Guidance on AC repair path

[Terry Kay]

<<my setup was R12, Sanden 709 compressor re-used. It was converted to 134a, and then Ester 100 synthetic (R12 and 134a compatible) was added. Therefore there was mineral in there originally, then converted to 134a with ester100 synthetic added 8 years ago. Aside from the 134a leaking out over 8 years, no issues. The bottle I used looked very similar to the Ester100 synthetic included in the R134a conversion kit sold by Van-cafe.>>

There's always room for Jello.

You've got quite the quagmire of lubricants in your lines there Dennis--
Should have stuck with R-12 & the mineral oil from the get go.
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T.K.

[denwood]

Ester 100 synthetic is 100% compatible with R12, 134a. I'm assuming this is why Redtek has standardized on this oil for their oil charge.

In my case, there must have been mineral oil in there 8 years back. The AC shop gave me the Ester100 to add to the system as I reinstalled the engine. Knowing they were getting the van as a final step to sort the AC, I did what they asked.

8 years forward to last week...the system was very clean on flush. All I got out is solvated oil (dye was in there). All that's been added is Ester100 synthetic. Therefore, that's all I'm adding now to avoid mixing types.

Cheers,
Dennis
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Cheers,
Dennis Wood
The Grape

[mbwesty]

[denwood]

Mixing the oils won't hurt at all (based on research only). The bigger concern is r12's reaction to PAG. If you're using neither..nothing to worry about. One thing I have learned is that both PAG and Ester are synthetic. Sanden recommends PAG for their compressors only. Mineral or ester voids the warranty on new compressors. That said, I see ester referred to as the universal oi as it is fine with everything...which is why you would use it in a retrofit. Can get confusing for sure.
_________________
Cheers,
Dennis Wood
The Grape

[mbwesty]

So just to report back after weeks of delays I have the A/C blowing at about 58 deg. I put in 3 cans of redtek and 1 can of stop leaks and I was only able to get the high side to 175psig. I am ordering couple more cans of redtek to finish the job...

Dennis, so I ended up using ester oil as I had replaced the compressor. The drain bolt had stripped the compressor housing as I was torquing it. I guess that was a sign. I ordered the new compressor (~$270) from Southeast Air and the main delay was from them as they had entered the wrong zip code in the ship to address. It took 2 weeks for me to get the new compressor. I did have to reuse the old compressor head as the new one had on the wrong ports (that I knew at the time of ordering).

I think the biggest confusion for me before any hands-on and from reading the forum was how the oil flow and if the oil is separated between the compressor "crankcase" and its head. Since I had the system cleaned to "bone dry" so I just put in 8oz of ester in the compressor then bolt it up and let the oil circulates. Thanks for all the inputs and it made things easier.

Now, one last question...anyone knows how to unscrew the high side connection without having oil and R-12a sprayed everywhere?

[denwood]

You may actually be exactly where you need. 3 cans is the official redtek requirement for the van.

I ended up overcharging which is a PITA to deal with as you bleed off and try to monitor temps.

Outside temps at your condenser up front as well as your fan speed on the evap have a major impact on pressures that you will see..and I've charged the system more than I'd like to admit now. Also, where you check the vent temps is clearly an issue. 58 at the plenum exit likely measures out at 48 right at the fan exit, particularly if the van is warm.

Another thing to consider is that likely you've got the van running with the engine lid off and a warm engine. In my garage, that created 100 degree intake air to the evaporator! I'd leave your charge where it is, and take a test drive or two to see what you get at rpm

Cheers,
Dennis.
_________________
Cheers,
Dennis Wood
The Grape

[mbwesty]

hey, just to report back...I finally got to finish charging the A/C. It's about 50 degree at the plenum with the IR. The 58 degree before was at the blower exit and the plenum was not installed. I charged the A/C at 1500rpm, and for some reason I did not have a steady 200psi on the high side. It was more like 150psi. So from talking to Doug Simpson at Redtek he said I should charge the high side to 38psi so I had just charged it to that. Well, after overcharging and bleeding it back down. I did learn that overcharging would bring up the A/C temp...

Santa Ana wind and A/C is nice...until next project...probably a tencent engine upgrade...Tim