Fixed AC
Fixed AC
Howdy R-F,
For many years (30+) I've always wanted to do my own automotive AC repairs. To many times I've had to take cars to a shop and pay someone else to fix AC for me. Well I finally dove in and researched how to do it myself. I often help others with car repairs so I decided to get some mid grade AC tools and teach myself a new skill. (I did A LOT of reading and YT video watching)
I had 2 problems with my (new to me) 98 ranger.
1. The AC didn't blow cold and the compressor would only kick in/out.
2. The air would blow only though the defrost duct at moderate throttle and steady 55+ speeds. (worked ok at light throttle where vacuum is high)
The vents not working was due to the vacuum hose running to the heater hose valve in the engine room. This was a bit tricky to find because where it was leaking was not visible and the lines seemed ok when pulling on them. Pipe degradation and chafing occurred between the AC accumulator and the air box. (it fully broke in half only after I pulled hard on it) Apparently this is a typical place for it to leak due to excessive heat.
I took some close up pics of this line and the area too. Seems that the hose deteriorates and gets crumbly. In the attached pic you can see how scraping with your fingernail makes it crumble. Outlined in yellow is how I re-routed the new part of the pipe to help keep it away from heat & from touching hard parts that it originally scraped against.
The AC wasn't working because it was leaking out of the (original) rusted accumulator. It was wet and it would loose about 1psi a minute when pulled down under vacuum.
Since I had the tools I decided to do an experiment. I wanted to see what would happen by using the redneck method of just adding two 12oz cans using the cheap fill w/gauge tool that you can get anywhere. (I had an old one laying around from the multiple times I've tried to add some). I added two cans and the AC did work. But the air would only get down to 65F in normal mode and 58-ish in MAX AC. I later hooked up the new gauges and the low side showed 25psi (cheap fill guage showed 45) and the high side was only 50psi.
So then onto a proper fix...
I bought a 2 stage 5CFM Robinair vacuum pump & R134a gauges and a hand vacuum pump from a local store. Air tools came from Amazon, Parts came from my favorite local parts store, and R134a came from WM ($4.88 at WM vs $12 at parts store). Yes this pump is overkill for a car but I was wanting something that had 2 stages (35micron rating) and that has some level of quality. Also its big enough to do a home AC system if needed.
Using my 98 Ranger as my learning tool / guinea pig.. I replaced the accumulator and put it under a vacuum for 10 minutes to test for leaks. It held for 30 minutes so I let it draw down for another 40 minutes. I made sure to purge the air out of the fill line each time a new can was used and 30oz later my AC is blowing 39F on a 96F day! I've really gotten a sense of accomplishment out of this. I really.. REALLY wish I had done this yrs ago. I'd have easily payed for these long before now.
Here are some amazon links for the pump & gauges. And some YT vids. And some pics that you might find helpful.
Regards, Rich
For many years (30+) I've always wanted to do my own automotive AC repairs. To many times I've had to take cars to a shop and pay someone else to fix AC for me. Well I finally dove in and researched how to do it myself. I often help others with car repairs so I decided to get some mid grade AC tools and teach myself a new skill. (I did A LOT of reading and YT video watching)
I had 2 problems with my (new to me) 98 ranger.
1. The AC didn't blow cold and the compressor would only kick in/out.
2. The air would blow only though the defrost duct at moderate throttle and steady 55+ speeds. (worked ok at light throttle where vacuum is high)
The vents not working was due to the vacuum hose running to the heater hose valve in the engine room. This was a bit tricky to find because where it was leaking was not visible and the lines seemed ok when pulling on them. Pipe degradation and chafing occurred between the AC accumulator and the air box. (it fully broke in half only after I pulled hard on it) Apparently this is a typical place for it to leak due to excessive heat.
I took some close up pics of this line and the area too. Seems that the hose deteriorates and gets crumbly. In the attached pic you can see how scraping with your fingernail makes it crumble. Outlined in yellow is how I re-routed the new part of the pipe to help keep it away from heat & from touching hard parts that it originally scraped against.
The AC wasn't working because it was leaking out of the (original) rusted accumulator. It was wet and it would loose about 1psi a minute when pulled down under vacuum.
Since I had the tools I decided to do an experiment. I wanted to see what would happen by using the redneck method of just adding two 12oz cans using the cheap fill w/gauge tool that you can get anywhere. (I had an old one laying around from the multiple times I've tried to add some). I added two cans and the AC did work. But the air would only get down to 65F in normal mode and 58-ish in MAX AC. I later hooked up the new gauges and the low side showed 25psi (cheap fill guage showed 45) and the high side was only 50psi.
So then onto a proper fix...
I bought a 2 stage 5CFM Robinair vacuum pump & R134a gauges and a hand vacuum pump from a local store. Air tools came from Amazon, Parts came from my favorite local parts store, and R134a came from WM ($4.88 at WM vs $12 at parts store). Yes this pump is overkill for a car but I was wanting something that had 2 stages (35micron rating) and that has some level of quality. Also its big enough to do a home AC system if needed.
Using my 98 Ranger as my learning tool / guinea pig.. I replaced the accumulator and put it under a vacuum for 10 minutes to test for leaks. It held for 30 minutes so I let it draw down for another 40 minutes. I made sure to purge the air out of the fill line each time a new can was used and 30oz later my AC is blowing 39F on a 96F day! I've really gotten a sense of accomplishment out of this. I really.. REALLY wish I had done this yrs ago. I'd have easily payed for these long before now.
Here are some amazon links for the pump & gauges. And some YT vids. And some pics that you might find helpful.
Regards, Rich
Last edited by wydopnthrtl; Jul 6, 2018 at 05:16 PM.
Dngr Rngr, a coworker went the cheapest possible route and he had success. He bought a pump and gauge set for about $135. With the low CFM single stage pump a guy would want to let it draw vacuum for about 1hr and then make 100% sure the fill line is purged of air. It should work well and I'd think for no more than $150 (+ replacement parts) the compressor, gauges, and R134a could be made to work properly.
IMO for only slightly more than a shop would charge a guy/gal can do this by themselves.
btw, your "supposed to replace the accumulator/dryer" when you have a completely emptied system. In my case it was rusted and leaking so it had to be done anyway. Rock auto has them cheap ($15+shipping+tax) but I didn't want to wait for delivery. So I went to my local Adv auto and got one for $36 out the door.
In total I spent $360-ish on tools and $51 on parts/refrigerant. Next weekend I'm doing my mother in law's and my daughters car. In those cases it should be $10-$15 per car because all they need is a recharge. (15+ yr old cars)
Regards, Rich
IMO for only slightly more than a shop would charge a guy/gal can do this by themselves.
btw, your "supposed to replace the accumulator/dryer" when you have a completely emptied system. In my case it was rusted and leaking so it had to be done anyway. Rock auto has them cheap ($15+shipping+tax) but I didn't want to wait for delivery. So I went to my local Adv auto and got one for $36 out the door.
In total I spent $360-ish on tools and $51 on parts/refrigerant. Next weekend I'm doing my mother in law's and my daughters car. In those cases it should be $10-$15 per car because all they need is a recharge. (15+ yr old cars)
Regards, Rich
Last edited by wydopnthrtl; Jul 7, 2018 at 05:42 AM.
5 month update.
Been driving the Ranger daily and took it on one road trip. Everything is working perfectly and the new vacuum hose routing shows no sign of heat degradation or chafing.
Its getting cold here in Ohio and I'm not sure what temp the AC compressor stops working? But even down in the low 40s the AC compressor seems to be working and pulling moisture out of the cab's air.
Been driving the Ranger daily and took it on one road trip. Everything is working perfectly and the new vacuum hose routing shows no sign of heat degradation or chafing.
Its getting cold here in Ohio and I'm not sure what temp the AC compressor stops working? But even down in the low 40s the AC compressor seems to be working and pulling moisture out of the cab's air.
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