Q: Engine knock and bad sounds on start

asked by on

Whenever I start up my 2007 Toyota Tundra in the cold there is a kind of knocking in the engine. The first time I heard this I had it checked out and the mechanic said it was “piston slap." Not sure how worried I should be about this problem, engine is running fine 99% of the time. This truck has 70,000 miles on it, is it time to be worried?

Since you describe your issue happening when you first start it cold, I’m assuming the noise goes away shortly after starting. When your engine is running, the internal components are literally floating on oil that is constantly pumped and supplied to them and fill micro spaces. When your engine has been sitting for a while and gets cold, it is enough time for the oil to drain down and out of the passages. When you first start your engine after this, there is a brief time where the micro spaces have no oil pressure, only residual oil. If a part is worn enough it can exhibit a knocking or tapping sound until the oil pressure overcomes it, once again filling the gaps. If the knocking sound you’re experiencing goes away after starting, I would recommend a compatible oil additive. This may improve the situation. It is noteworthy however, that Toyota considers the knocking sound to be “normal”.

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. Engine knock and bad sounds on start

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: Whilst driving the car will cut out. In the begining it would start immediatetly now if it cuts out it doesnt want to start

Hello. I would need to know the model of your Toyota to be able to give you the best information. From what you are telling me though it sounds like the crank sensor harness may be damaged or that one...

Q: Whining noise, fuel system issue

Hello. You should stop driving the car until this is addressed. You didn't specify where fuel was squirting out, but in any case, this is a serious safety hazard. Given the age of your vehicle, and that it as been...

Q: I changed my mas and the check engine light came back on what next

You will need to have the computer scanned to see why the light came back on. If you continue to get codes to the mass air sensor then you should have the pinpoint test completed that will test the system...

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...
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...