Radiator and Cooling System – Page 4

If your aircon is making loud noises, it is usually because its belt, pulley, or tensioner are faulty. However, the compressor failing will make a loud noise too. Here we'll examine in more detail the different loud sounds your air-con may make and the fixes and cost of repair for each one. In total, there are seven loud aircon noises: BuzzingSquealing or ScreechingGrindingRattlingHissing or WhistlingSlapping, Clicking, KnockingVibrating Hum 1. AC Loud Buzzing Noise You're more likely to hear this noise if you've just had your aircon gas topped up or a complete AC service. Occasionally a car shop will mistakenly put too much Freon (the gas used in car aircon) into the compressor. Aircon recharge What you're hearing is the compressor struggling to move the gas around to the condenser. It has entered the compressor port and is causing the compressor to vibrate as there is too much pressure in the system. When the compressor reaches a certain threshold, the AC generally turns off completely to prevent further damage. This results in hot air entering the cabin. If you hear this noise take it back to the mechanic, and he'll safely remove some. This isn't a job you can do yourself, as the refrigerant gas is poisonous and needs to be disposed of safely. If you haven't had a regen recently, the loud buzzing noise may be the compressor starting to fail. Compressors can sometimes be refurbished if you notice the fault quickly enough. If you leave it too long and it fails completely, you'll be looking at an expensive bill. The cost of replacing a car's AC compressor ranges from $500 - $1,250, depending on the make and model of the car. Labor costs are $150 to $225. The air compressor part costs between $250 and $950. 2. AC Makes Loud Squealing or Screeching Noise The serpentine belt runs Air Con and Power Steering, amongst other components. They can make a screeching or squealing sound when they slip or become brittle. Generally, these belts are good for 50,000 miles, but if the aircon is in constant use, they can fail before then. So the sound is more common in older cars. Brittle Serpentine Belt This noise can be so loud you can hear it within the cabin. Lift the hood and press on the air con for ten seconds. Listen out for the sound. You'll notice it louder by two belts coming off the engine and traveling down to another large engine part. This part is your aircon compressor. Turn off the AC and see if the sound stops. If so, it's very likely to be the AC belt that needs replacing or tightening. You'll have problems getting cold air into the cabin if the compressor doesn't get enough power to pressurize the coolant before it's sent to the condenser. The compressor pulley can also make a squealing noise when the bearings start to fail. Luckily this is a cheap fix. A replacement AC belt costs between $15 and $38. Labor costs are between $50 and $100. The total cost depending on the car model and the brand of the belt is between $$65 and $138. 3. AC Makes A Loud Grinding Noise You'll hear a loud grinding sound if The bearings on the air con pulley are bad. This often happens when a seal becomes loose, and the grease leaks away, causing a metal-on-metal grinding noise. This is a cheap fix. or, The aircon compressor itself is failing. It's a sign the pistons within it are not pumping smoothly, and the internal parts are misaligned. An expensive fix. It could mean you'll need a brand-new compressor. https://youtu.be/SUheJNhrLVo?t=73 Testing belts and AC compressor for grinding noise faults It's best to turn the aircon off and get your car to a mechanic right away, as the earlier you get it checked, the more chance there is of refurbing the compressor than replacing it. 4. AC Makes a Loud Rattling Noise Here are the four parts that may be loose and cause the rattling noise you're hearing. The belt tensioner. As the word implies, the belt tensioner's job is to keep the belt tight on the pulleys. This ensures it runs smoothly. It works fine when doing its job, but if it becomes loose, the belt will become loose, too, and rattle around as it spins on the compressor. The Serpentine belt Under heavy load (when the AC is on) can make a loud rattling noise. It might still rattle with the air con off, but it increases in volume when switched on. Belt pulleys The pulleys guide the belts. Often when the air con is on, other belts also are put under more strain. The power steering pulley - for example- may show added signs of stress when the aircon is on. Although this seems vague, it's because the noise really could be caused by any belt, pulley, or tensioner. The good news is a decent mechanic will quickly identify the issue and fix it cheaply. Air Compressor rattling If the AC compressor makes a loud rattling sound, it could be expensive if the part can't be refurbished. The compressor clutch is a part that is prone to failure. If you hear a rattling noise inside the compressor, it's a sign of bad clutch bearings. In humid conditions where drivers use the aircon all year round, they are prone to failure due to the amount of stress they are put under. The cost of replacing the AC compressor clutch is between $50 - $75 for the part and $150 - $250 for labor. This depends on the make and model of the car. 5. AC Makes a Loud Whistling or Hissing Noise A hissing noise when you turn your air con off is normal. A loud hiss isn't, though! There is supposed to be a pressure difference when running as that's what forces air con through your car vents and into the cabin. A loud hissing noise indicates a leak in the circuit and, over time, will cause the gas to leak out of the system altogether. When turned off, the pressure within your car's aircon system must equalize the pressure of the gas refrigerant. This fix could be as simple as a leak in the refrigerant lines between the compressor and the condenser or an issue with the compressor itself. Luckily, leaky lines are more likely. If this is loud, you will quickly locate the bad line by lifting the hood and listening with the engine off. If you can't find the leak, a mechanic will pressurize the system to find it for you. The cost of replacing the refrigerant lines is approximately $100 - $250, including diagnosis and fitting. 6. AC Makes a Loud Slapping, Clicking, or Knocking Sound This noise is likely caused by a loose part moving around slightly under the hood. No noise is good noise, but at least with a loud kick, slap, or knocking noise, it's usually a cheaper fix. This isn't usually a noise you'll hear inside the cabin but one you might notice if you have the aircon on and the hood up. The aircon compressor is held in place by mounting bolts. After many thousands of miles, these can start to corrode and work loose. Inspect the compressor to look for signs of this. Another reason for this noise is that the belt connecting the engine crankshaft to the compressor is loose, frayed, or slipping. 7. AC Loud Vibration Type of Sound The more strain a loose serpentine belt is forced to work under, the more vibration noise occurs. This noise is likely accompanied by other sounds, particularly a rattle - if the belt pulleys have failed- sound. In Conclusion There are two main reasons your aircon may be making various loud noises. The causes fall into two main categories: belt—related and air-con system issues. Almost always, belt issues will be the reasons for the noises you're hearing, and this is good news as they are by far the cheaper fixes. Always investigate belts, tensioners, and pulleys first before moving on to more potentially expensive issues. 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