Want to drain all AC oil and start over.
06-21-2017, 01:19 PM
#1
Want to drain all AC oil and start over.
I'm planning to reclaim the system and want to get all the old oil out and start over with the proper charge and oil.
Can I blow it out with nitrogen and flush like a typical split system?
How deep of a vacuum do you pull? I typically pull down to 500 microns.
Thank you in advance. I'm an AC guy and have great gauges and connectors. Never done a car / truck.
Tim
Can I blow it out with nitrogen and flush like a typical split system?
How deep of a vacuum do you pull? I typically pull down to 500 microns.
Thank you in advance. I'm an AC guy and have great gauges and connectors. Never done a car / truck.
Tim
06-21-2017, 02:33 PM
#2
Senior Member
I'm not sure if you'll be able to get all your oil out without removing the compressor and dryer and flushing the rest out with solvent. With that said, I'm not sure why you'd want to remove all the oil unless you had a really bad failure.
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TimcoF150 (06-21-2017)
06-21-2017, 03:55 PM
#3
Typically an automotive ac system will hold approx. 2oz oil per component, evap, rec/drier-accumulator, condenser, and the compressor will hold about 4-6oz, the only way to get it all out is to physically remove every component and up end them to drain.
There is no reason I can think of where doing something of this nature except for catastrophic compressor failure, been fixing auto a/c for over 25 years and have never seen the need.
What is recommended is to flush the lines, condenser, evaporator, and depending on the type of system replace the accumulator/receiver drier, and compressor as it will have failed.
Once the system is flushed the compressor will come with instructions for amount of oil to add back into it then calculate 2oz more for every other component replaced.
Install inline filters, both low and high side into the lines, typically the high side filter will be a pancake style and either thread inline between coupling or a quick coupler, the low side that I am familiar with require splicing into a rubber hose.
Vacuum the system down to as close to 30" Hg as you can get and leave it for at least 30 mins then recharge the system.
Once completely charged you will run the engine with a/c at high idle, around 2000 rpm's for 30 mins, discharge the system and remove the high side filter, leaving the low side filter in place, vacuum and recharge again and done.
If no failure of compressor ignore everything above aside from the 2oz per component and 4-6 oz for a new compressor.
.
There is no reason I can think of where doing something of this nature except for catastrophic compressor failure, been fixing auto a/c for over 25 years and have never seen the need.
What is recommended is to flush the lines, condenser, evaporator, and depending on the type of system replace the accumulator/receiver drier, and compressor as it will have failed.
Once the system is flushed the compressor will come with instructions for amount of oil to add back into it then calculate 2oz more for every other component replaced.
Install inline filters, both low and high side into the lines, typically the high side filter will be a pancake style and either thread inline between coupling or a quick coupler, the low side that I am familiar with require splicing into a rubber hose.
Vacuum the system down to as close to 30" Hg as you can get and leave it for at least 30 mins then recharge the system.
Once completely charged you will run the engine with a/c at high idle, around 2000 rpm's for 30 mins, discharge the system and remove the high side filter, leaving the low side filter in place, vacuum and recharge again and done.
If no failure of compressor ignore everything above aside from the 2oz per component and 4-6 oz for a new compressor.
.
Last edited by RLXXI; 06-21-2017 at 04:01 PM.
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TimcoF150 (06-21-2017)
06-21-2017, 10:05 PM
#4
The engine was pulled before I bought it. AC has always come in waves. I want to evacuate and pull a vac and recharge. If I pull all the old charge, how do I determine the oil level and how much to add with the new charge?
06-21-2017, 10:08 PM
#5
Typically an automotive ac system will hold approx. 2oz oil per component, evap, rec/drier-accumulator, condenser, and the compressor will hold about 4-6oz, the only way to get it all out is to physically remove every component and up end them to drain.
There is no reason I can think of where doing something of this nature except for catastrophic compressor failure, been fixing auto a/c for over 25 years and have never seen the need.
What is recommended is to flush the lines, condenser, evaporator, and depending on the type of system replace the accumulator/receiver drier, and compressor as it will have failed.
Once the system is flushed the compressor will come with instructions for amount of oil to add back into it then calculate 2oz more for every other component replaced.
Install inline filters, both low and high side into the lines, typically the high side filter will be a pancake style and either thread inline between coupling or a quick coupler, the low side that I am familiar with require splicing into a rubber hose.
Vacuum the system down to as close to 30" Hg as you can get and leave it for at least 30 mins then recharge the system.
Once completely charged you will run the engine with a/c at high idle, around 2000 rpm's for 30 mins, discharge the system and remove the high side filter, leaving the low side filter in place, vacuum and recharge again and done.
If no failure of compressor ignore everything above aside from the 2oz per component and 4-6 oz for a new compressor.
.
There is no reason I can think of where doing something of this nature except for catastrophic compressor failure, been fixing auto a/c for over 25 years and have never seen the need.
What is recommended is to flush the lines, condenser, evaporator, and depending on the type of system replace the accumulator/receiver drier, and compressor as it will have failed.
Once the system is flushed the compressor will come with instructions for amount of oil to add back into it then calculate 2oz more for every other component replaced.
Install inline filters, both low and high side into the lines, typically the high side filter will be a pancake style and either thread inline between coupling or a quick coupler, the low side that I am familiar with require splicing into a rubber hose.
Vacuum the system down to as close to 30" Hg as you can get and leave it for at least 30 mins then recharge the system.
Once completely charged you will run the engine with a/c at high idle, around 2000 rpm's for 30 mins, discharge the system and remove the high side filter, leaving the low side filter in place, vacuum and recharge again and done.
If no failure of compressor ignore everything above aside from the 2oz per component and 4-6 oz for a new compressor.
.
06-22-2017, 05:14 AM
#6
.
06-22-2017, 08:07 AM
#7
Senior Member
I'm in the boat that its probably not necessary, but if you want to go through with it, there are a ton of AC solvents on the market to remove the oil. We do it as standard preventative maintenance on our industrial units at work. I'm not sure how this would be done with an automotive unit, since I've only seen specialized equipment specifically for use with solvent for our large industrial units. I imagine the hard part would be finding a way to circulate the solvent through the system.
Like was said before, make sure you replace the filters/driers. Pretty standard procedure if you're familiar working with HVAC.
Like was said before, make sure you replace the filters/driers. Pretty standard procedure if you're familiar working with HVAC.