Hey guys,

I bought my '99 Ranger 3.0 V6 in November, knowing its air conditioner didn't work. With being as hot as it's been, I decided to see if it actually will work after some TLC. I knowingly did it the lazy way and added a factory charge with straight R-134a from Walmart, without vacuuming out the system, just to see if it worked at all. It turned out the air conditioner works surprisingly well for a truck with 256k on the odometer. It held the charge for about 2-3 weeks. I added leak dye with some more refrigerant to see if I could find the leak. It took a while, but I found dye collecting, and moisture condensing on the bottom of my condenser, nowhere else.

Here's my little series of questions. The Chilton manual says the condenser can be removed by simply dis-mounting the radiator from its retainer bolts and angling it back to get at the condenser. Has anybody tried this on the 3.0, and how much of a pain was it? Since I will be completely opening up the system, I am planning on on replacing the accumulator/dryer, orifice tube and all O-rings. I didn't see anything in the manual on replacing these things. How is the accumulator removed? Also, with the accumulator and condenser being new, I expect to need to replace some oil in the system. How much oil would you put in the system? Any tips on hose quick disconnect sizes, etc. Would be helpful. Once everything is back together, I will recharge the system the proper way, pulling vacuum, etc so my repair will last.

This will be my first time actually messing with a real air conditioning system, and not doing thermodynamics problems for a theoretical one, haha. I've also watched a few of Scotty Kilmer's videos on DIY A/C repair and being pretty mechanically inclined, I figure I'll give it a try myself.

Thanks for any pointers!

 

I havent pulled any of the parts on a car AC before but I do residential work. Once you get things up and running if you wanna post your pressures and temperatures I can analyze and tell you if you're good to go or not. We shouldn't need to because if it holds a vacuum all you have to do is add the factory charge listed under the hood and it should be spot on but if you still want confirmation send me the high and low side pressures at operating condition after 5 minutes of running, the outdoor temperature, and the temperature of the air coming out the vents. Use a meat thermometer or a digital probe thermometer and stick it into the vent.

 

Thanks for the offer! I'll definitely let you know! I don't have a scale to do the refill from a canister, so I will need to find another 18 oz can and 12 oz can of refrigerant to get the factory 30 oz load. Walmart was sold out the last time I went in, lol. I assume using those cans will be close enough, there will he some residual R-134a in them, but it shouldn't be too bad.

 

I got the condenser in today, it was a piece of cake to get out of the truck, you only need to take out 8 bolts to get it out! My pressures were 45 PSI on the low side, and roughly 220 PSI on the high side, it was around 90 degrees outside, if you'd like to check your charts. It's probably low. They don't seem out of wack, like there's a clog, etc.

I had a few technical difficulties. I couldn't figure out why the vacuum wouldn't hold after pulling one. I put more dye in and started adding refrigerant, expecting to have to hunt for a hidden leak, again. About halfway through the 18 oz can, I noticed dye splattering around the the high side valve. It turned out the valve on the high pressure guage was opened too far the whole time it was hooked up, and not letting it seal with the cap. I assume that's what was breaking my vacuum. It probably helped get the air back out, since the system was running.

I took the guage and pump back, added some more R-134a and brought the low side pressure to 50 PSI, with the outside air at 86 F. Does this sound good?

 

So your system has air in it. Those pressures are too HIGH. Thats gonna put prenature wear on your compressor. You need to pull the refrigerant out and pull a vacuum on it again. Then refill to the exact ounces listed under the hood of r134a. Use a scale.

 

So i wanna see 35 low, 145 high, or somewhere close on an 80 degree day.

 

I'll look for a scale. When I started filling, I had 18 oz and 12 oz of refrigerant, to meet the factory 30 oz load. The valve being open is what really threw the numbers off. I'm planning on buying a myself
a set of guages tomorrow, and possibly a vacuum pump, so I'll be able to do it again with my own tools. I'll verify the pressure readings and will post them.

 

So I got the refrigerant reclaimed, and put my new accumulator in today. I bought my own pump and gauges, ran the vacuum pump for 45 minutes, let it sit for 20 minutes and had no loss of vacuum. I charged the system to factory spec with a scale. It was between 85 and 90 degrees outside, the pressures came to 40 psi low, and 220 high. Are these still too high? There is definitely a difference in how the system's operating. When the air was in the system, the compressor would kick off and on for the first minute or so of operation, then run continuously. It no longer kicks off and on, on start-up.

 

How long had the truck been sitting and idling when you recorded those pressures? I need you to take these pressures within just a minute or two of kicking on the AC.

If you have to do it again, remember to provide a high and low pressure and an outdoor temp.

What it reads to me is you overcharged it a bit, the pressures are higher than i would like. However, if it was idling along for a bit that can explain it because you arent moving enough air through the condenser (by driving) to cool it efficiently. I want on a "cold start" of your AC system between 30 and 35 psi on the low side. Your high side is something i am less concerned with but try to target between 160 and 190 psi at 85-90 outdoor temp.

 

Those pressures were after it had been sitting and idling long enough to fill the system, so probably 20 minutes or so. I did notice when the truck is moving, the air's a bit cooler. Does that help?

 

This has less to do with it moving than it does your engine turning more rpms and the compressor spinning up. Idle for a bit inside the cab. Now rev the engine up to 2k revs, and notice the temp change in the vents. Even modern cars do this.

You need to rerun the test, now that the system is charged. Go set to max ac, let the truck idle for 2 minutes. And then record your pressures. Record outdoor temp next to the truck (not your phone app. If you dont have a thermometer just use your phone app). I wanna see what your pressures are. Again, lets shoot for 35/175 on a 85 degree outdoor temp

 

So what's the news, chief?

 

I ran the AC for 2 minutes this morning, it was 80 degrees, per the weather station on my garage. The low pressure side was 30 to 31 PSI, the high side hung around 175 PSI.

 

thats about perfect buddy. Does the vent feel cold?

 

yeah it's cold, when I emptied the accumulator, just dye from the leak locator came out. It needs 9 oz, I filled up the new one with PAG40 oil, roughly 6 oz. I put 3 oz in on the last charge, so should be OK. The compressor used to clunk when it first came on, sometimes. That hasn't happened. I did notice the high side gauge fluttered for probably 4-5 seconds before settling and rising to the 175. Might be the compressor wearing? I had no idea the oil was that empty.

 

As long as you have the proper oil amount according to the OEM, and the proper charge in the system according to the OEM (and based off of pressures in this case, like we do in the field), then your system should be fine. Just make sure your radiator fan is clean and unobstructed, make sure your fan in the cab is blowing strong airflow out the vents, and also make sure your condenser is clean. You can use a garden hose with the high pressure nozzle and blow the dirt out of it. They also sell coil cleaner and you can rinse it off with a hose. Thats about all you can do at this point.

 

Can we get an update OP?

 

It's still blowing cold, even in this heat! When it had air in the system, it didn't cool as well as now. I work at a plating company that's hot this time of year, and drove home with the air on full blast last night. It cooled the interior so much that humidity outside was condensing on the windshield, lol. I'd call it a successful repair!

 

Great work. Glad I could put my HVAC degree to good use to help someone out. I got a paypal account if you wanna send me a service fee lol
Just kidding, enjoy the comfort.

 

Thanks for the help! I learned a lot from messing with this, I thought about making use of the vacuum pump and R134a gauges I bought and fixing friends' cars' ACs for cheaper than shops charge. Get good enough at it, might be able to start a business just doing HVAC repair on cars, lol. My brother's Silverado hasn't blown cold AC in years, might offer to help check it out this weekend.

 

Yes but you have to have an understanding of the refrigeration cycle. Technically you are also supposed to have an EPA 608 or EPA 609 certification to handle refrigerants. So have fun with it but take time to educate yourself on whats going on with those pressures. I was seeing a whole picture from my house states away from you, just based on the pressures and temperatures you sent me, but you were just following my instructions.

Take time to learn the refrigeration cycle and understand what those pressures are telling you.

 

That's true. There are things like whether a vehicle has an accumulator/drier, or receiver/drier, where they are, etc. I studied thermodynamics in college, and understand the basics to how they work. The refrigerant gets compressed by the compressor and becomes a hot, high pressure liquid that flows into the condenser, it cools in the coils, stays liquid, and makes its way to the evaporator through an expansion valve, orifice tube, etc, and expands inside the evaporator. The refrigerant absorbs heat as it evaporates into gas, chilling the air in the conditioned space. From there, the warmed gas goes back to the compressor and the cycle repeats.

Excessively high or low pressures can mean blockages, etc. that kind of thing is probably more difficult to diagnose and comes through experience, and or learning in classes beyond the physics part that I took. Refrigerants are also greenhouse gases, so they're illegal to release, etc. That's probably why you need EPA certifications. It might be worth checking out at some point.

 

yes i am quite sure you are smart enough, in the sense that you have a grasp on how these things work, and youre not just joe homeowner. However, play it cautious because theres a lot at play and its easy to get tripped up and mess up a diagnosis. When youve done it 100s of times like myself it becomes second nature, you can see a set of conditions and usuly pinpoint the problem without breaking out your tools yet. A young buck like you needs to play it smart and just pay attention to what the gauges are telling you, and think it through carefully to conclusion. Youll figure it out for sure.

The one thing that grinds my gears is the stigma against tradesman. Yes we are dirty and smelly. I sweat all day in the sun and i lay in dirt, ****, concrete, rocks, hair, crud, you name it. But what we do is an art, and a science. Its called a SKILLED trade for a reason. Your plumber is probably making almost as much as some guys with graduate degrees. Tradesmen are very smart, when you watch one work with tools its almost a magical experience. Everything just seems to fall into place perfectly. And that goes for auto mechanics, electricians, hvac techs, carpenters, sheet metal workers, on and on. Being an expert in your field is a very rewarding experience. I'll lay in **** and **** all day to keep doing what i do. The desk life or office drone life isnt the life for me. I'm far from an expert, dont get me wrong. I have a degree, a number of field certifications, and closing in on a year of field experience. Far, far away from an expert. But I will be soon, and this education pays for itself.

Today I replaced a condenser fan motor for a guy, he was so happy. The bill was over 500 dollars. Motors arent cheap, believe me. But knowing that I myself am insulated from this type of cost on my own home is very comforting. I can hit up the supply house and pay 145 bucks for it and swap it in myself in 30 minutes. Over a lifetime these sorts of savings practically pay off the degree. Now imagine how much i can save when i do a full system install!! Thousands!

PM me if you ever need any help with the refrigeration stuff buddy.