how much ester oil in A/C system

gijams · 07-06-2012, 05:17 PM

I am starting up the A/C system in my 88 targa. The system has been open for 10 years. Amazingly it is holding vacuum. I am ready to charge the system (es12a) but do not know how to determine the condition and amount of oil in system. In one of the treads I have read, it was said that the oil would be dormant in the system and add new oil. The other option in to clean out all parts with A/c line cleaner. Because the system is holding vacuum I would prefer not to mess with in. Also, I live in Boston so the A/C is not used much.

Scott R · Scott R's Garage

This to me is nearly impossible to answer, the oil in the system is contaminated and should not be used or added to. Likewise if the system was open there are contaminates in the lines, the dryer, condensers and evaporator running it will likely damage the compressor over time.

You should remove all of the oil and flush the system, well then add oil to the compressor.

Jim Sims · 07-06-2012, 08:20 PM

IMO you will be taking too many short cuts and will likely be disappointed with the results. The system has to hold pressure (250 psi or higher on the high side) in addition to vacuum.

1982_928 · 1982_928's Garage

4oz or a little more in the system would be fine.. Change the dryer, but i have charged many open systems that had been open forever..

If you could find some r12 to put back in it, the AC would work much better..

kuehl · kuehl's Garage

In a PERFECT world you would replace the hoses with barrier hoses, replace the drier with one having XH-9 or other R134a compatible desiccant, add a low high pressure switch, replace the o-rings, AC liquid flush the 2 condensers, remove the compressor and insect it for signs of wear (bores, pistons, wobble plate), remove the evaporator and take of TEV and flush evaporator, put it all back together and add 5-6 oz of Ester.... all in a perfect world.

But, if you just want to 'try' to see what you can get with what you got, add 4-5 oz of ester oil, evac, charge and test. We have hundreds of clients whom have done just this and are satisfied for the moment. If things don't work out you will be re-visiting the Perfect world and then some.

gijams · 07-09-2012, 06:10 PM

Thanks for the help. I have decided to clean out the lines and components with in reason, check for leaks and charge the system. I will look into the dryer, ez12a is very moisture tolerant.

kuehl · kuehl's Garage

Quote:

Originally Posted by gijams

Thanks for the help. I have decided to clean out the lines and components with in reason, check for leaks and charge the system. I will look into the dryer, ez12a is very moisture tolerant.

Sounds like the start of a plan....
But, you might as well replace the o-rings, the drier, consider adding a low-high pressure switch to help protect the compressor. Since you have a post 85 car, inspect the evaporator. Buy lots of refrigerant if you don't plan on replacing the hoses with barrier hoses. And put some type of refrigerant identification sticker near the compressor. And... avoid sealants. And, check the underside of the engine deck lid above the compressor clutch, look for black line, if you have one consider the compressor nose seal.