A/C Air Conditioning compressor bearing advice needed
05-17-2016, 08:46 AM
#16
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Personally I think the stock compressors are pretty good and a used one is a good option particularly in a cool country. They may not work well with R134A but they work well with R12 and mine seems to be happy with R152A (computer duster spray). I have read that R152A is the new stuff going forward and approved for vehicles in Europe, with a bunch of caveats of course and you probably cannot retrofit without a form 27B/6 filled out (in Belgian) then approved and stamped by Information Adjustments.
In a hot country you probably want to stack the deck with a Sanden and an upgraded condenser and all that.
-Joel.
In a hot country you probably want to stack the deck with a Sanden and an upgraded condenser and all that.
-Joel.
05-17-2016, 10:05 AM
#17
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1) Depending upon what country you live in, NO, you cannot vent the refrigerant into the atmosphere. You are suppose to have it "recovered" (pulled out).
After refrigerant recovery:
2) Loosen belt tensionor, disconnect from compressor. Remove AC drive belt. Disconnect refrigerant lines at compressor manifold. Remove top compressor sling bolts. Drop compressor (not on your head).
3) Locate a clean can and turn the compressor manifold port so it sits on the entrance to the can. Turn the outer clutch hub (not the pulley) several times and hope refrigerant oil (maybe 1/2 or more if you are lucky) drains into can. Use a 5x magnifier and exam the refrigerant oil for signs of contamination: fine metal particles, grey matter, wax'd oil). If you find debris you must liquid AC flush the condenser, refrigerant lines, evaporator with its expansion valve removed; you don't flush compressors, driers or expansion valves.
4) Install new drier and while you are at it replace all the system's o-rings.
5) Inspect the compressor to condenser refrigerant line for cracks or weaping by the ferrules; this line typically fails first, next if the condenser to drier line.
Also inspect your AC belt for signs of cracks.
6) You will need to put back in the system 6 oz of refrigerant if you have flushed the entire system, 4-5 oz if just replacing the compressor and drier.
Oil type: if the system was only R12, you can use 'ester' type oil. If the system was converted to R134a and you are not flushing the system clean, you'd want to determine what kinda of oil was used, ester or PAG and use the same.
7) If you purchase another compressor, dump its oil out before installing, properly dispose of that oil.
8) You could have refrigerant oil dye tracer injected prior to having the system recharged. Discuss this with your AC shop.
9) If you are going to put in a 'rebuilt, repaired, remanufactured' compressor, only put in a "Denso" unit, and it should come in a Denso box: meaning Denso did the work.
10) Have the system evacuated, charged, tested for leaks and performance.
944/968 AC
After refrigerant recovery:
2) Loosen belt tensionor, disconnect from compressor. Remove AC drive belt. Disconnect refrigerant lines at compressor manifold. Remove top compressor sling bolts. Drop compressor (not on your head).
3) Locate a clean can and turn the compressor manifold port so it sits on the entrance to the can. Turn the outer clutch hub (not the pulley) several times and hope refrigerant oil (maybe 1/2 or more if you are lucky) drains into can. Use a 5x magnifier and exam the refrigerant oil for signs of contamination: fine metal particles, grey matter, wax'd oil). If you find debris you must liquid AC flush the condenser, refrigerant lines, evaporator with its expansion valve removed; you don't flush compressors, driers or expansion valves.
4) Install new drier and while you are at it replace all the system's o-rings.
5) Inspect the compressor to condenser refrigerant line for cracks or weaping by the ferrules; this line typically fails first, next if the condenser to drier line.
Also inspect your AC belt for signs of cracks.
6) You will need to put back in the system 6 oz of refrigerant if you have flushed the entire system, 4-5 oz if just replacing the compressor and drier.
Oil type: if the system was only R12, you can use 'ester' type oil. If the system was converted to R134a and you are not flushing the system clean, you'd want to determine what kinda of oil was used, ester or PAG and use the same.
7) If you purchase another compressor, dump its oil out before installing, properly dispose of that oil.
8) You could have refrigerant oil dye tracer injected prior to having the system recharged. Discuss this with your AC shop.
9) If you are going to put in a 'rebuilt, repaired, remanufactured' compressor, only put in a "Denso" unit, and it should come in a Denso box: meaning Denso did the work.
10) Have the system evacuated, charged, tested for leaks and performance.
944/968 AC
I converted my '88 924S from R12 to R134a a couple of weeks ago.
I purchased a remanufactured "Denso" unit.
I replaced the receiver dryer.
I used 'esther" oil-----it is the yellow (ish) color. AutoZone. Will mix with old oil in the system the best.
8 ounces is enough. I put about 4 in the compressor, 1+ in the R/D, and about 2 in the condenser.
You need 6 O-rings---2-compressor, 2 receiver dryer, 2 condenser.
AutoZone has a small kit of green O rings for $5.99 (lube before installing).
I flushed the condenser---contamination settles in the lower coils.
AutoZone has a pressurized can of flush for about $16. Enough for the condenser. I flushed from top of the condenser to bottom until I ran out of flush. Filthy.
I charged the system with R134a--only about 20 ounces---much less than is called for.
The +-28 YO A/C system on the '88 is holding a charge and cooling, not the same as R12 but sufficient at temps under 105.
J_AZ
05-17-2016, 10:36 AM
#18
The issue with companies other than Denso attempting to 'rebuild, repair, remanufacture' the Denso compressor is they usually don't use new parts:
compressor bores, pistons and wobble plate. You can only get that with a Denso reman in a Denso box, reman'd by Denso.
944-968 Compressors
05-17-2016, 11:47 PM
#19
Burning Brakes
Agree on the reman Denso. Most reman are junk and fail after a year or two.
Also, check the high pressure hose from the compressor to the condensor. Clean it off and feel along the entire length for any bumps or abnormalities. You may want to consider replacing it as a preventative measure. It is the most highly stressed hose in the system (pressure & temperature) and likely to fail, especially after rebuilding the system and having proper, although higher, pressures.
Also, check the high pressure hose from the compressor to the condensor. Clean it off and feel along the entire length for any bumps or abnormalities. You may want to consider replacing it as a preventative measure. It is the most highly stressed hose in the system (pressure & temperature) and likely to fail, especially after rebuilding the system and having proper, although higher, pressures.
05-21-2016, 12:17 PM
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Thanks guys, this help is amazing!! I'm glad I asked before getting stuck in!
As far as the o-rings go, looking at the schematics, I see the 2 o-rings on the drier, 2 on the lines which run into the top of the compressor, where are the other 2 mentioned?
If someone can help point me in the direction of a kit that would be great, the individual prices of the o-rings from Porsche are way more than the price mentioned here from AutoZone.
As far as the o-rings go, looking at the schematics, I see the 2 o-rings on the drier, 2 on the lines which run into the top of the compressor, where are the other 2 mentioned?
If someone can help point me in the direction of a kit that would be great, the individual prices of the o-rings from Porsche are way more than the price mentioned here from AutoZone.
05-21-2016, 12:33 PM
#21
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The other 2 O-rings are the ones on the lines going in and out of the condenser. I just take the O-rings out and go to a local auto parts and match the size. I always buy the HSN/HNBR O-rings (green ones).
05-21-2016, 12:38 PM
#22
For AC what is used is a standard "#" (number) size descriptions.
For your year and model you need:
#10 = 2 (evap to comp)
#8 = 3 (comp to cond and 1 under TEV)
#6 = 4 (cond, drier and 1 at TEV)
There are o-rings under pressure switches (depending upon the year) however chances of a leak there are nominal.
The R134a compatible compound HNBR (Hydrogenated Nitrile Butadiene Rubber) or HSN (Highly Saturated Nitrile) can come in an array of colors,
certain o-ring mfg's color code their o-rings (the most common HNBR is green); I've seen blue, green, and black (although black was the OEM NBR).
You will typically find green HNBR.
You could shop around for separate o-rings, you could buy a "R134a kit" for your car or if you just need a reasonable o-ring kit of sorts here is on over at
Pelican
With regard to putting in the refrigerant oil, you do not have to put the oil in each of the components, that is tedious. After the system has run for a few moments the oil gets spread throughout then entire system. There are a few ways to get the total amount needed into the system, for example:
1) Put it all in the compressor, after you connect hose lines to compressor you rotate the outer clutch hub (attached to comp shaft) a dozen times to push it out of the compressor so its not liquid slugged.
2) Pour it in the comp outlet line.
3) If you are having the system professionally evacuated and charged they can inject the correct amount.
For your year and model you need:
#10 = 2 (evap to comp)
#8 = 3 (comp to cond and 1 under TEV)
#6 = 4 (cond, drier and 1 at TEV)
There are o-rings under pressure switches (depending upon the year) however chances of a leak there are nominal.
The R134a compatible compound HNBR (Hydrogenated Nitrile Butadiene Rubber) or HSN (Highly Saturated Nitrile) can come in an array of colors,
certain o-ring mfg's color code their o-rings (the most common HNBR is green); I've seen blue, green, and black (although black was the OEM NBR).
You will typically find green HNBR.
You could shop around for separate o-rings, you could buy a "R134a kit" for your car or if you just need a reasonable o-ring kit of sorts here is on over at
Pelican
With regard to putting in the refrigerant oil, you do not have to put the oil in each of the components, that is tedious. After the system has run for a few moments the oil gets spread throughout then entire system. There are a few ways to get the total amount needed into the system, for example:
1) Put it all in the compressor, after you connect hose lines to compressor you rotate the outer clutch hub (attached to comp shaft) a dozen times to push it out of the compressor so its not liquid slugged.
2) Pour it in the comp outlet line.
3) If you are having the system professionally evacuated and charged they can inject the correct amount.
05-21-2016, 07:33 PM
#23
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Thanks Griffiths,
I now understand how you can install all the oil in the compressor-----"-if you rotate the outer clutch hub a dozen times to push it out of the compressor...."
http://www.denso.ua/media/27142/dens...ion-manual.pdf
John
I now understand how you can install all the oil in the compressor-----"-if you rotate the outer clutch hub a dozen times to push it out of the compressor...."
http://www.denso.ua/media/27142/dens...ion-manual.pdf
John
05-22-2016, 03:12 PM
#24
John,
The Denso pdf has some good and not so good information:
BS #1
"In general all original DENSO Compressors are delivered with the correct amount of oil. Adding oil or removing oil is, in almost all cases, not necessary."
It is impossible for any compressor manufacturer to know how much oil your system has in at any given time other than when the vehicle was first manufactured.
BS#2
"Never add oil directly into the compressor."
Well I guess that means its okay for Denso to do it but you aren't old enough to do it, lol.
The Denso pdf has some good and not so good information:
BS #1
"In general all original DENSO Compressors are delivered with the correct amount of oil. Adding oil or removing oil is, in almost all cases, not necessary."
It is impossible for any compressor manufacturer to know how much oil your system has in at any given time other than when the vehicle was first manufactured.
BS#2
"Never add oil directly into the compressor."
Well I guess that means its okay for Denso to do it but you aren't old enough to do it, lol.
05-23-2016, 12:48 PM
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Thanks again everyone, I've ordered a reman compressor now. I will also try find a drier and some o-rings and order them.
All this expense to do the job properly! When I started out I thought I'd found a clever way of fitting a new bearing on the compressor without disconnecting the a/c lines all just for $10 (I had) but I'm told it is leaking just behind the pulley from the garage.
All this expense to do the job properly! When I started out I thought I'd found a clever way of fitting a new bearing on the compressor without disconnecting the a/c lines all just for $10 (I had) but I'm told it is leaking just behind the pulley from the garage.
05-26-2016, 07:44 AM
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Could I double check the procedure regarding the oil so I don't make a mistake.
I'll tip out the oil from the old compressor and inspect as mentioned.
I've bought a recon unit, which will come with oil. Am I supposed to tip this out and measure the same amount as removed from my old compressor?
I have ester oil in my system at the moment.
The rest is pretty clear, just want to be sure I've got this bit right!
Thanks again!
I'll tip out the oil from the old compressor and inspect as mentioned.
I've bought a recon unit, which will come with oil. Am I supposed to tip this out and measure the same amount as removed from my old compressor?
I have ester oil in my system at the moment.
The rest is pretty clear, just want to be sure I've got this bit right!
Thanks again!
06-09-2016, 07:58 AM
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I got a proper Denso unit with a Denso box, and it came with an installation guide. I'll scan this in case it is useful for anyone.
The only thing I'm left confused about, is regarding the oil type. I have a reman compressor which has come with oil, but I don't know what time? My car has a stick on it saying it has ester when it was regassed. When I evacuate the system prior to fitting the new compressor, will this evacuate all the existing oil aside from that in the old compressor?
The only thing I'm left confused about, is regarding the oil type. I have a reman compressor which has come with oil, but I don't know what time? My car has a stick on it saying it has ester when it was regassed. When I evacuate the system prior to fitting the new compressor, will this evacuate all the existing oil aside from that in the old compressor?
06-09-2016, 09:00 AM
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I would find out what type oil is in the new compressor. If I could not then I would drain the oil and put 8oz of ester oil into the compressor. After installing the compressor and hooking up all the lines you want to rotate the compressor several times to push the oil out of the compressor into the system. You turn the outer part of the compressor clutch assembly.
When you vacuum the system it does nothing to the oil in the system, it only removes moisture.
When you vacuum the system it does nothing to the oil in the system, it only removes moisture.