AC questions

[Mustang5L5]

Yes, I know it's january and there is a nor'easter about to drop two feet of snow on me....but let's talk ac.

Putting the ac back in my fox. I was an idiot for removing it


Question #1. does anyone have a good rebuild/ technical data document on the nippon-denso 6P148A compressor?

Question #2.. Should I go r-12 or r-134a?

So I have all brand new parts. Here my list so far.

NEW
Evaporator
Accumulator + hose
Orifice tube line
Misc 3rd ac line
Condenser

Used
Ac/power steering accessory bracket + hardware
Compressor.

The compressor is used, but I actually took it off an r12 car recently with a working ac system. Ran fine, and I've inspected it internally with borescope and everything looks clean and corrosion free. I have confidence in it. I've vacuum sealed it for now to protect against moisture.

Problem I find is everyone has write-ups on r134a conversions, but I want to stay r-12. It's more efficient and runs cooler. Since all my parts are new, I need tom decide now what to use, but can't find info on r-12

What is the fill charge of r-12?

How much POE oil do I need?

The compressor was drained, but how do I know how much is currently inside? sanden gives some excellent info on it's compressor and estimated oil remaining on a drilled compressor, but I can't find anything on the Nippon-denso compressor. I need to find out how much oil I need to add total, as well as total r-12 charge.

I also need to change the two o-rings on the compressor and pick up a damn good vacuum pump.

Does anyone know if there are any caps I can use on the ac compressor to seal the suction and discharge ports? I want to put it on the car, but not let moisture get inside.

 

[ID89GT]

I would go R134 if it were me. It is so much cheaper and readily available at most parts stores. R12 is super high priced since they don't make it no more.

 

[jrichker]

To legally purchase R12, you will need to have an EPA 609 certification. That will cost about $20-$25 for the open book test & materials. See EPA Certification by Mainstream Engineering

For top performance R134 requires a condenser with a different design. The first thing you notice is thare are more fins per inch on the R134 condenser. Using the OEM R12 unit will reduce the performance in stop and go driving when you are stuck in traffic. The R12 style unit does not condense the R134 hot gas into a hot liquid effeciently.

R12 fill charge is 40 oz R12. The 8-10 oz of oil figure I am not sure of, but iti is close. There should be a sticker on the upper raditator mount crossbar with both oil and refigerant capacities.

Gauge set for recharging = $20-$120 – check out the pawn shops for a bargain before you pay retail.
http://www.harborfreight.com/cpi/photos/92600-92699/92649.gif

Vacuum pump – I use an old refrigerator compressor = $20- $40 at used appliance stores, or go to the Dump and get one for free. Be sure to have some R12 compatible oil handy to keep it lubed up properly.

Plastic tools to disconnect refrigerant lines - 1/2" & 5/8" = $4 each.

You will need a vacuum pump- mine is an old refrigerator compressor, so that all the air, vapor and moisture is removed from the system. Vacuum it down for about 30 minutes, this should give you about 28" of vacuum or more inside the A/C system. I have a vacuum gauge "T" connected into the vacuum pump line so that I can accurately watch the vacuuming process. This is a good time to take a soda and sandwich break since it doesn’t go faster if you watch it.

Flushing the compressor is only necessary if you do a R134 conversion. Here's what i did.
Disconnect the compressor and remove it from its mount to flush it with cleaning solvent. Pour about a cup of solvent into the suction port and turn the compressor center hub about 10 turns while shaking the compressor to move the solvent around inside the compressor sump. Drain the flushing solvent out and continue to turn the center hub by hand to force out any remaining solvent. Then fill it with oil: add about 8-10 oz of the new oil to the compressor large suction fitting. Turn the compressor center hub about 20 turns as you turn the compressor face up and face down to distribute the new oil inside the compressor. Catch and replace any oil that comes out of the compressor.


Remove the electrical connector from the dryer/receiver and jumper the two connections inside the wiring harness side of the connector together: this allows the compressor to engage in spite of low pressure/no gas in the system. Close both charging gauge valves, and then disconnect the center hose of the charging gauges from the vacuum pump and connect it to the R134a can tapper. Put the R134a can in the can tapper and screw it down with the can tapper valve closed, then open the valve. Loosen the hose at the center connection of the charging gauge set until the R134a squirts out: this purges the line of air and moisture. The refrigerant is added through the low pressure side of the system, so open the low pressure gauge valve to add the R134a. Start the car and take note of the idle speed, then set the idle speed up to about 1200-1500 rpm, and turn the A/C on inside and set the fan speed on high. Watch for the pressure on the low side to drop off as you are filling, and the R134a can will get warm and stay warm. This tells you the current can is empty and needs to be changed for a fresh one. Before you disconnect the can, be sure to close the valve on the R134a can tapper.

Remove the electrical connector from the dryer/receiver and jumper the two connections inside the wiring harness side of the connector together: this allows the compressor to engage in spite of low pressure/no gas in the system. Close both charging gauge valves, and then disconnect the center hose of the charging gauges from the vacuum pump and connect it to the R134a can tapper. Put the R12 can in the can tapper and screw it down with the can tapper valve closed, then open the valve. Loosen the hose at the center connection of the charging gauge set until the R134a squirts out: this purges the line of air and moisture. The refrigerant is added through the low pressure side of the system, so open the low pressure gauge valve to add the R12. Start the car and take note of the idle speed, then set the idle speed up to about 1200-1500 rpm, and turn the A/C on inside and set the fan speed on high. Watch for the pressure on the low side to drop off as you are filling, and the R12 can will get warm and stay warm. This tells you the current can is empty and needs to be changed for a fresh one. Before you disconnect the can, be sure to close the valve on the R12 can tapper.

Watch the high side pressure on the charging gages and regulate the adding of gas to keep the high side pressure under 350 psi. You will probably need a fan in front of the car to keep the readings below 350 psi. I had to put the R12 can in hot water while I was charging the system with it, or else the can got so cold that it quit flowing. Use caution when you do this so that you don’t get water in the charging adapter when you change the cans.

 

[Dachipsta]

I feel ya on wanting to keep the system r-12. Since that is what the entire system was designed around, it does in fact operate much more efficiently with 12. If 12 is readily available to you for whatever reason, then by all means keep the thing r-12. The only drawback to not converting is the cost of 12 when making repairs. Other than that, there really is no reason to convert.

If you do decide to stay with 12, what you have mentioned is all good except for the oil charge. You will want to use mineral oil with 12. All a/c systems are designed with the idea that the refrigerant will carry the oil around with it while running. If you use an oil not compatible with 12, the refrigerant wont carry the oil with it and the compressor will fail due to lack of lubrication. Make sure you use an oil that is compatible with r-12.

I forget the exact oil charge in oz. but you can do a search on the net and its out there. When I did my retrofit, thats how I found out what it was. I cant remember if the Nippedenso has an oil plug in the bottom that can be taken out to drain the sump of the compressor. That makes it easy when trying to determine how much oil is in the compressor. If the system was operating low on charge for any extended period of time then there prolly isnt much oil in the thing if any at all.

As far as the answer to the question as to whether or not to convert to 134, thats up to you really if you dont have any problems obtaining r-12. I could get my hands on it easily due to me being a commercial refr/air mechanic. Me personally, I was reluctant as to the idea of converting because I had heard all the stories of sitting in a traffic jam and having the air temp start climbing higher and higher until I was lucky if I was getting 80* air temps coming out of the dash vents....lol.

This is what I discovered. 1. The 134 systems have a higher capacity compressor....ie. the Sanden vs. the Nippo.
2. The condenser coil can handle more of a load than the one designed for R-12.
3. The metering device or orifice tube is a slightly different diameter which results in more efficicent cooling at slower compressor rpms.
4. The evaporator may be a different capacity as well but I am unsure about it so I wont say one way or the other.

What all this says is that the newer systems are designed around 134 vs. the older systems that have components designed to be used with R-12.

From what I have experienced when someone complains of bad performance from a 134a conversion one or more things were overlooked. The old, worn out 15+ year old compressor was utilized, the evap. and cond. coils were not flushed out in order to remove the exsisting refrigerant oil. A proper evacuation or vacuum was not obtained before adding the new refrigerant charge and/or a small amount of the existing refrigerant was left in the system when the new charge of 134 was added. Any one or more of these circumstances will cause a 134a conversion to operate poorly.

Hope some of this helped......l8r

 

[Mustang5L5]

Those are the exact reasons I want to stay r-12. For my investment into this project, I want to do itnright. I can get the r-12. It will cost me, but end result will be worth it.

I thought I had the type of oil wrong, but wasn't sure. I just need to find the quantities.

Don't think there is a drain on the compressor but I'll look again. It's still full of oil as it runs out when I tip it up. Still nice and clean which is why I am not worried about the compressors condition.

 

[Mustang5L5]

To legally purchase R12, you will need to have an EPA 609 certification. That will cost about $20-$25 for the open book test & materials. See EPA Certification by Mainstream Engineering .

For an open book test, it was a little tricky. 25 questions took me almost 2 hours to do...but i got 24 out of 25 right!

ANyway, now i'm 609 certified, which i needed because sellers on ebay were requesting it.

 

[Shaolin Crane]

Mike go with this kit, its cheap but has everything you'll need, i have serviced many vehicles using this kit
http://www.amazon.com/dp/B0029N4W7S/?tag=stangnet-20

 

[jrichker]

For an open book test, it was a little tricky. 25 questions took me almost 2 hours to do...but i got 24 out of 25 right!

ANyway, now i'm 609 certified, which i needed because sellers on ebay were requesting it.

I got my 609 certification when Mainstream Engineering first started doing the open book online test. I had a PDF doc with all the study course materials and a good search function. With those tools, it wasn't too hard. I am sure that it is much tougher now. Too many guys like me around have made them wise up...

 

[Mustang5L5]

I got my 609 certification when Mainstream Engineering first started doing the open book online test. I had a PDF doc with all the study course materials and a good search function. With those tools, it wasn't too hard. I am sure that it is much tougher now. Too many guys like me around have made them wise up...

Yeah it's a little tougher id imagine. I test pretty good, but for an open book test they worded things in a way that makes you have to read between the lines and interpret what they state in the manual. I had to go back over questions a few times. I definitely wasn't expecting that. I kinda thought it would be a pushover test. But I got it.

 

[Mustang5L5]

Mike go with this kit, its cheap but has everything you'll need, i have serviced many vehicles using this kit
Amazon.com: 2009 ATD AC Bag Kit ATD 90: Automotive

I actually have something similar to that for 134a. Buddy had a few kits and gave me one.

I really want to try to do r-12 here. Just gotta buy 40oz now

 

[giddyup306]

What, air compressors lock up in the winter too. Not only that, but on some vehicles they run during the winter to dehumidify the air...

Anyways I'd personally retrofit it to 134a. I have no clue what r12 is at now, but five years ago I was charging $80/lb. 134 is about 7 or 8 dollars. r12 does dissipate heat better, and the molecules are much bigger, but it's not worth the added cost. Hell, I've built AC systems in stretched limos and buses that have 134 and a single compressor, and they still cool well.

Also r12 is pretty hard to get, even if you have a 609 license. So what happens is people get stuff from questionable sources. There are several risks that you need to watch out for. A lot of this stuff is smuggled illegally from Mexico. Their tolerances aren't very tight, and they have a lot of moisture in it. You can use a refrigerant identifier, but I doubt you want to shell out $1,800 for one. If you go down to your local parts store and the can says DuPont on the side, then it probably has a high QC standard. Another thing you need to look out for is blends and mixes (such as Freeze 12). Not only will this contaminate your gauge set, some of them even contain propane! I don't know about every state, but as far as I know it is illegal to put propane in a refrigerant system in Nebraska.

 

[Shaolin Crane]

I actually have something similar to that for 134a. Buddy had a few kits and gave me one.

I really want to try to do r-12 here. Just gotta buy 40oz now

It has fittings for both....

 

[Boosted92LX]

Mike go with this kit, its cheap but has everything you'll need, i have serviced many vehicles using this kit
Amazon.com: 2009 ATD AC Bag Kit ATD 90: Automotive

That, sir, is a sweet kit. I believe I will order one.


I'm not professional at hvac, but I do my own just on my vehicles. I have a couple buddies who are ase mechanics and one who owns an a/c business who coaches me. One of my mechanic friends recently converted to 134a because of the ridiculous cost of 12. He flushed the old oil out of the system with spray solvent and a spray nozzle on an air hose with an air compressor. He swapped out the orifice tube, oiled it with 134 compatible oil and charged it with 134. That's all he did, and he swears it works just as well. He told me where people screw up is not changing the orifice... It won't be 100% efficient, but he says it's not bad enough to notice really.

I'll give it a shot in a few months and let you know how accurate that info really is....