Vamos air conditioner noise repair

Vamos air conditioner noise repair

  • 2005 model year: Honda Vamos
  • Model: HM1
  • Engine model: E07Z
  • Mileage: 150,000km

table of contents

  1. Abnormal noise from the underside of the passenger seat

Abnormal noise from the underside of the passenger seat

Inspection of air conditioner system

If you continue to drive with the air conditioner turned on, you will hear a continuous beeping sound from the box where the evaporator under the passenger seat in the room is stored. Moreover, the sound is sometimes linked to the accelerator pedal and is perfectly synchronized with the engine speed. When the air conditioner switch was turned off, the sound stopped, so I decided that it was related to air conditioner piping.

The high-pressure and low-pressure pipes of the evaporator and air conditioner, and the expansion valve are arranged under the passenger seat, which is the source of the abnormal noise. It was a continuous sound from some small part called “Gee”, so I thought that the air conditioner gas was leaking, but the air conditioner’s coldness itself is not so bad, and it has been some time since the noise started to be heard. However, the malfunction of the air conditioner does not appear as a symptom.

This car has a mileage of over 150,000 km, and the model year is 2005. It’s a fairly old car, but it seems that there is no history of repairing the air conditioner during that time. If there is a sound like some kind of gas leaking from this very narrow place called “Gee”, it is possible that the air conditioner has the function of releasing the refrigerant gas that has become high temperature and high pressure to the evaporator. It will be an expansion valve.

Review the basics of car air conditioners

However, the air conditioner itself is operating normally. When it comes to disassembling and servicing the expansion valve and the evaporator, repair costs are high and it takes a considerable amount of time. Moreover, the cause of the abnormal noise is not always the expansion valve …

Consider the cause of the abnormal noise in the first place. The reason why I predicted that the cause was the abnormal noise from the expansion valve was that the air conditioner compressor and the air conditioner oil in the piping became insufficient due to the mileage and age of the car, so the piping system This is because it was predicted that the air conditioner compressor inside and the parts were not properly lubricated. Of the parts that make up the piping system, the expansion valve plays the role of a fine valve. This valve may have caused noise by hindering the lubrication of the movement of the valve in the internal refrigerant passage due to lack of air conditioner oil. That’s what it means.

Based on the above troubleshooting, the entire air conditioner system was originally inspected and repaired, focusing on operations such as expansion valve replacement, evaporator cleaning or replacement, but due to various reasons (the air conditioner is working and the budget Due to circumstances), we decided to repair the abnormal noise by additionally injecting air conditioner oil and observing the situation.

Air conditioner oil replenishment

Air conditioner oil is exclusively for R134a.

The light blue round frame is the service valve. H is high pressure, L is low pressure。

Open the engine room and check the service valve on the low pressure side of the air conditioner piping. You can see the service valves for high-pressure piping and low-pressure piping on the upper left side from the rear hatch of the car toward the engine room.

Be sure to connect to the service valve on the low pressure side.

Use a simple air conditioner gas charger as shown in the photo. Of course, you can do it with a manifold gauge, but this time it’s only air conditioner oil, so you can work quickly with this. The procedure is as follows.

  1. The engine of the car is stopped.
  2. With the service can valve fully open, tighten the air conditioner oil can to install it. (Do not open the can at this time)
  3. Attach the coupler of the simple gas charger to the low pressure port of the air conditioner piping of the car.
  4. Loosen the air conditioner oil can body for about 1 second and tighten it again. At this time, the air is discharged quickly to bleed the air in the simple gas charger hose.
  5. Start the engine, turn on the air conditioner, maximize the temperature and air volume, and circulate the inside air.
  6. Tighten the service can valve of the simple gas charger, make a hole in the air conditioner oil can, and inject the air conditioner oil.
  7. After injecting everything, stop the engine with the simple charger as it is.
  8. Remove the simple gas charger.
  9. At 5, read the gauge pointer and replenish the air conditioner gas (R134a) as needed. (Be careful of overfilling)

Test run

For the time being, I conducted a test run while using the air conditioner as usual, but so far no abnormal noise has been generated. It seems that it has stopped exactly from the time of filling the air conditioner oil.

This completes the repair of the abnormal noise of the air conditioner, but when the pressure of the air conditioner gas was measured later with a manifold gauge, both high pressure and low pressure showed a value slightly higher than the appropriate value at a temperature of about 30 degrees. I can’t say anything because I don’t have a service manual, but I can still diagnose that the expansion valve is deteriorating. The coldness of the air conditioner itself is not always good compared to the condition of the new car, so it will be the first judgment factor in the diagnosis of air conditioner failure when a problem clearly occurs.

For the time being, please refer to this as an example of simple air conditioner repair.

Role and importance of air conditioner oil

Air conditioner oil is not only for lubrication of the compressor, which plays a role in compressing the low pressure refrigerant gas into the high pressure refrigerant gas and sending it to the condenser in the air conditioner system. It also has the role of sealing the entire pipe and preventing the leakage of refrigerant gas.

In addition, the high-temperature, high-pressure, gaseous refrigerant sent by the compressor is cooled by the condenser and condenser fan to change into a liquid, which is stored in the liquid tank, and the filter in it removes dust and impurities. It is removed and pumped to the expansion valve, but even at this time, the refrigerant is in a liquid state rather than a gas at high temperature and high pressure.

Air conditioning system basics

As in the previous repair case, the air conditioner oil is injected directly into the piping. That is, even when the refrigerant is pumped to the expansion valve, the refrigerant is in a liquid state and is mixed with air conditioner oil. Lubrication and sealing action by air conditioner oil is indispensable for the expansion valve to play a role of rapidly converting this high temperature, high pressure, and liquid refrigerant into a gas.

The shape of the expansion valve varies from car manufacturer to car manufacturer, but in any case, air conditioner oil plays an important role along with the compressor in this important process of air conditioner cooling.

As the car deteriorates over time, this air conditioner oil is also consumed, which reduces the amount of oil and makes it difficult to perform lubrication and sealing functions. Therefore, it is desirable to replace it regularly according to the manufacturer’s regulations.

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