Car’s Air Conditioning Orifice Tube: Symptoms and Replacement

Spare Parts for Ashok - Car's Air Conditioning Orifice Tube: Symptoms and Replacement

The spare parts industry pundits of one of the leading suppliers of Spare Parts for Ashok Leyland in this blog would like to discuss in detail the symptoms and accordingly the replacement procedure of car air conditioning orifice tube, or most commonly known as the expansion valve. Orifice Tube is a device that plays a quintessential role in the high mileage automobiles. We know why air conditioning systems are put in cars, obviously to keep the passenger compartment of a car cool and airy. Among many other parts that keep the car AC system running, Orifice Tube is the one that is critical to the optimum functioning of the car air conditioners.

Before the auto part experts of the highly acknowledged and world-renowned dealers of Leyland Truck Parts get straight down to why orifice tubes malfunction and signs they roll out when they rear the impending failure, let first understand the reason why they are a part of a car’s air conditioning system.

Why is Orifice Tube there in your car’s AC system?

The orifice tube, most popularly known as expansion valve is there in your car’s AC system to keep it flowing. You’ll find the orifice tube in the car’s AC system at the evaporator inlet. They gauge and monitor the flow of refrigerant entering the evaporator. The brass hole of a predetermined size tracks this refrigerant. Since the car air conditioning system’s operation needs vary depending upon the need of the passengers sitting in the car cabin, sometimes high and sometimes low, the orifice tube controls and accordingly adjust the amount of refrigerant going into the evaporator. This balancing of the flow of cooling inside the cabin is necessary for the AC to operate effectively.

Read AlsoLet’s Talk About Compression Ratio

Irrespective of the car air conditioning system’s operating condition, if too much refrigerant is allowed to enter the evaporator, it would get too cold inside the passenger cabin, and ultimately the moisture collected on it would freeze on the evaporator coil. This extreme freezing on the evaporator coil would discourage the flow of hot air through the fins, dismissing the cold refrigerant flowing inside the evaporator coil to absorb heat from the air. This will eventually lead to a complete cooling halt. Similar is the case, if we were to allow too little refrigerant to enter the evaporator, then there would not be enough refrigerant to absorb the heat from the air, thus zero cooling effect.

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Now, this continuous metering of the flow of refrigerant entering the evaporator according to evaporator temperature and the load and cooling demand of the AC system may lead to certain problem or failure of the expansion valve or orifice tube.

Let’s have a look at some of the tell-tale signs of a faulty expansion valve or orifice tube.

Air conditioning system blowing hot air: This puts a stamp on the fact that something is definitely not ok with your AC system’s metering device. The AC system’s expansion valve work hand-in-hand with the system’s orifice tube to regulate the flow of refrigerant entering the evaporator. So if either of the components malfunctions or witnesses an issue, it can put a huge burden on the working and performance of the AC system. This can cause the air conditioning system to underperform. The AC system might start giving less cold air than before or worse, it may start giving hot air.

Frost on the evaporator or coming from the air ducts: Another issue with the malfunctioned or failing AC expansion valve or orifice tube is the frost coming from the air ducts or the AC vents. When the AC expansion valve or orifice tube fails, it can cause an unregulated and unmetered amount of refrigerant to flow through the vehicle’s AC system. This causes the freezing of the evaporator coil or frost coming from the vehicle’s AC vents because of the escalated supply of the refrigerant through the vehicle’s AC system.

Round the clock running AC compressor: Failed expansion valve or orifice tube can also lead to AC compressor running constantly, that is the compressor will pump refrigerant continuously through the vehicle AC’s system, even when there is no need for the compressor to do so. This will put the compressor and other AC system’s components under uncalled for pressure leading to premature failure of the system entirely.

The expansion valve and the orifice tube are important vehicle AC system components critical to the working and performance of the AC system. If you have a suspicion that your vehicle’s AC system might be having a trouble, have your vehicle’s AC system inspected by a professional mechanic or do the replacement yourself.

Steps to Replace Your Vehicle’s AC System Orifice Tube

Tools Required

  • New Orifice Tube
  • Seal
  • Screwdriver
  • Nose Pliers
  • Wrench Set
  • Drain Pan
  • Drop Light
  • Safety Glasses
  • Coveralls and Gloves
  • Vehicle Owner Manual

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Step 1: Before getting straight under the hood of the car and looking for expansion valve and orifice tube, get familiar with the entire AC system by referring to the vehicle owner manual. This will help you get used to with all the AC system components and the parts you have to work on and replace.

Step 2: Now, locate the orifice tube which you will find housed in a Y junction, sandwiched between the condenser and the front evaporator. It runs along the side of the radiator, close to the mounting.

Step 3: Taking an open-ended wrench, disconnect the orifice tube by loosening up the coupling in the liquid line, just after the junction box, away from the radiator. You will find a small rubber seal within the liquid line that must first be removed in order to remove the orifice tube. Use a screwdriver or nose pliers to remove the seal, located on the end of the liquid line coupling.

Step 4: Now, you’ll clearly see orifice tube within the liquid line. Using pliers take out the orifice tube out of the line. Do it carefully, to avoid doing harm to both liquid line and orifice tube.

Step 5: Once the faulty orifice tube is pried out of the line, put the new one back on. Simply follow the steps in the reverse order we have just mentioned to put everything back together.

Step 6: Once everything is back in their original place, charge the air conditioning system. Once charged, switch on the air conditioning system and if it is allowing better flow of air.

For more information on this topic, please visit BP Auto Spares India or ask the experts.