Q: I have knocking in my engine. But then as I pick up speed it disappears. What could it be?

asked by on

I have knocking in my engine. But then as I pick up speed it disappears. What could it be?

My car has 118000 miles.
My car has an automatic transmission.

It sounds like you may have low oil pressure that may be causing some valve train noise as a result of the oil not properly reaching the top of the motor. This can happen for a number of reasons, but should be looked at very soon as it may eventually result in damaged engine components. As you pick up speed the engine rpms increase which cause more oil to be pumped to the top of the motor resulting in the noise going away due to the valve train components receiving more oil.

Generally, however when this happens the low oil pressure light will come on. The oil pressure light will usually come on when a few things could be happening. Either the motor is in fact low on oil, the oil pump could be failing or not pumping oil sufficiently or the oil pressure sending unit is not working properly and may be producing a faulty reading. If the engine is in fact low on oil, you may notice the temperature gauge reading above normal temperatures as a result of the lack of sufficient oil in the motor. I would recommend checking the actual oil level in the motor by using the dipstick. Be sure the oil level reaches the "full" mark. If this registers as "full" then you likely have a faulty oil pressure sending unit. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle to determine what may be causing your low oil pressure to cause this.

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. I have knocking in my engine. But then as I pick up speed it disappears. What could it be?

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: Squeaking metallic sound when turning

Thank you for the detailed information, it helps! The front driver side is where the majority of the steering components are located. Start by checking the power steering fluid. The best option is to raise the vehicle and inspect that...

Q: Q: I turn the key and nothing happens

Be sure any engine immobilizer system (security system) is not activated, thus preventing the car from starting. The battery should be load tested by a professional. Load testing can only be reliably performed on a fully charged battery. If the...

Q: P0174 bank 2 system too lean. If I keep driving with this code will I damage my engine? My car doesn't seem to be driving poorly

If your engine is running lean and you continue to drive on it with this condition, it can cause your engine to overheat and potentially damaged internal engine parts. Running rich is always better than running lean because extra fuel...

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...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...