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Best place to add oil

azsimonsez on Fri January 18, 2008 12:28 AM User is offline

Year: 1992
Make: Toyota
Model: Previa
Engine Size: 2.4
Refrigerant Type: R12
Country of Origin: United States

I had to replace a manifold gasket on my 92 Toyota Previa. While I had it torn apart I went ahead and replaced the evaporator, expansion valve, put in new o rings and schrader valves. I will replace the receiver dryer when I'm ready to evacuate and add R12 freon.

The manual says to add about 2.5 oz of oil to the compressor when these parts are replaced. Should I add all of this oil directly to the suction port of the compressor before I add the freon or is there a better place to add the oil (like maybe the valve on the low pressure hose)?

Is there anything else I should do before I refill it?

NickD on Fri January 18, 2008 5:18 AM User is offline

I know what the manual says about replacing X amount of oil if you just replace the receiver, evaporator, condenser, or the compressor, but based on the theory the components you didn't replace still have an X amount of oil left in them. And your oil and receiver are already 16 years old. Since you already have gone that far, would flush how the compressor with new oil and drain it plus flush out the condenser and replace the receiver, then add in the full amount, that way you know for sure your system has the correct amount. Just pour all the oil in the condenser, still have an oil coating in the compressor, and it will mix fast when charging with little chance of oil slugging the compressor. If you want to be extra safe, hand turn the compressor by hand about 20 times. In new car manufacture, they just dump in all the oil in the high side port in one quick shot after a vacuum is drawn.

GM Tech on Fri January 18, 2008 8:27 AM User is offline

Actually in OEM applications the whole oil charge is "dumped" into the compressor low side (if fixed dsiplacement compressor) and compressor crankcase (if variable displacement) by the compressor manufacturer- the only thing the assembly plant does after system assembly, is add the refrigerant on the high side after pulling a vacuum and checking for vacuum decay. The oil stays in the compressor until it is run- all other system components and lines are bone dry............I've been to several assembly plants to witness this.......

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

ice-n-tropics on Fri January 18, 2008 9:20 AM User is offline

Quote
Originally posted by: GM Tech
Actually in OEM applications the whole oil charge is "dumped" into the compressor low side (if fixed dsiplacement compressor) and compressor crankcase (if variable displacement) by the compressor manufacturer- the only thing the assembly plant does after system assembly, is add the refrigerant on the high side after pulling a vacuum and checking for vacuum decay. The oil stays in the compressor until it is run- all other system components and lines are bone dry............I've been to several assembly plants to witness this.......

10-4, one slight exception is scroll compressor oil. 1/2 of the initial quanity goes into the suction and the other into the discharge cavity.
Also, some of the really big systems like 6 lb of R-134a in a CAT have to finnish the last portion of charging on the suction side with vapor.
Cordially,
Old IV guy

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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

NickD on Fri January 18, 2008 10:59 AM User is offline

Anything wrong about my recommendation to azsimonsez about draining the compressor, flushing it with oil, flushing out the remaining components and dumping the recommended amount of oil in the condenser to be assured he has a clean system and the correct amount of oil? Oh, and replacing the receiver as well.

azsimonsez on Fri January 18, 2008 3:46 PM User is offline

I flushed the condenser and dried it out with compressed air. I forgot to mention that while I was fixing the manifold gasket I took the compressor off and attempted to drain it. It doesn't have a drain so i turned it over and cranked it a little to try and get the oil to come out of the manifold ports. Very little oil came out of it. Does this mean I have a "scroll compressor"? It's a Denso 10PA17E.

So, now it needs about 4 oz or so of oil. Should I add it to the condenser or maybe half in the condenser and half in the compressor?

Thanks for the help all of you have given me. I'm a noobie at ac repair, but it makes me feel good when I do something myself and save money at the same time!

Chick on Fri January 18, 2008 3:54 PM User is offlineView users profile

Your Previa uses the Denso compressor, not a scroll.. You can add half back to the compressor, rest in the drier, or anywhere else.. You can add it all to the compressor, but if you do, it's not a bad idea to turn out the outer clutch a dozen or so times to move excess out into the lines.. The main thing is you don't want to start the system with a dry, or semi dry compressor.. Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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