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If you could pick an oil for a virgin install, which one would it be?

jsmitty on Wed March 25, 2015 6:26 PM User is offline

Year: 1986
Make: Mercury
Model: Grand Marquis
Engine Size: 302
Refrigerant Type: TBD ...
Ambient Temp: n/a
Country of Origin: United States

So, after 7 years of mickey mousing this system, I've decided to gut it all, replace it with new (including evaporator), and start from scratch. Last accumulator install got cross-threaded, and twisted/tweaked the evap outlet a bit, and is the source of my last leak. Compressor was getting noisy after too long of a run on Freeze 12 with a small spring joint leak. Still works, but at 220k miles, it may be time to retire it. I'll be buying everything here (aside from the liquid line, which isn't available here) once the weather starts to warm up in another 6-8 weeks.

Just curious what the guru's opinions are on this. If you could pick any refrigerant oil (and refrigerant, just to make it even more interesting) which one would it be and why?

I'm leaning toward R12 & ester. The system was designed for R12, #1, and #2 the molecular size, coupled with modern barrier hoses and lower pressures (vs. 134a) would keep the charge in for the longest possible time. Only downside is the cost. On the oil side of things, even though I see there is a DEC PAG, I think I'd rather have the better resistance to moisture of the ester. What are your thoughts on this? Do I not understand the DEC properties, or ..?? I want to do this ONCE, and not have to top off every x amount of months or even years - 8 years I could deal with .. but 1 year, no. We've owned this car for 12 years now, and I expect to keep it going another 12, at a minimum. We don't drive it in winter, so she's going to be resting in the barn for another month or so. Car is in excellent shape for this part of the country. It's 99.5% rust free.

If it were legal, I would probably try out an HC refrigerant of some sort, due to the performance/cost ratio ... although this doesn't seem to be the best bet for longevity, due to it's molecular sizing and ability to get past any porousity. Again, correct me if I'm wrong on this ...

I've learned so much over the years reading everything on this forum, and applying it out in my barn, and look forward to the responses. THANKS!

Cussboy on Thu March 26, 2015 9:37 AM User is offline

I suggest what I still use in my 1988 Mazda B2200 truck with 204K miles, here in Arizona: R-12 and mineral-type refrigeration oil. I just replaced its 11-year-old rebuilt compressor last October (seized) with a brand-new compressor from site sponsor AMA.

The R-12 cost is a one-time charge, will cost less than $50 difference overall than a "different" refrigerant, and remember that refrigerant is not a consumable, stays in unless there's a leak.

Edited: Thu March 26, 2015 at 9:39 AM by Cussboy

jsmitty on Thu March 26, 2015 10:52 AM User is offline

This is true. Only reason I was leaning towards ester is a just-in-case scenario - if I were to switch to 134a waaaay down the road, it would make that process much easier.

I've got 50 lbs. of the stuff ... and no R12. Still juggling if I'm going to spend the money on R12 or not.

Can you use 134a to check for leaks before adding R12, or is that a no no?

Edited: Thu March 26, 2015 at 10:53 AM by jsmitty

Cussboy on Thu March 26, 2015 1:57 PM User is offline

Originally posted by: jsmitty
Can you use 134a to check for leaks before adding R12, or is that a no no?


jsmitty on Thu March 26, 2015 2:04 PM User is offline

Sweet - thanks man. I appreciate the info.

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