Date: Fri, 5 Aug 2016 00:42:00 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Whining AC compressor
In-Reply-To: <CA+az7_7YiWo=vG=-PC=F-YZHeQkM-cpvBTX-1nbsz5JaQJEiGA@mail.gmail.com>
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Did flushing the system also include removing the compressor and removing the drain plug on it and actually draining it out. If not then there was still the R12 mineral oil and probably the best choice would have been the Ester oil or one of the specialty oils used for R12 to R134a conversions. The PAG oil can react over time and create a jelly or globule like mess in there.
Since refrigeration oil will not travel through the desiccant dryer, there is a bypass hole in there for the accumulated oil to travel through so it can go back the compressor. Too much oil in the system or this hole getting blocked with that mess mentioned early will block the works and starve the compressor of oil. The excess oil in the system will cause over pressurization in a manner that the high pressure switch will not react fast enough and compressor damage can result. I also don’t know about the long term compatibility of the PAG oil with the HFC152a.
You also made some bad assumptions. When refrigerant leaks out it will take some of the oil with it. When refrigerant leaks out there is also some magic that even with some pressure remaining the system still manages to let moisture and other bad stuff in.
How did you add the PAG oil? If you used an R134a oil can kit you now have mixed (contaminated) refrigerant system. If you go to a shop to have the system recovered be sure to tell them that.
Sometimes these compressors just whine. There may be (was) a restrictor in the outlet hose to reduce this. Was this also the van that did not have the radiator fan working properly? Could just be bad luck or bad diagnostics and repairs finally got the better of it. From experience the only normal wear item on one of these compressors is the shaft seal, usually after many years of use. Almost anything that fails inside is due to something being done to it. Over/under charging, operating pressures, (condenser fan), contamination, lubrication.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Rodgers
Sent: Thursday, August 4, 2016 11:30 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Whining AC compressor
Larry, four years ago the system was flushed by a shop, PAG OIL added ( I don't know how much) using some reference they had, then serviced with R134a. It ran fine but over time slowly lost pressure until the pressure switch turn the system off. The system has never been opened since, and when I went to recharge it recently, it still has pressure, which meant the seals and oil should still be there, and oil should still be good, so no oil was added, the system was evacuated, and HFC152a added. The system worked super well, until last weeked, and the whine began to develop. Over several days it has gotten louder and louder. It sounds like a PS pump when it begins to run low on power steering fluid. Only its the compressor. I've decided to add 2 ounces of pag oil, maybe that will do the trick. If not, then it gets a new compressor, and the system drained, and flushed before the new compressor gets installed.
John
John
On Aug 4, 2016 17:40, "Larry Alofs" <lalofs@gmail.com> wrote:
> Was all the old mineral oil cleaned out of the compressor before the
> conversion? Any idea why PAG was used instead of ester oil?
> Were the amounts of oil added according to the Bentley recommendations?
>
> Larry A.
>
>
> On Thu, Aug 4, 2016 at 10:52 AM, John Rodgers <jrodgers113@gmail.com>
> wrote:
>
>> Is there a way to add more PAG oil to the system without venting and
>> draining the whole thing? I'd like to get through this summer heat if
>> possible and put a new compressor on for next year. Got about a month
>> to six weeks to go.
>>
>> John
>>
>> On Aug 4, 2016 01:52, "Dennis Haynes" <d23haynes57@hotmail.com> wrote:
>>
>> > It is possible your recent recharge did not include the correct
>> > type or among of oil to go with the refrigerant charge. Sometimes
>> > these
>> compressors
>> > do get noisy and they sometimes run this way for years. Sometimes
>> > they also self destruct and fill the system with pieces.
>> >
>> > Dennis,
>> > From my phone.
>> > ------------------------------
>> > From: John Rodgers <jrodgers113@GMAIL.COM>
>> > Sent: 8/3/2016 9:13 PM
>> > To: vanagon@GERRY.VANAGON.COM
>> > Subject: Whining AC compressor
>> >
>> > This on my '88 GL. Bloody ho in Alabama just now and badly needed.
>> > I recently serviced the system and it's been fine for about two weeks.
>> Then
>> > started with the whine that has gotten progressively louder. I hate
>> > it
>> but
>> > will have to run with it turned of. No experience with this. Anyone
>> > have any ideas. Really hate the idea of having to get a new
>> > compressor just
>> now.
>> > Pricey!
>> >
>> > Thanks.
>> >
>> > John
>> >
>>
>
>
