Common Causes Of High Suction Pressure

Common Causes Of High Suction Pressure

You are wondering what had happened to your car’s A/C system. It was working fine when you drove it yesterday. Now, you are only getting warm air from your A/C vents. In many cases, you do not need to send your car to the shop when you encounter minor A/C issues. You can troubleshoot those problems on your own! This post will provide some insights in dealing with high suction pressure:

Common Causes of High Suction Pressure

You may wish to check for:

  • Bad compressor reed valves
  • A/C system has been overcharged
  • Loose expansion valves
  • Expansion valve are stuck open
  • Head gasket on compressor is leaking

How to Fix High Suction Pressure Issues

  • If there are bad compressor reed valves: replace the bad reed valves.
  • If the system has been overcharged: remove some refrigerant.
  • If the expansion valve is loose: tighten the valve.
  • If the expansion valves are stuck open: replace the expansion valve.
  • If the head gasket on compressor is leaking: replace the head gasket.

Mastering Head Gasket Replacement Procedures

Head gaskets are designed to form a seal between the valve plate and cylinder head of your car’s A/C compressor. After many years of use, the inner portion of the gaskets will eventually wear out. When this happens, a leak within the pump of your A/C compressor can occur. This also means that the pumps can no longer build pressure properly. Before you begin the replacement process, you need to evacuate remaining air in the compressor. It is important to let all the excess air pressure out first.

Now, you are ready to take out the manifold cover. This gives you access to the connection points that need to be temporarily disconnected. You would need to do that to remove the pump from the housing. When handling your new gaskets, be sure to practice caution. You do not want to accidentally damage it before assembling it. When reassembling, you just need to line up the cylinder gasket on the valves, before the head gasket comes on. After that, you are ready to reassemble the remaining parts of your compressor.

What You Need to Know About Expansion Devices

As mentioned earlier, one of the solutions to fix high suction pressure problems is to replace the expansion valve. Some car owners may wonder what exactly it is. Expansion device is a generic term that can refer to an expansion block, expansion valve, or orifice tube. Orifice tubes need to be replaced and you do not have to clean them (they can never be cleaned!). You should deal with expansion valves and blocks by removing, inspecting, and replacing as and when required. An expansion device that has become stuck can allow excess amounts of pressure to build up in a system. This blows out the head of the compressor.

The rule of thumb is that if you are facilitating a compressor replacement procedure because it is not blowing cold enough or leaking, cleaning is acceptable. If you experience any other failure, you would need a new expansion device. If you are unsure, it never hurts to change out the entire expansion device.