Automotive Air Conditioning Information Forum

Hyundai tech can't tell you why a compressor has a clutch?

Variable displacement compressors do not cycle. They still need a clutch to turn on and off when the a/c is being used.

We can only help those that want to take the advice given. You have some responses from some very knowledgeable people when it comes to an auto a/c system. Might be wise to listen to them! They will and have helped many people and even saved them some money in the process.

Let's face it, very few shops can actually trouble shoot, so instead they sell you a whole new system, and a bunch of baloney to explain why that is needed

If you want real trouble shooting, ya gotta come to this forum

mrfezziwig wrote: ↑Tue Oct 05, 2021 5:04 pm OK. I took the car to the shop today. The refrigerant was very low and so they recharged the system. Unfortunately, this did not fix the problem. After more analysis the conclusion was that the compressor is bad. The technicians working on the car stated that the system did not reach the required working pressures. They backed this up by saying they could feel the 'sucking effect' on the compressor input side but could not feel a corresponding 'pumping action' on the output side. I believe this observation was made by grasping the metal piping leading to and from the compressor. There were no unusual noises from the system and there was no obvious leakage (dye was included in the recharge). As you can imagine, replacing the compressor and associated components is not cheap.

As mentioned, your compressor is an electronically controlled variable-displacement type. Before replacing the entire compressor at considerable expense, I would ask the shop to test the compressor's control valve using a scan tool or a test-set designed specifically for that purpose. Testing the control valve is done while monitoring the pressures on a Manifold Gauge Set. As the electrical parameters of the control valve change, so should the pressures. However, sometimes that doesn't happen, which would suggest a malfunctioning control valve.

If the shop doesn't have the scan tool or test-set to diagnose it, I would just replace the control valve outright. Tim has one in stock, as he pointed out, and it's relatively inexpensive compared to a brand-new compressor. Then, I would evacuate and recharge the system to specs as suggested earlier. The system might also have a slow leak someplace, but that could be addressed later.

Thanks everyone. Yes, finding a qualified shop has been difficult. I even contacted MACS to see if they could recommend somebody, but they had nothing in my zip. I will follow your recommendations and let you know I make out.