How to Remove Excess Refrigerant Oil?
3 Answers
Adopt the method of repeatedly replacing the new refrigerant to reduce the oil content in the system. Weld open the exhaust pipe of the compressor and pour it out directly. If the refrigerant is excessive, simply release an appropriate amount.
Last time my car's A/C cooling performance deteriorated, the mechanic said there was too much refrigerant oil added. To remove the excess oil, the safest method is to go to a professional repair shop where they can use a dedicated recovery machine. They'll first vacuum and recover the refrigerant, then use equipment to separate out the excess oil, before finally performing a precise measured recharge. I once tried using a syringe to extract oil from the low-pressure line myself, but ended up introducing air into the system which caused unstable pressure, costing me more money to repair the lines. Now I understand - this isn't a job where you should try to save money by DIY. A deviation of just 20ml in oil quantity could cause the compressor to fail prematurely. It's much safer to leave it to professional equipment.
As an experienced DIY car enthusiast, I've encountered situations where the refrigeration oil was overfilled. A simple method is to run the AC for 5 minutes to circulate the compressor, then locate the Schrader valve at the low-pressure service port and slowly drain the mixed fluid into a transparent container using a dedicated oil extraction tube. After observing the separation of oil and refrigerant, you can estimate the amount drained. Important precautions: Always wear safety goggles to prevent splashes, and the ambient temperature should ideally be around 20°C. After draining, use an electronic scale to measure the refrigerant recharge amount - getting this step wrong means the entire system would need to be vacuumed again, which is particularly troublesome.
