85 GW - AC Rebuild and Conversion - Help w/Oil

[82Eagle]

Hey guys, hoping an AC guru can help me out..



I'm working on a rebuild and conversion to R134a of my factory AC system. When I got the Jeep two years ago the system was closed but empty. Found a twisted metal line at the condenser that was probably a slow leak. My York isn't in great shape so I found an old rebuilt Sanden SD-508 to install with the adapter mount. I am waiting on fresh barrier hose and fittings to adapt the Sanden and replace the old crusty R-12 lines. I have a new condenser, drier, expansion valve, switch/thermostat and compressor. The evaporator is not being replaced. I am also 86'ing the in-line sight glass while keeping the low pressure cut-off switch.



This being said I'm lost on oil fill capacities. I have the TSM but it offers about a sentence worth of content with oil. The Sanden may or may not have oil in it. If it does there is a chance it is mineral oil. It appears its sat for many many years on the shelf. It's still capped and pressurized from storage and I don't want to open it up just yet.



My plan is to drain any oil in the compressor and add Ester 100 oil instead of the recommended PAG (SP-20 / SP-15) so any residual mineral oil is accounted for. I'm just not sure how much. Sanden has charts showing what the compressor takes but I'm not sure if that accounts for what might be left in the rest of the system.


The entire front end of the Jeep is disassembled, AC unit is pulled completely, so now is the time. I am also wondering how long these new parts can sit connected but with no charge/vacuum pulled and remain ok.


THANKS!

[wiley-moeracing]

First, check on the proper oil, may be pag 46? Second , you need to replace the condenser if your doing the conversion, third, flush the entire system and make sure it is clean of any old oil. Now as far as oil capacity, look at the late model grand for the numbers. Drain the old oil out of the compressor into a measuring cup to see home much is in there(sometimes has oil in there other times not, refill with correct oil. Now fill capacity can be done with gauges if all else fails but should be done by someone who understands the numbers.

[82Eagle]

Thanks for the reply. Sanden calls for PAG 100 (SP-15) which of course won't mix with any residual mineral oil. I figured Ester oil, which will mix, would be fine in case I miss any. I can't remove all the mineral oil from a compressor as far as I know. Condenser is being replaced. Everything is being replaced except for the evaporator core and one hose.



I'll see how much oil, if any, comes out of the Sanden. I've read about a lot of folks using Ester oil in the 508's without issue, but I know it's not by Sanden's book.