1972 Highlander -The making of a daily driver

[70monte]

I re-read your post and one thing I noticed that you did that you should never do is use a flush product in the compressor itself. It will ruin it. Also never attempt to flush any lines that has a muffler in it like the line on top of the compressor that has that can looking thing on it. To be honest, you have to be almost a 100% sure that you are getting all of the flush out of everything or you can possibly destroy things. The only thing that I will flush is hard lines with no mufflers and the evaporator. Everything else I replace.

The other important thing is to charge by weight. That is the most accurate way to get the charge right. Pressures are only a general guide and outside temps will affect what your pressures are. If you are using r134a, only charge to about 80% of the r12 amounts. I don't know on the freeze 12 stuff.

Also make sure your fan clutch is working correctly. If it is old, replace it. I usually replace them just to make sure.

Try and get some stuff called Nylog for your connections and o-rings. Great stuff and will help prevent leaks at these areas. Go to their website for place that you can get it locally.

Finally, go to www.autoacforum.com and do some reading or register and ask questions. Very imformative website on auto AC. Good luck.

Wayne

[BruthaMan]

Appreciate the advice Wayne and excellent point about flushing. I purchased two extra quarts of mineral oil to use specifically for flushing the compressor. I had read the same thing you are noting, about not flushing the compressor with a flushing agent. Instead, use the type of oil planned for the system, and flush the compressor with that.

I filled the compressor with mineral oil (r12 based) and let it sit over night. Then drained it. I then filled it, rotated clutch back/forth numerous times, twice more, and let it drain overnight.

I do believe one of the early errors I made (and was not aware of at the time), was charging the system as a liquid (can upside down). For all the time invested in studying, reviewing threads, etc, I had not seen that. Maybe one of you guys can confirm, but I've since done some reading and the charge should be with can up, as a gas, into the system. Is that correct?

I really do believe the POA valve has something nefarious going on. Everything else is pretty much new, except for the evaporator core. We've flushed it numerous times.

The low side pressure would just start to skyrocket. Even weirder, was, we would have idle between 1500 - 2000 and just get to that point where low side reading was looking good (around 29-30) and high side was always much lower than it seemed it should be (around 190 - 210) on 95-100 degree day. But when we let off idle, the low side would soar up the compressor would start trying to lock up.

[Low Elco]

I admittedly know squat about this, but it does sound hydraulicish. Like going fast is enough to keep it moving and slowing down drowns it? Hell, IDK!
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[70monte]

Charging as a gas is the safest way to charge the system and is what I would recommend.

You did right by flushing the compressor with the mineral oil. Also make sure to put the correct amount of oil in the system. I don't know what that amount is for your truck but it's probably around 8 ounces. That is what my later model chevy trucks take that are single air systems. Don't put all of the amount into the compressor. Put about 3-4 ounces in the compressor and the rest in the other AC components.

Also make sure when you are charging that you are doing so through the low side only. DO NOT have the high side open when charging.

I want to again express he importance of a fully functioning fan clutch. It is critical for proper AC function, especially at idle. Make sure the proper fan shroud is in place.

When you begin charging again, if the pressures start to go up, try misting the condensor with water and see if the pressures come down.

The POA valve could be malfunctioning. I have not really messed with one much but have read that they can be troublesome and that most aftermarket ones are not very good.

Go to that website I referenced above and do some reading. Here is a testing procedure for POA valves from that website.
http://www.autoacforum.com/messagevi...threadid=16311

Wayne

[DevilDog Aggie]

Originally Posted by 70monte

Go to that website I referenced above and do some reading. Here is a testing procedure for POA valves from that website.
http://www.autoacforum.com/messagevi...threadid=16311

Wayne

Wayne - Thanks for the website! That is next on my agenda after the power steering pump. Also thanks for all the great tips and info. Not knowing diddly squat about AC systems and to borrow part of Low's comment, if he lives 10 miles from hell, I must be about 10.5 or 11 miles! :-) 103 in DFW yesterday and same expected through Friday. But the weekend looks promising.

[Tinkermc]

I love all this free info found here on the forum I bookmark each in my favorites so I don't have to go look for the same info again.

[70monte]

Originally Posted by DevilDog Aggie

Wayne - Thanks for the website! That is next on my agenda after the power steering pump. Also thanks for all the great tips and info. Not knowing diddly squat about AC systems and to borrow part of Low's comment, if he lives 10 miles from hell, I must be about 10.5 or 11 miles! :-) 103 in DFW yesterday and same expected through Friday. But the weekend looks promising.

No problem. That website has helped me tremendously for the past six years since I did my first AC repair job. I probably have learned most of what I know about auto AC repair from that website and the people who responded to my questions. There are a lot of very knowledgable people on that website, with many of them doing auto AC repair for a living. The forum is actually hosted by the owner's of a repair shop in Arizona.

I have saved thousands of dollars over the years by being able to do these repairs myself. The initial investment of equipment cost a little bit but after that it saved a lot.

Wayne

[DevilDog Aggie]

Actually looking back through the thread, it was BruthaMan from San Angelo who is 10 miles from hell!!! No offense Low!!! Must have been after a few beers and contemplation of what's next when I posted that!!!

[Low Elco]

No worries, I think the whole state of Texas is in the next county over from hell at this point! (love the people and the place, buy dayum, y'all got heat!)

[DevilDog Aggie]

Originally Posted by Low Elco

No worries, I think the whole state of Texas is in the next county over from hell at this point! (love the people and the place, buy dayum, y'all got heat!)

LOL! Yep we do! 103 again today.

[70monte]

I'm headed to Texas on vacation starting on the 15th. I'm not looking forward to the heat as it's been hot enough here in Missouri.

Wayne

[Tinkermc]

Texas has plenty of heat to share, I lived in Greenville for awhile and it also snows once in a while.

[DevilDog Aggie]

Originally Posted by 70monte

I'm headed to Texas on vacation starting on the 15th. I'm not looking forward to the heat as it's been hot enough here in Missouri.

Wayne

105 I think is the high today in Dallas/Ft. Worth. Although there is a front coming through tonight that should drop us down to 88 or so over the weekend! :-( Not a big fan of summer's here! Give me Fall/Winter/Spring any day!!!!!

Where you headed?

[DevilDog Aggie]

Originally Posted by Tinkermc

Texas has plenty of heat to share, I lived in Greenville for awhile and it also snows once in a while.

LOL! We do get snow here, but then it is usually followed by sleet. Which is then followed by all the idiots with 4x4's getting out on the road. Of course the thing they forget is they may have 4 wheel drive, but not 4 wheel stop! LOL!

[70monte]

We are going south of San Antonio. The timeshare we own has a few places in Texas that we can go to. I'll have to ask my fiance the name of the town we are going to.

Wayne

[asmith1923]

HIJACKED

Let's get back on topic, I'm sure the weather channel has a message board ya'll can discuss the weather on.

How's it going Bruthaman? Any new AC revelations?

[BruthaMan]

Hey Guys!

Glad I'm not the only one who doesn't like the heat! I'd much rather be in Red River, NM. My wife and I used to go there all the time, just to get away and enjoy the mountains, when we lived in Amarillo. Haven't been back since we moved down here.

OK, update on the AC. I ordered some more ES-12a. I know, I know...but it's cheap as biscuits and I've blown more money on R12 that I'd ever care to admit. As well, oddly enough, through all this ordeal, I had best results with it.

Today was an unusually cool day. Went to bed at 3:30am yesterday, damn neighbors dogs woke me up about 7:30. Those miserable flea bags. Used to be real quiet here, but in the last year, apparently neighbors all around us were not content with the peace and quiet and now three houses behind us and one next to us, have dogs that yap at all hours of the day and night.

But I digress. So I got up and decided to get some donuts. Nice peaceful drive across town. Very, very cool this morning. I call it "free air conditioning!" Ran a few errands, got the oil changed in my truck, picked up a few "man supplies" and headed back to the house. Was going to do the AC work on Monday, but by noon, it was still unusually cool. 75-80 degrees. Apparently we received a cold front.

I could not resist working in such beautiful weather, so I got to work. Changed out the expansion valve, swapped out the POA valve with the new POA eliminator. Did the wiring, changed o-rings, pulled vacuum, tightened down a few connections (mild leak in one of them) and by 4pm, had everything read to charge.

One of my son's friends (he's about 23) came over to work. He comes over a few days per week to do work while he's in college. We broke out the hoses, cracked the case of ES-12a open and started the process. First can. Could feel some cooling on the POA eliminator! Second can, getting colder, but low and behold, the famous squaking roared her ugly head. Momentarily. Decided at that point, to take the truck out for a drive and see how cooling did on the road.

Went well. It did the squaking thing one time, on the way back. I quickly turned AC off. Pull back into the drive way, turn it on and it ran fine.

So at this point, we're back to the unstable low side pressure. It goes fine for a little bit, then WHAM, it jumps up about twice as high as it should be. Let it rest a bit, re-engage, and it's fine. Baffles science, right?

At this point, it was around 7pm and Jacob had to leave, so put everything back in the garage and closed shop for the day. We did get cooling though! We took off the right side of the evaporator core box and used an infrared heat gun on it. At one point, it dropped into the high 40's. Mostly averaging low 50s, so it IS cooling...but the low side pressure goes haywire intermittently.

My mind keeps running scenarios through it. What would cause an unstable low side pressure? The high side doesn't fluctuate, even when the low side goes haywire, which is even weirder.

Started running process of elimination (my mind works like that, for some reason. Good most of the time, but drives me nuts sometimes because I over-analyse everything).

Hoses/lines - New
Evaporator - Not new, but has good flow and I've checked/triple checked numerous times
POA - new
Expansion valve - Reman original. I've new ones, old ones and have tried them all. Never seems to make a difference one way or the other, so I stuck with the Remanufactured one I picked up off Ebay.
Compressor - Pro6ten - New
Drier - New
Condensor - new

This runs through my mind and I think "WTH could it be? There's only so many parts there and I am getting cooling, but the low side pressure periodically becomes unstable.

So I start doing some more research and the one thing I have not accounted for as a possiblity...too much oil in the system. Looking through some posts on autoacforum.com seem to confirm this could be the issue. I know there is ten oz of mineral oil in the system. I know this, because I used my wife's measuring cup, which has oz on it, and she was not happy I used her cooking cup to measure mineral oil. (Better to ask for forgiveness than permission!).

So the plan is, tomorrow, disassemble everything again and thoroughly flush the system and drain the compressor. ES-12a works with any type of oil, mineral, ester, pag. Napa is closed on Sundays, where I've been getting it. Not sure if O'R or Autozone keep mineral oil in stock. I have about half a quart left.

The Pro6ten compressor came with instructions and a formula to determine mineral oil ( forget off-hand ). I used the number of 3.4 lbs of freon in that calculation to determine the 10 oz of mineral oil for the system, which seems in line with some of the posts I've read here.

Recommendations? Maybe try 6 oz? ES-12a requires significantly less than normal R12 or R134a. 6 oz. of Enviro-Safe is equivalent to 18 oz. of R-12 or 16 oz. of R-134a. How would you guys factor this in determining the amount of mineral oil to add to the system?

Pardon me while I scratch out some math.

3.4 (lbs) * 16 (oz) = 54.4 oz R12 for our trucks.

ES-12a - 6oz = 18oz of R12 (meaning ES-12a requires three times less compared to R12)

54.4 / 3 = 18.1333333 oz of ES-12a is equivalent to 54.4 oz of freon (3.4 lbs)

10 oz oil for 54.4 oz of R12 = .18 oz of oil per oz of freon

18.133 oz of ES-12a x .18oz of oil = 3.26 oz of oil (that seems low...I'm seeing newer systems (which the Pro6ten is) at around 5-6 oz of oil)

This is assuming there is a correlation of the amount of freon to oil. Thoughts?

I think after flushing the system tomorrow, I'm going to switch over to Ester oil. Es-12a is compatible with Ester and Ester is compatible with residual mineral oil (even though I plan to flush thoroughly) and it's easy to come by at all the parts stores.

The idea behind this is, I can start off with a lower amount of oil and if more is needed, I can get it in a charge can (not having any luck finding mineral oil in a charge can) and add more if needed, without having to evac system.

I really am starting to think this is the problem...too much oil and it's bogging the system down. It definitely seems to be a symptom of unstable low side pressure and certainly make sense when nothing else seems to.

Let me know your thoughts guys. Appreciate everyone's advice and suggestions.

[PD1292]

Hey, fellow San Angelo 67-72 owner. I am usually on the blazer side of things, but saw your name and location on the for sale/ buy side the other day. Truck looks great, good luck with the A/C.. Barry

[BruthaMan]

Hey Barry, thanks! Oddly enough, I was perusing your profile the other day. Was surprised to find a fellow enthusiast from San Angelo. Spent some time looking through your build thread. You've done an amazing job!

This Saturday (Jan 26), we're going to roll "the beast" out of the garage and see if we can get her fired up. It's been almost a year now since it last ran. It's an amazing truck. Would love to have you stop by if you have some free time. We live in the College Hills area. I can send you a PM with address if you are interested.

Wade

[Low Elco]

Well, butter my butt and call me a biscuit, you are still alive! And gonna make the black one live again? This just made my whole day! Glad to see ya, Wade!

[BruthaMan]

Hey, Low Elco! Good to see you as well!

Still kicking. I had to step back and refocus on my web businesses after the googe update in April. Really took a toll. I haven't done much of anything, but work since then.

Tomorrow will be the first day I've taken off since I can remember. Fortunately all that hard work is starting to pay off and there is light at the end of the tunnel.

My web businesses were on auto-pilot for about five years. Rarely had to do any work on them. Then that update hit in April and was a rude wake up call. Hopefully will get back to that same level by summer time, so I can start enjoying life again!

[Low Elco]

Good to hear, hope its on an even keel soon!
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[Low Elco]

Wade, did you ever get this one to act right?

[BruthaMan]

Referring to the AC system?

If so, yes...and no. The problem was a kinked line at the condenser, where the line comes out, makes a 90* bend and up a few inches to the connector. It was causing a blockage in the system, so readings were never right, pressure was too high.

However, the system is not hooked up right now. Wish it were. Driving about 400 miles round trip each weak to work. Love driving the truck, been very dependable over the past six months of these weekly trips.

It did die on me about two weeks ago on the way home. Ignition coil blew and the truck lost all power. A small backfire in the carb (at the same time) blew out the rear manifold seal, turning a 15 minute fix (including time to go to auto store to pick up new coil) into a several day project.

[Low Elco]

Dadgumint! It's always something. Glad it's been good to you overall.