Why is my car making a knocking noise underneath?

A bad serpentine belt could be a culprit of knocking noises. A normally functioning belt turns smoothly when the engine runs. When the belt stretches or goes bad, you’ll hear a rattling noise as you’re driving. To fix this issue, take it to a mechanic.

Why are pipes knocking?

In most cases, knocking pipes are caused by variable water pressure in the main supply pipes coming into your home. However, when the air used in pressurizing those pipes leaks or is depleted, water moves suddenly and violently, creating the knocking sound as it traverses the length of the supply lines.

How do I get rid of the knocking noise in my engine?

How to Fix Engine Knocking

The first step in trying to fix engine knocking is to upgrade to gasoline with a higher octane rating.
Give your engine a tune-up that includes new spark plugs and wires.
Regularly change the oil in your vehicle and monitor for a low oil level.

When I slow down I hear a knocking sound?

Check the brake system and see if the caliper or rotor is damaged on the driver side wheel. Since the noise only occurs when decelerating to a stop, then there could be an issue with the brakes. If the noise is still there, then either there is a loose suspension part or there is a problem with the transmission.

How do I stop my water pipes from banging?

How to stop water hammer

Is air pockets the problem? Another issue that can cause a similar banging sound is actually air pockets in your pipes.
Close valves half-way.
Replace intake connections.
Install water hammer arresters.
Secure the pipe.
Install pressure limiting valve.
Install different taps.
Call the plumber.

Can a pulley make a knocking noise?

When the tensioner or tensioner pulley fails, the loss of tension can cause the belt and pulleys to make high-pitched rattling or chirping noises. If the pulley bearing completely fails, it can also cause a squealing or even a grinding noise. Symptom 2: Knocking or slapping. This can cause a slapping or knocking noise.