Replace all PAG oil after fixing 2 year old leak?

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karlb
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Joined: Tue Jul 10, 2018 7:57 pm

Replace all PAG oil after fixing 2 year old leak?

Postby karlb » Tue Jul 10, 2018 8:16 pm

Finally got to replacing the front evaporator on a 4th gen (2004) Chrysler minvan. The dash pull was fun (not!).
t stopped working 2 years ago (oil on evap core and a bit in housing confirmed it was leaking). so let's call it an open system for 2 years. The new evap needs 50ml/2 oz of PAG46 added. Will be replacing the dryer/accululator as well (25ml/1oz more). Still seems like a lot of PAG full of moisture in the system.
But given that PAG is hygroscopic and the system has been open this long, it is worth the effort to pull the compressor, condenser and rear evaporator (has rear a/c) to drain and refill the oil in those? I'm guessing another 6 hours R&R those. The lazy answer is no, but what's the right answer?

Thanks in advance!
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bohica2xo
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Location: Las Vegas, NV

Re: Replace all PAG oil after fixing 2 year old leak?

Postby bohica2xo » Tue Jul 10, 2018 9:43 pm

Flushing all of the old PAG out is the best job you can do.

A 14 year old car probabbly has a far bit of miles, and you should probably clean all of the old PAG out.

Was there a line disconnected or just the pinhole in the evaporator?

Just remember that there is no limit to how much water PAG can soak up - unless it is DEC type (which was NOT used in that van when new)

https://www.autoacforum.com/messageview.cfm?catid=20&threadid=17571

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karlb
Posts: 3
Joined: Tue Jul 10, 2018 7:57 pm

Re: Replace all PAG oil after fixing 2 year old leak?

Postby karlb » Wed Jul 11, 2018 11:16 am

Thanks! I figured that was the right answer.

Was just a leak in the evaporator, but it's been empty for 2 years, so certainly time for moisture to accumulate in the oil. Thanks for the link on regular PAG vs. DEC PAG moisture absorption; didn't realize it was that hygroscopic.
I'm thinking I should look at the condenser while I'm at it. It's not very hard to take off, and given that this van is 14 years old, I can imagine it leaking right after I'm done this. And it's also around the time for the radiator to give out. Sigh, while I'm at it... :lol:

Now to find DEC PAG46 here in Canada. It shouldn't be this hard (Carquest will take a week or more to get, Grainger needs an order of 12 bottles, NAPA doesn't know what DEC is. Amazon just has 3rd parties at inflated prices.) :roll:
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bohica2xo
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Location: Las Vegas, NV

Re: Replace all PAG oil after fixing 2 year old leak?

Postby bohica2xo » Wed Jul 11, 2018 11:50 am

Yeah, I dispose of unused SEC PAG by mixing a couple ounces in to a pint of water - and put it in a pump sprayer next to the drill press. Makes good cutting oil.
karlb
Posts: 3
Joined: Tue Jul 10, 2018 7:57 pm

Re: Replace all PAG oil after fixing 2 year old leak?

Postby karlb » Thu Jul 12, 2018 6:48 pm

Isn’t my local Carquest great? :lol:
Yesterday the only PAG-46 was more than a week away. Today the next shop over has it and I should get it in a day or two. Supercool PAG.

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