

There is a test you can take online for an EPA certification which will allow you to buy Freon in small containers (the test is about $15-$20 I think). There is still Freon floating around, do a search on Ebay. Again if you plan on keeping the vehicle, and don't mind spending the extra $ that is the way to go. The Freon replacements work OK, but nothing is as good as R12.


Frank D

 

I can't justify paying for R12, just to have to buy it again in a year or so when another ac part fails on this old truck. It's just too risky. So I am back to a change in refrigerant type or a new condenser. I find many people who say a larger condenser will work however I can not find anyone who offers and upgraded condenser. Everyone seems to agree 134a is basically worthless with R12 hardware but only the oddball refrigerant companies offer solutions. Can anyone educate me on a condenser upgrade i.e. Will one be sufficient from a 95 or newer ford truck? Can I go too large? Can I double them up? Suggestions?

B

 

I use Freeze 12 I all of my R-12 cars, RV's and trucks (5), it works better than R134a and at a lower head pressure so it gives you more MPG than R134a or R-12 and works has a lot better cooling on hot days than R134a or R-12.
I love it and a lot of owners of newer iron have converted R134a systems to Freeze 12 for better cooling and more MPG. It is also safe for the environment.
You can not beat the price either.

 

you can also try r414 (hotshot) it is a replacement for r12 and r134a

 

Here is some info I gathered Re: Freeze 12, or any of the Freon substitutes.

Most automotive A/C systems by design leak over time, and blends don't leak at the same rates. One componant always leaks out before the other, which makes topping off impossible. Each time the refrigerant gets a little low, the system has to be evacuated and recharged to keep the mix the same. That was why I had suggested the R12, it can be topped off if there is a very slow leak.

If you did go with 134a it could be topped off if some leaks out over time. Don't forget the issues with the oil, and finding a replacement condenser to handle the conversion might not be so easy.

I know its tough when you are fixing an older car, you never know when something else is going to fail. I've been down that road more times than I want to talk about.

Frank D

 

The bigger the condenser the better, double up or whatever, most are limited by space requirements. Blowing more air through it the better. The job of the condenser is to cool the hot gas refrigerant and make it condense to a liquid. The more it cools the liquid refrigerant, the lower the high side pressure will be, which will make the system cool better and your compressor to last longer. For this example, I'll use R134, since I have the Temp/Pressure chart handy. The temperature of the liquid leaving the condenser is DIRECTLY related to the high side pressure, check your R134 Temp/Pressure Chart. You can measure the temperature of the condenser discharge line with an IR Thermometer. You can see that if the pressure is 228 lbs, then the temp of the line is about 140 degrees. You can tell what the high side pressure is by measuring the temp of the condenser discharge liquid line. If you measure the condenser liquid line temperature to be 145 degrees, then consulting the chart, you see that the high side pressure is about 244 degrees. Now, if you can increase the cooling effecientcy of the condenser so that the temperature drops down to 130 degrees, the high side pressure will drop down to about 198 lbs. All it takes is to be able to transfer MORE heat OUT of the hot gas refrigerant, and you can do that basically TWO ways, either blow MORE AIR through the condenser to increase the heat transfer rate, OR use a larger condenser that has more heat transfer surface area to increase the heat transfer rate. Finding something to fit is the trick.
No matter what refrigerant you use, the basic principles remains the same.
Good Luck,
E.D.

 

Solutions

I found an issue that helped some. These model truck have a recirculation actuator mounted under the hood over the fan that re-circulates the air when on max cool. The tube is plastic and is positioned in such a way that it rubs on hoses as it comes out of the harness. For those reading this make sure the vacuum tube is not broken, it makes a big difference. 10 to 20 degrees.

A replaced fan clutch also helped some, and if the electric fan helps some at idle I may get nearly acceptable cooling.

As far as a condenser

A company here http://www.ackits.com/index.cfm?fuseaction=Parallel makes a parallel flow condenser and they have many generic sizes and kits. Please let me know if link is inappropriate. Just intended to be informative.

Been almost 20 years Thermodynamics class E.D. That gives me an idea for a spreadsheet program. Hehe.

Thanks for your input Frank and E.D. I really appreciate your knowledge and time. Subford too.

Brian