relocating AC dryer with factory stuff .... Eddited content and instructions (1 Viewer)

[flintknapper]

I've sourced some R12 so that’s not an issue. But when retrofitting a system to r134a it’s supposed to use 90% less than the r12 you took out (if you didn’t have a leak and your system is full). Also an r134 system uses a much larger condenser, if you can run r12 thru the same system it will be much colder, and to be honest in this Alabama heat it would be well worth it if my A/C was 5 degrees colder.

^^^^^^

When switching to R12......you'll need 10-20% more (by weight) refrigerant than R134a. Not a big deal...but you will need to 'creep up' on the ideal amount (add slowly, watch high and low pressure and monitor vent temps until you see no more gains).

R12 will not be "much" colder. IMO...it isn't going to be worth your effort, but far be it from me to try and talk you out of it.

R12 will 'recover' faster (from heat soak) but the gains in vent temps (lower) will be minimal.

It doesn't get any hotter/humid in Alabama than Deep East Texas and my R134a system does a good job of cooling. FWIW....I would spend my time, effort and money making sure your system is properly working and stay with 134a. But that's just my .02

 

[-Spike-]

From what I've heard, PAG and mineral oil don't get along at all. Getting all the PAG out of the system would be extremely difficult. The evaporator and condenser have parallel tubes, so you can't be sure you're getting everything out- air or solvent will follow the path of least resistance and may leave some oil behind. If it turns to goo, you'll be replacing the entire system. I don't know if there are alternative oils that play well with PAG and R12, but that might be the trick there.

For the record I'm with flintknapper, converting to R12 seems like a step backward. Maybe do a search for Envirosafe.

 

[-Spike-]

"Mineral oil was the de facto A/C compressor oil used up until the early 1990s thanks to its ability to mix with the R-12 refrigerant, but when R-12 was shelved due to its ozone-depleting properties, mineral oil had to be scrapped as well because of its inability to mix with the more environmentally sound R-134a.

R-134a became the refrigerant of choice in U.S. mobile air conditioning systems in 1994. Its popularity coincided with the emergence of polyalkylene glycol (PAG) oil, which mixed well with the new refrigerant.

However, because mineral oil and PAG oil are not to be mixed, another A/C compressor oil was needed to bridge the gap. The solution was ester oil." - Article- 'A/C Compressor Oils: Types, Uses And Differences'

 

[flintknapper]

From what I've heard, PAG and mineral oil don't get along at all. Getting all the PAG out of the system would be extremely difficult. The evaporator and condenser have parallel tubes, so you can't be sure you're getting everything out- air or solvent will follow the path of least resistance and may leave some oil behind. If it turns to goo, you'll be replacing the entire system. I don't know if there are alternative oils that play well with PAG and R12, but that might be the trick there.

For the record I'm with flintknapper, converting to R12 seems like a step backward. Maybe do a search for Envirosafe.

SMALL amounts of PAG (which is a fully synthetic oil) in the system would not necessarily pose a big problem.

The two oils are not harmful to one another and one does not alter or degrade the other. They just don't 'Mix' well (Oil Miscibility). So one of them (in this case the PAG) will not circulate homogeneously through the system.

Going to Mineral oil with R12 (and a small amount of PAG) is less a problem than if he were going the other way around. Mineral oil in R134a and PAG....will just find a low spot and pretty much sit there.

Bottom line...it is best to get as much of the PAG out as is possible. The OP will also be 'guessing' at the amount of Mineral oil to use with his old compressor. Too much and cooling will suffer. Too little and premature compressor failure is the result.

A properly working R134a system with an Aux fan hooked up to the Trinary switch should give him all the cooling he would need (short of a desert environment). So much easier to do.

 

[flintknapper]

"Mineral oil was the de facto A/C compressor oil used up until the early 1990s thanks to its ability to mix with the R-12 refrigerant, but when R-12 was shelved due to its ozone-depleting properties, mineral oil had to be scrapped as well because of its inability to mix with the more environmentally sound R-134a.

R-134a became the refrigerant of choice in U.S. mobile air conditioning systems in 1994. Its popularity coincided with the emergence of polyalkylene glycol (PAG) oil, which mixed well with the new refrigerant.

However, because mineral oil and PAG oil are not to be mixed, another A/C compressor oil was needed to bridge the gap. The solution was ester oil." - Article- 'A/C Compressor Oils: Types, Uses And Differences'

The best application for Ester is when you convert from R12 to R134a...because it DOES mix well with Mineral Oil.

So...IF some amount of Mineral Oil were still in the system, no big deal. Its just that Ester is not as good a lubricant as PAG...but better than Mineral (for 134a).

Additionally, PAG and Esters are much more Hygroscopic than Mineral.

 

[KrOswalt]

The R12 condensor for a 93 80 series is exactly the same dimensions as a 134a condenser for a 97 80 series.

Well between that and not being able to get the oils completely flushed I suppose there’s no reason in even trying to back track to r-12. I was under the impression the older condensers were smaller. But, all of this info is much appreciated

 

[KrOswalt]

With all that being said, my system works just fine, obviously it doesn’t work as good at idle when it’s hot out, but after driving at highway speeds it’s very cold, I just haven’t measured the vent temps with a thermometer. I was just under the impression that my condenser on an r134 system was larger, therefore going to r12 would be a plus, but this is not the case so i don’t see where r12 would be a big positive, as most have mentioned.

But, when I relocate the dryer and get it off the bumper, I was told a new dryer would help, is this also true? Also, with all this debacle going on I’m assuming since you can retrofit most (if not all) r12 systems to r134 all the parts I have coming will work just fine? Simply vacuum the system, relocate correctly as OP has done, and refill?

 

[landtank]

Poor AC performance at idle is commonly a fan clutch issue.

 

[flintknapper]

But, when I relocate the dryer and get it off the bumper, I was told a new dryer would help, is this also true?

A 'new' dryer will work better than an old (saturated) one only by virtue of the unsaturated/uncontaminated desiccant it holds. The purpose of the dryer is twofold (desiccant absorbs and holds moisture that might be in the system but the dryer also stores oil and liquid refrigerant when not needed). It is this second function that folks don't understand when they tweak the lines and turn it horizontally.

Also, the dryer (sometimes called an receiver) will work best the farther away from a heat source as practical. Too much heat will cause the liquid refrigerant to boil into vapor. The refrigerant needs to be in liquid state as it goes through your TXV and into your evaporator in order to do any cooling.

So...the dryer located low behind the bumper is a better spot (functionally speaking) than in front of your battery, BUT moving it is a better choice for those who off-road where the possibility of smashing the dryer exists.

 

[KrOswalt]

A 'new' dryer will work better than an old (saturated) one only by virtue of the unsaturated/uncontaminated desiccant it holds. The purpose of the dryer is twofold (desiccant absorbs and holds moisture that might be in the system but the dryer also stores oil and liquid refrigerant when not needed). It is this second function that folks don't understand when they tweak the lines and turn it horizontally.

Also, the dryer (sometimes called an receiver) will work best the farther away from a heat source as practical. Too much heat will cause the liquid refrigerant to boil into vapor. The refrigerant needs to be in liquid state as it goes through your TXV and into your evaporator in order to do any cooling.

So...the dryer located low behind the bumper is a better spot (functionally speaking) than in front of your battery, BUT moving it is a better choice for those who off-road where the possibility of smashing the dryer exists.

My main reason for moving is for off-roading purposes, or else I’d move it up in the bracket like some people do.

 

[KrOswalt]

Poor AC performance at idle is commonly a fan clutch issue.

If I’m sitting in my carport/in the shade it performs perfectly, and is borderline freezing. But when it’s 95+ outside and the “real feel” is 105 with 90% humidity you can tell it struggles at idle or in slow traffic. I guess I could hook some gauges up and check my high and low side pressures but from what I’ve read this is a common issue

 

[flintknapper]

If I’m sitting in my carport/in the shade it performs perfectly, and is borderline freezing. But when it’s 95+ outside and the “real feel” is 105 with 90% humidity you can tell it struggles at idle or in slow traffic. I guess I could hook some gauges up and check my high and low side pressures but from what I’ve read this is a common issue

Yes, you have the same ambient conditions we have here (Deep East Texas). Most days in the summer (July-Sept) will be 95-98° F. with some days 100-105° F and stifling humidity.

The decrease of low speed performance is typical for the system in a stock Land Cruiser. Virtually ALL A/C systems work better with air flow (vehicle speed) and engine rpm increase. So...what can we do to 'improve' the low speed performance. Three things.

1. Check to see that all system components are in good condition and that the system is properly charged. (I.E. your condenser and especially your evaporator must be clean). If you've never pulled your evaporator I can assure you it is filthy. Don't overlook your radiator either....air flow first goes through the A/C condenser then your radiator, BOTH need to be clean and any bent over fins straightened up.

2. If your fan clutch is old...check it. I highly recommend doing the 'fan clutch mod' (replacing the silicone fluid with about 48-50 ml. of 20K cst.)

3. Add an Aux fan. Wire it as you wish (to come on automatically or manually).

These things will insure your A/C system will keep you comfortable. IMO it is a much better solution than trying to retrofit to R12 in hopes of gaining increased cooling.

I understand your goal...I really do. I'm sure if you could get a 10° F. drop in vent temps (or a little more) you would be satisfied. The difference in 60° vent temps (hot day, full sun, stuck in traffic) and 45-50° vent temps is stark! But it will only be had by making sure your system is in tip-top shape and by improving air flow.

There is NO such thing as a product that will let you just 'pour in the cool'. It's all about the 'system' my friend.

 

[landtank]

If I’m sitting in my carport/in the shade it performs perfectly, and is borderline freezing. But when it’s 95+ outside and the “real feel” is 105 with 90% humidity you can tell it struggles at idle or in slow traffic. I guess I could hook some gauges up and check my high and low side pressures but from what I’ve read this is a common issue

Its about the clutch timing that is your problem. Your clutch is late to the party. I went through this last year on hete with a huy and once he got the clutch to come in on time the idle AC performance improved greatly. He had all the data in that thread. I'll try and find it.

 

[landtank]

Here is the thread.

Micro-Tube Parallel Flow Condenser

I jumped in to point out the clutch was a problem about half way through.

 

[GLTHFJ60]

Necro bump to thank @landtank for the easy tutorial.

I put my splices in slightly different places. Swap couldn't be easier! These lines came out of a 91-92, which apparently means you don't need to cut the hole in the core support. I enlarged the notch in the battery tray for the OEM AC line and it fit through the OEM AC line hole in the core support perfectly.

Thanks again Rick!!

 

[landtank]

thanks for the post. I bought new lines and quite possibly could have routed it that way.

 

[landtank]

Eddited instructions and parts used. System had low charge after 1 year. Switched to swagelock unions and things have been better.

 

[GLTHFJ60]

Where'd you get them?

 

[landtank]

company called Titan. Found them by googling swagelock U5

 

[RedFiveAZ]

Any chance for a part number for the swagelock?