AC System Low on Oil

[dlundblad]

Can't seem to find an answer anywhere.

My AC evaporator is leaking oil. I remember reading somewhere (perhaps here?) that if the system is low on oil, it is smart enough not to turn the compressor on. How true is this? If it doesn't, I imagine running the AC (defrosters) while it's low on oil would be bad..

Thanks in advance guys.

 

[another Todd]

If the evap. is leaking oil, it is likely the gas has leaked out too, and that would cause the compressor to not engage. The leak must be stopped (replace evap.), and system recharged before the system will operate normally. If you are talking about a slight weeping around a fitting I wouldn't worry about it.

 

[bluestream]

Has it been dripping out on the floor? Or a little damp in one spot?

 

[dlundblad]

It made a 50 cent piece sized spot on the ground.

 

[mk378]

There is no oil detection. There is a pressure cutoff when the refrigerant all leaks out, which is eventually going to be the case here. You should unplug the compressor to be sure it doesn't run until repairs are made.

 

[dlundblad]

Awesome.

I'll just pull the AC relay.

 

[Chris142]

The compressor has pistons,crankshaft etc just like an engine. It needs oil or it will burn up.

 

[kschachn]

Just to echo the others... The focus on oil is somewhat misguided. If it is leaking oil then it is leaking refrigerant, and once that gets low enough the low-pressure cutout switch will prevent the compressor from engaging. There's really no way to measure the amount of oil in the closed system, it is distributed within the various components and the piping. Once you replace the leaking evaporator there is a designated amount of oil you are to add to the component to replace what is lost by removing it, but that doesn't account for what might have leaked out. That's going to be a guess.

And you say your evaporator is leaking and you see an oil spot on the ground, where is it dripping from? If an evaporator is leaking oil there's really only one place it can leak to the outside, and generally they don't leak enough oil to drip from there. Usually the oil from an evaporator leak is absorbed into any dirt or debris caught in the evaporator fins, or into the foam insulation around the core. I've never seen one with a leak that actually drips oil to the outside.

 

[nthach]

What car? Some compressors like Sandens will keep a tiny bit of oil in them, while most (Denso/Delphi/Visteon) don't keep oil - the refrigerant moves oil throughout the system, the cutoff switch is only to protect the system during a high pressure event and to keep the compressor from kicking when the system pressure(not charge) is low.

There are also two types of compressors - piston type or scroll type. The former has more moving parts.

 

[dlundblad]

I pulled the AC clutch relay a few days ago and I assumed all was well. I must have bumped the AC button today and sure enough the thing was running. (I was able to hear it disengage, then engage and disengage again.) Anyone have any idea why it was still on? I went ahead and pulled the AC clutch fuse as well.

http://www.wjjeeps.com/misc/power_dist_ctr_02.jpg
#36 is what I removed originally. I went ahead and pulled #21 too.

 

[dlundblad]

Originally Posted By: kschachn
Just to echo the others... The focus on oil is somewhat misguided. If it is leaking oil then it is leaking refrigerant, and once that gets low enough the low-pressure cutout switch will prevent the compressor from engaging. There's really no way to measure the amount of oil in the closed system, it is distributed within the various components and the piping. Once you replace the leaking evaporator there is a designated amount of oil you are to add to the component to replace what is lost by removing it, but that doesn't account for what might have leaked out. That's going to be a guess.

And you say your evaporator is leaking and you see an oil spot on the ground, where is it dripping from? If an evaporator is leaking oil there's really only one place it can leak to the outside, and generally they don't leak enough oil to drip from there. Usually the oil from an evaporator leak is absorbed into any dirt or debris caught in the evaporator fins, or into the foam insulation around the core. I've never seen one with a leak that actually drips oil to the outside.


Apologizes I am just now seeing this. My terminology was wrong. It is the condenser that is leaking.

I ended up ordering a Denso condenser Monday too so I am not sure what I was thinking.