Skip the auto shop - Our mechanics make house calls

Q: Car makes knocking sound

asked by on

My car runs but makes a horrible knocking sound like the piston wants to come through the block. I was told that I blew a valve or had a valve-related issue. And when it runs too long, it overheats but maintains oil levels.

A valve train issue usually sounds more like a tapping sound similar to a pencil tapping quickly on a desk. Depending on the engine, a vehicle with a 4 cylinder engine can have as many as 16 valves. If several of those have problems, it sounds like a bunch of pencils hitting the desk. When it is something in the "bottom end" of an engine, meaning piston, crankshaft, rod or mains, the knock is like a carpenter hitting the side of the engine with a hammer. This sounds more like what you are describing. A lower engine knock is very serious. It requires at the minimum opening up the engine to replace bearings if no other damage has been done. Depending on mileage, it might be best to rebuild the engine altogether. Seek help from a qualified mechanic that can go and inspect the vehicle’s knocking sound, such as one from YourMechanic. They will be able to better determine what direction you should go.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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 was replacing the water pump and one of the bolts broke. Can a mechanic assist in drilling it out?

Hi there. Depending on where the stripped bolt is on the pump, you may be able to have this bolt hole re-tapped with a Heli coil, essentially recreating new threads in the pump for the bolt. In the event that...

Q: Car starts fine, but won't shift into Drive

Hello. The only transmission fluid related cause that would account for your symptom is low fluid level. Be wary though of adding too much fluid which can cause other problems as the fluid becomes entrained with air. If the fluid...

Q: knocking sound

You would first need to determine if the engine noise is a lower engine noise or an upper engine noise, as this would make a big difference on the repairs that would be needed for your 2000 Chrysler Town &...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...