Q: My car developed a very loud knocking sound.

asked by on

I have car that developed a loud knocking sound. I don't really know what it is, I was told it could be a rod or the rocker arm but I don't know how to get to them. Can I get to it without taking apart to much of the car?

My car has 175000 miles.
My car has an automatic transmission.

It is possible the valve lifters are starved of oil due to a failure in the rocker arm. There are reported cases where the rocker dowel pins shear off. A direct consequence of that is oil starvation as the oil holes get covered. The rocker arms are part of the cylinder head assembly, so it is an on the vehicle repair and YourMechanic specialists, depending on your region, will be able to complete the work. Just to make sure that it is an internal engine noise, you can disconnect (briefly) the serpentine belt that drives all of the accessories and see if, by chance, the noise goes away (just in case it’s a failing alternator pulley bearing for example). It sure sounds like a valve lifter oil starvation issue though.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. My car developed a very loud knocking sound.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I'm getting an "Oil Pump Pressure Is Low" warning light on my dash, followed by loud tapping sounds from the engine.

The oil pressure sensor only "reads" and reports pressure. The sensor itself cannot "affect" or "set" pump pressure. If the oil pressure warning light illuminates AND there is coincident unusual engine noise, that almost undoubtedly means that oil pressure really...

Q: My temperature gauge reads cold - 2004 Chrysler Sebring

Hello there. A few common faults will cause your 2004 Chrysler Sebring to to stay at C on the temperature gauge. The most common are a faulty coolant temperature sensor, failing temperature gauge, or wiring harness fault. If the engine...

Q: Q: Blown engine

In the 2007 model year the Ford Fusion was available with a 3.0L 6 cylinder motor or a 2.0L 4 cylinder motor. In 2011, the Fusion was available with those same options as well as the 3.5L 6 cylinder dual...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...