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Old 05-03-2009, 07:02 AM   #1
alpinewhite318i
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Default Ester or PAG oil in rebuilt R134 compressor?

Does anyone know if I should be using ester or pag oil in a bmw rebuilt r134 seiko compressor?
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Old 05-03-2009, 08:05 AM   #2
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http://www.sadik.net/nissan/howto/ac_r12.htm

While both lubricants are used with R-134a, Ester is believed to be better for Retrofit systems because they are much less hygroscopic, which means that they don't absorb as much water from the atmosphere as PAG Oils do. This moisture can create problems in a vehicle's A/C system. Ester is also a truly Universal lubricant which has a Single Viscosity. PAG Oils come in a variety of viscosities which must be matched to the vehicle. GM vehicles use a high viscosity (150) PAG Oil, and non-GM vehicles use a low viscosity (46) PAG Oil. You cannot use a 100 viscosity PAG Oil as a "1 size fits all" universal lubricant. Ester Oil, however, is truly universal and will lubricate properly regardless of viscosity.
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Old 05-03-2009, 11:15 AM   #3
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PAG is a better oil, but it makes a corrosive mixture if mixed with any remaining chlorine in the system left over by the R12. When you retrofit, if there's any mineral oil left in the system there could be some chlorine trapped in it. POE (ester) oil can mix with the mineral oil, but not the PAG.

If you're doing a R12->R134a retrofit I recommend Double End Capped PAG oil. DEC-PAG oil has a double end capped oil molecule that won't have the bad problems relating PAG to chlorine. It's a better oil.
http://www.autoacforum.com/messagevi...threadid=17571
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Old 05-03-2009, 04:06 PM   #4
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How much oil should I be adding to the system? I am installing a brand new factory rebuilt R134 Seiko compressor, it didn't have any oil in it.
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Old 05-05-2009, 11:42 PM   #5
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None of the lubricants that are compatible with R134a come close to the performance of mineral oil. So you want the best of the available choices, and that means PAG.

You must clean out the system to use PAG oil. A rebuilt compressor (and of course a fresh drier) is the biggest part of the cleaning. A solvent rinse/flush of the other parts, done individually, is better.
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Old 05-06-2009, 08:40 AM   #6
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I was going to use ester oil that is capatible with both r12 and r134. Anyone know how many ounces are needed in the system?
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Old 05-06-2009, 12:04 PM   #7
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It depends on the compressor, 6-8 ounces is a good range.
For others reading this: make certain that your compressor doesn't already have oil in it -- double the oil in a system is far too much.

64 01 90 (3042) Apr 1990 Refrigerant and oil capacities
Refrigerant Oil
Swash plate (NipponDenso 10P15e) 120cc / 4oz, or 220cc w/ M42 (120 is likely a mis-print)
Seiko Seiki (BMW sourced retrofit) 220+-20 7.5oz oil
Behr-Bosch rotary vane 200+-20 / 7.0oz oil

For R12 they recommend the following mineral oils
Suniso 5GS; Shell Clavus G-100; Jidemitso D-90PX

Last edited by DJB : 05-06-2009 at 01:10 PM.
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Old 08-03-2009, 01:01 PM   #8
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so should i add the oil to the compressor first then vaccum, or first vacuum then shoot oil then freon?
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Old 08-03-2009, 01:36 PM   #9
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If you add oil from a bottle (by pouring it into the top of the compressor) then you have to do that before vacuuming. If you use the canister of oil, to be added via hose on the low pressure side, then you would add that after you vacuum. I don't like the 2nd method considering you will be running the compressor to suck refrigerant in while charging. The compressor won't be properly lubricated during this time because the oil won't yet be in the compressor.

I recommend:
1) pour the necessary amount of oil in the compressor inlet hose fitting.
2) Vacuum the system.
3) Add refrigerant to vacuumed system, as much as the system will take.
4) start engine and AC and let compressor pull down low side pressures while adding remaining refrigerant.

You never let any air back into the system after it's been vacuumed.
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Old 08-04-2009, 12:01 PM   #10
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Quote:
Originally Posted by bearing01 View Post
If you add oil from a bottle (by pouring it into the top of the compressor) then you have to do that before vacuuming. If you use the canister of oil, to be added via hose on the low pressure side, then you would add that after you vacuum. I don't like the 2nd method considering you will be running the compressor to suck refrigerant in while charging. The compressor won't be properly lubricated during this time because the oil won't yet be in the compressor.

I recommend:
1) pour the necessary amount of oil in the compressor inlet hose fitting.
2) Vacuum the system.
3) Add refrigerant to vacuumed system, as much as the system will take.
4) start engine and AC and let compressor pull down low side pressures while adding remaining refrigerant.

You never let any air back into the system after it's been vacuumed.

thanks for the insight, ill shoot oil after the vacuum, i got the compressed oil. i guess ill just have to be quick with it, to prevent damage to the compressor.
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