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R134 to R12 (re)conversion? Pages: 12

m32825 on Sun May 18, 2008 10:29 PM User is offline

Year: 1987
Make: Toyota
Model: Camry
Engine Size: 2L
Refrigerant Type: R134a

I've got my old Camry converted to R134 and everything seems to be in good order, but I'm not impressed with the cooling. I'm in Central Florida, where temperatures and humidity are both high, so I want good cooling. The system has PAG oil in it, what would I need to do to convert it back to R12?

bohica2xo on Mon May 19, 2008 2:59 AM User is offline

It depends on when your "1987" was made. In 10/1987 toyo switched to a 22mm thick serpentine condensor, that works very well. If you have the older condensor, that may be the issue.

Now that you have converted, you would need to flush all of that PAG oil out. Back to bare metal. It can be done, but it is not simple.

I would look at the condensor, both for type, and to see that it is clear of debris & that the fan is working properly. Small bugs can clog the fins on a condensor deep into the unit where you can't see. Have a good look at the air path.

I can't recall if the improved condensor was backwards compatible. Your other choice would be a parallel flow condensor, but that will require some work to install.

All of the above presumes that a proper conversion was done. If a death kit was used, there is probably way too much oil in your system, causing poor performance...

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

m32825 on Mon May 19, 2008 8:44 AM User is offline

>All of the above presumes that a proper conversion was done. If a death kit was used, there is probably way too much oil in your system, causing poor performance...

Thanks for the response. The reason I converted was because the old system died a black death. Everything but the refrigerant lines is new, but those were pulled and flushed, the condenser is a parallel flow type. From your comments it seems that what I've got should be capable of better performance than I'm seeing. Now that I'm thinking back, I cannot recall if I dumped the factory oil out of the compressor or not (it was a late night), so that might be it. Assuming I have too much oil, what's the best way to fix it? Do I have to take everything apart and flush it?

-- Carl

mthomas58 on Mon May 19, 2008 9:12 AM User is offline

Quote
Originally posted by: bohica2xo
It depends on when your "1987" was made. In 10/1987 toyo switched to a 22mm thick serpentine condensor, that works very well. If you have the older condensor, that may be the issue.



Now that you have converted, you would need to flush all of that PAG oil out. Back to bare metal. It can be done, but it is not simple.



I would look at the condensor, both for type, and to see that it is clear of debris & that the fan is working properly. Small bugs can clog the fins on a condensor deep into the unit where you can't see. Have a good look at the air path.



I can't recall if the improved condensor was backwards compatible. Your other choice would be a parallel flow condensor, but that will require some work to install.



All of the above presumes that a proper conversion was done. If a death kit was used, there is probably way too much oil in your system, causing poor performance...



B.

What's a "death kit"?

m32825 on Mon May 19, 2008 10:05 AM User is offline

>What's a "death kit"?


I think he's referring to the conversion kits available in auto parts places (i.e. not a proper conversion).

bohica2xo on Mon May 19, 2008 11:27 AM User is offline

Death Kit
Pronunciation \'dog crap\
Def.
A small kit of low quality items sold together and represented as a proper conversion from R12 to 134a. Usually contains some oil, 134a and a hose assembly to add this to a system. Included is an instruction sheet that omits important steps like flushing, dryer replacement and evacuation. Adding such a kit to an R12 system usually results in a slow (sometimes immediate) death of the system. Some personal hazard exists as well because none of these kits include a high side gauge, and catastrophic failures may result.

-----

Carl:

Sounds like you need to do some fine tuning on your system. Adding a PF condensor was more work that many are willing to do - good for you.
It may be too much oil, or an airflow issue. I can't recall if that car had the electric fan with the air doors on the shroud, or the mechanical fan with the viscous clutch?

Get some pressure readings for us. High & low side, both at idle and 1500 to 2000 engine rpm. Doors open, cabin fan on highest speed. Vent temps & ambient temp too.

If it is too much oil, you will have to get some out... and that means flushing. That system only needs 2.0 to 3.4 ounces of oil & 21 to 27 ounces of refrigerant. Let's see if it is something that can be fixed without opening the system first.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Edited: Mon May 19, 2008 at 11:28 AM by bohica2xo

m32825 on Mon May 19, 2008 12:01 PM User is offline

>Adding a PF condensor was more work that many are willing to do - good for you.

Driving a car with no air conditioning in Florida is a powerful and persistent motivator...

>It may be too much oil, or an airflow issue. I can't recall if that car had the electric fan
>with the air doors on the shroud, or the mechanical fan with the viscous clutch?

It has two electric fans on the engine side of the radiator. Both have been working properly since Tim helped me ferret out a bad radiator fan relay (probably contributed to poor cooling and death of the previous system).

>Get some pressure readings for us. High & low side, both at idle and 1500 to 2000 engine rpm.
>Doors open, cabin fan on highest speed. Vent temps & ambient temp too.

Might take until the weekend, but I'll do my homework and get back to you.

>If it is too much oil, you will have to get some out... and that means flushing. That system only
>needs 2.0 to 3.4 ounces of oil & 21 to 27 ounces of refrigerant.

I replaced or flushed everything. I have the Toyota shop manual for the car, but couldn't find a total oil figure anywhere. It has this listed for replacement of individual components:

2.7 oz compressor
1.5 oz condenser
1.5 oz evaporator
0.7 oz receiver

So I put in a little over 6 oz (plus what might have been in the new compressor already).

Last night I tried adding more refrigerant to see if I could make the foam in the sight glass go away. I chickened out around 275 psi with plenty of foaming. The only way I could make it go away was to spray the heck out of the condenser with a hose-end sprayer. Too much oil makes sense, because it would reduce the condenser's ability to dump heat and convert the high pressure gas back to a liquid, right?

-- Carl

m32825 on Mon May 19, 2008 8:26 PM User is offline

>Get some pressure readings for us. High & low side, both at idle and 1500 to 2000 engine
>rpm. Doors open, cabin fan on highest speed. Vent temps & ambient temp too.

At 1000 rpm:

low: 33 - 43 psi
high: 230 - 250 psi
vent: 66F

At 2000 rpm:

low: 25 - 35 psi
high: 250 - 275 psi
vent: 64F

Ambient temperature 83F, relative humidity 60%.

One more data point, this afternoon driving it home at a steady 2000 rpm pressures were 15 - 25 and 190 - 215, I have to guess that vent temps were in the low 60s with recirculation.

What's it all mean?

-- Carl

bohica2xo on Tue May 20, 2008 11:20 AM User is offline

Good data, thanks for taking the time to drive the car with the gauges on it.

Looks like you have a few problems stacking up there.

Your high pressures are a bit high, but not high enough to be the whole problem. The big drop in pressures on the road suggests that you may have some air bypassing your condensor on the way to the fans. Make sure that the condensor is well coupled to the radiator, so that the fans draw air through it. A bit of foam rubber can really help this.

Your bigger problem appears to be re-heating. With a low side of 15 to 25 psi, something is getting very cold. If the evaporator is flowing normally, then the air is picking up heat from the heater core. I would shut off the heater core completely & see what the temps look like. Your car has a heater control valve operated with a cable. The valve could be mis-adjusted, leaking etc. Either clamp off the heater cor water or bypass it completely & see what you get for vent temps.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

mk378 on Tue May 20, 2008 11:49 AM User is offline

In the driving test, the compressor should have been cycling normally on evaporator temperature. Is it icing up?

m32825 on Tue May 20, 2008 9:23 PM User is offline

>Make sure that the condensor is well coupled to the radiator, so that the fans draw air
>through it. A bit of foam rubber can really help this.

Good call, there was .5" to 1.5" of space between them around all edges. I framed the condenser with foam and measured again, the pressures were better:

At 1000 rpm:

low: 30 - 40 psi
high: 200 - 225 psi
vent: 62F

At 2000 rpm:

low: 22 - 32 psi
high: 225 - 250 psi
vent: 60F

Ambient temperature 82F, relative humidity 60%.

>Your bigger problem appears to be re-heating. ...
>Either clamp off the heater core water or bypass it completely & see what you get for vent temps.

I used a couple aluminum blocks and a welding clamp to pinch it off good, no change in pressures. Also tried running the blower with no a/c and I'm not feeling any heat.

What's next?

-- Carl

m32825 on Tue May 20, 2008 9:27 PM User is offline

>In the driving test, the compressor should have been cycling normally on evaporator temperature. Is it icing up?

I don't think so. I never got any vent temperatures beneath the low 60s (guess) and air flow was constant the whole trip.

m32825 on Wed May 21, 2008 10:33 PM User is offline

>With a low side of 15 to 25 psi, something is getting very cold. If the evaporator is flowing
>normally, then the air is picking up heat from the heater core.

Okay, we've eliminated the reheat and airflow possibilities. Could it be anything else at this point other than too much oil, which is reducing the system's ability to move heat from point A to point B?

bohica2xo on Thu May 22, 2008 3:21 AM User is offline

Carl:

I went straight for the low hanging fruit, and got a few. Always best to look for the exterior stuff first.

Excessive oil and or air in the system are likely culprits. Your latest Low side pressures say the TXV is working, but that 15 psi figure you posted makes me wonder a bit. If you see a lot of pressures below 20 psi, you may have a TXV that is not right.

It looks like you will be opening the system to get the excess oil out. If there was 3 ounces in the compressor, and you put six in...

You could flush, and go back to a known quantity. I can't recall if your nippondenso compressor has a bottom switch port. If it does, you could recover the system, and see how much oil is in the compressor sump by draining it. Since you put 6 ounces in, if you get two back this way you could close it up and re-test.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

m32825 on Thu May 22, 2008 1:10 PM User is offline

>I went straight for the low hanging fruit, and got a few. Always best to look for the exterior stuff first.

I agree, and I'm glad we did that. It's going to give me better performance all around once we nail this other issue.

>It looks like you will be opening the system to get the excess oil out. If there was 3 ounces in the compressor, and you put six in...

I got the compressor through www.ackits.com, would they be able to tell me how many ounces it shipped with?

>I can't recall if your nippondenso compressor has a bottom switch port.

Yes, rotation sensor on the bottom.

>If it does, you could recover the system, and see how much oil is in the compressor sump by draining it. Since
>you put 6 ounces in, if you get two back this way you could close it up and re-test.

Good plan, I'll give that a try. If I see better performance, then I feel more confident that time spent flushing won't be wasted.

I took a thermodynamics class in college, but working on my own a/c has taught me more useful stuff than the textbook ever did!

-- Carl

bohica2xo on Thu May 22, 2008 1:22 PM User is offline

Carl:

Unfortunately the compressor is a wildcard. I wish there was a standard shipping condition of "empty" with compressors, but I have seen them both ways.

Be sure you measure what you pull out of the compressor when you drain it.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

m32825 on Sat May 24, 2008 12:18 PM User is offline

>Be sure you measure what you pull out of the compressor when you drain it.

I got 50 grams, which I calculate to be about 1.7 oz. Here's the new data:

At 1100 rpm:

low: 38 - 40 psi
high: 265 - 270 psi
vent: 64F

At 2000 rpm:

low: 29 - 31 psi
high: 270 - 275 psi
vent: 60F

Ambient temperature 90F, relative humidity 56%. Here's what I'm getting driving at 2000 rpm with recirculation:

low: 22 - 26 psi
high: 190 - 210
vent: 53F

It's hotter today than when I took my previous (evening) measurements. Looks to me like cooling performance improved some, the vent temp while driving feels cooler now, though still not acceptable.

Two observations: 1) though it's nowhere close to clear, there's a little less foam in the sight glass, and 2) the pressures are cycling through a narrower range than before.

What do you think, a step in the right direction?

-- Carl

TRB on Sat May 24, 2008 2:02 PM User is offlineView users profile

Pressures look to be a little high. Need to be sure on refrigerant and oil capacities. If those are correct you need to check for proper air flow across the condenser.
-----------------

Compressor Type Nippondenso 10-Cyl.
Compressor Air Gap 0.0141-0.0259 in. (0.36-0.66mm)
R-12 Capacity 21-27 oz.
Compressor Oil Capacities 2.0-3.4 oz.
Normal Operating Pressures
Low Side 21-28 psi (1.5-2.0 kg/cm2 )
High Side 206-213 psi (14.5-15 kg/cm2 )
A/C Belt Tension 120-140 lbs. (54.5-63.5 kg)

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

bohica2xo on Sat May 24, 2008 2:15 PM User is offline

It sure looks like you have too much oil. Removing 1.7 ounces shifted things about what I would expect if there was about 10 ounces in the system...

Looks like it is time to remove some oil. You can't just keep draining the compressor, you will have no idea where you are at.

Luckily the dryer is less than 10 bucks, so it can just be replaced. You should be able to clear the serpentine evaporator with high velocity air. This means a good connection that can deliver 15 CFM @ 100 psi. A couple of 20 second blasts like that should get the excess oil out of the evaporator.

Clearing the PF condensor will be a bit harder. HECAT & Tim may have some suggestions to add to this, but I recomend removing the unit, and using blasts of high velocity air while manipulating the unit to work the oil toward the discharge - sort of like a marble in a maze.

I would put the system back together with the lower end of the oil charge in mind, since you will not get all of it out easily.

I hesitate to use solvents unless you are sure you can get them all out of the condensor. Of course if you have a quart of trichlor hiding in the garage...

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

TRB on Sat May 24, 2008 2:27 PM User is offlineView users profile

Total oil capacity should be close to 6.5 ounces.

I agree on flushing and leaving any solvent and/or flushing agent behind in the system. My opinion is flushing is a very important part of a/c repair. But if you fail to do it correctly it creates a bigger mess.

Brad, sent you a some PDF's. It's a pretty large file so if it bounces I'll set something up differently.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Sat May 24, 2008 at 2:28 PM by TRB

bohica2xo on Sat May 24, 2008 10:29 PM User is offline

Tim:

Thanks for the files. I thought the Mitchell number looked a little low @ 2 ounces, but with only 21 ounces in the system...

6 ounces seems like a lot, (25% of the refrigerant) but OK. It appears he has about double that quantity in the system. We already worked through the airflow issues, so it is down to charge level & oil quantity.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

m32825 on Sun May 25, 2008 9:47 PM User is offline

Okay, I'll plan on taking the system apart and flushing it. I'd like to take it somewhere and have an A/C shop do the flush to make sure it's thorough. Two questions:

1) What questions should I ask to make sure I pick a shop that will do it right?
2) About what should it cost, given that they don't have to disassemble/reassemble anything?

-- Carl

m32825 on Sun June 01, 2008 9:34 AM User is offline

Okay, it's apart:

Picture of A/C system dissection

You know, the second time around is a snap compared to the first time...

I'm going to drop it off at an A/C shop in the morning, they quoted me about $40 to flush it. Aside from "get the oil out" and "get the flush out", is there anything else you would add?

-- Carl

m32825 on Mon June 02, 2008 11:07 PM User is offline

I carried my parts down to the shop I called last week to get them flushed... I learned that you should always talk to the person who is going to be doing the work. They said they won't work on parts that aren't on a car, but, get this: they offered to do a flush if I would put all the parts back on... Kind of them to offer, but I passed. So now I'm in the flush it myself camp. Based on reading posts I'm picking up some mineral spirits and going after it later this week.

-- Carl

HECAT on Tue June 03, 2008 9:48 AM User is offline

I find the shops stand on only flushing the components installed in the car ludicrous, given the components are removed; they become easier to flush and confirm complete solvent removal. Being able to move the component around (Bohica's marble analogy), allows for the flushing process to be more effective.

I second Bohica and TRB's comments regarding the need for flushing, the hazards of solvent flushing, and that it can be done. But done improperly will cause more problems than it will solve.

Mineral Spirits, lacquer Thinner, Brake Cleen, and other commercially available cleaning solvents will work, but you must be aware that they sometimes contain many different chemicals with different boiling points and evaporative nature, as well as sometimes containing components that do not evaporate so well or may be incompatible with any seals and hoses (if exposed to flushing agent).

Mineral Spirits would be an excellent choice for flushing out mineral oils as the most common trace residue remaining after drying, would be mineral oil base. Although a little more expensive, a commercially available solvent flush specifically designed for flushing A/C PAG would be recommended. Make sure it is solvent based (not oil based), obtain an MSDS and confirm all contents are 100% volatile (evaporative).

As this is oil removal only, and the components are removed, you may have success with a pour in method (if you do not have any flush equipment). You can add agitation to this cleaning process by using a method Nick mentioned before... "shake the hell out of it". Follow the solvent with high CFM air flow for approx 20-30 minutes, to dry out the component. Make sure the air is filtered well as adding moisture and oils from your compressed air system is going the wrong way toward "Clean & Dry"

To test, use a "popping" method by adding air pressure to the component with your finger/thumb over the other port (careful not to allow to much pressure to build up), the release your finger/thumb; the sudden rush of escaping air will contain oils or solvents if they are still present. If they are, more work and diligence is needed until this test confirms "Clean & Dry"

-------------------------



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