qdeezie

Hello,

I will be doing a complete chemical flush of the a/c system on my truck and I bought ester oil to use as part of my retrofit. I'll be replacing the o-rings, accumulator, compressor and orifice as well.

I've done some further reading on this since purchasing the ester oil and I see a few arguments.

One says that Ford says that it's STRONGLY advised to use Pag 46 if a flush has been done and Ester is too heavy to properly circulate since the viscosity is 100.

Another argument says that Ester is truly universal and should be used when retrofitting because flushing will not remove 100% of the residual Mineral oil.

Does anyone have any experience or thoughts on this? I feel like Ester should be ok, but on the other hand if Ford is saying Pag 46 should be used after flushing, that's something to seriously consider.

Any thoughts? I'm trying to be one and done with my A/C if at all possible.

FYI - My vehicle is a 1990 F150 5.0L.

Thanks!

dr_bowtie

I dont flush it or replace the orings....I just vac it and fill it with the new stuff...works fine been doing it for years...only time I replace any orings is if I have to replace a worn part...other then that I wont open the system at all...

dirtcrew51m

hey doc, do you use a regular evac thing for the rfeon or a shop vac, not to sound like a smart *****, but I need to do my F150 and ranger and I wont spend the money for r12.

dr_bowtie

to do it right if there is freon in the system there is a set-up made by Robin-Aire that evacs the system and stores the Freon in a 20# propane tank so it isnt released into the air...

for a dead system I will use the air evac from Harbor Freight...you need an air compressor at least 3hp and the air with evac the system pulling it down to -28 vacuum then I add the new freon via the gauge set...I hook the vac to one side and the freon to the other...pretty nifty set up...

when I have a live system I need drained I take it down to a buddies who has the Robin-Aire evac and I pull all the freon out...the oil stays in the system either way.


thats the proper way to do it

tdcarter72

I done this last year, after getting some advice from some Ford shop guys, I used the Pag 46. They said to clean the system twice with the chemical flush and blow the system out with a air compressor after each flush. Just remember to save a cap full of the oil to lube the o-rings when installing them. I have not had any problems with my system so far.

Hope this helps!

qdeezie

In my instance, the A/C has no charge and I pulled the orifice out just to see what was going on with it and it was completely stopped up with all kinds of crud, so it needs to be flushed out.

qdeezie

Yes, it does. I'm feeling better about Pag 46 from your feedback. I'm going to go ahead and flush every part twice, then blow everything with compressed air and go the Pag 46 route. I still feel that there's a risk factor with Pag 46 because of that .001% of mineral oil seeped up in a corner somewhere, but it's a risk I'll have to take. I just don't want to destroy my compressor with a heavier viscosity oil if at all possible.

dirtcrew51m

Thanks doc.

Zacky

what is the "clean the system twice with the chemical flush" and what do you use for that?

mstrebe

I had to do a retrofit from an R12 to an R134 system on my truck. The compressor clutch had sheared in two pieces and the Freon was gone before I bought it, so there was no need to evacuate it.

I hooked up a new compressor, evaporator/dryer, and fittings with the green O-rings. Used ester oil rather than PAG in case there was still mineral oil in the system. That was back last September and it’s running nice and cold now in the Texas heat.

if you’re worried about residual R12 I wouldn’t worry about using ester oil in place of PAG, I have had no issues since I did the work.