Clatter/knock when cold

[Werlyb23]

Anybody else roll the windows down and hear pretty loud clatter when accelerating cold? I have heard a bunch of people mention this in other forums, just curious what people thought. It threw me off this morning when I heard it-had me like

 

[Jstawgn]

This is nornal behavior of direct injection engine. Unfortunately just the nature of the beast. But it gives a lot of other benefits too. Can run much higher compression with turbo and much lower risk of detonation.

 

[Werlyb23]

This is nornal behavior of direct injection engine. Unfortunately just the nature of the beast. But it gives a lot of other benefits too. Can run much higher compression with turbo and much lower risk of detonation.

Ok thanks for the reply! Why does it only do it while cold? Once it warms up after a couple minutes it disappears

 

[Cablebandit]

Is it related to oil pressure?

I know one of my motorcycle's sounds like two skeletons ****ing in a metal trashcan until the oil pressure adjusts the cam chain.

 

[Werlyb23]

Is it related to oil pressure?

I know one of my motorcycle's sounds like two skeletons ****ing in a metal trashcan until the oil pressure adjusts the cam chain.

ahhh could be.....which would explain why it's only for the first couple minutes of the drive

 

[Jstawgn]

Ok thanks for the reply! Why does it only do it while cold? Once it warms up after a couple minutes it disappears

Gasoline viscosity are like oil. It does thin out a lot at higher temperature. Direct injection is running at 2000-3000 PSI compared to 60-80 PSI for Port injection. When cold it runs higher toward 3000 PSI pressure as the higher viscosity is giving much higher resistance. This unfortunately also increase noise.

There is a story in landcruiser forum of someone that treaten lemon law because of this noise. Dealer tear down the engine and cannot find anything wrong. All the other new LC also makes similar noise. I noticed this noise in a few youtube videos. This definitely would be a shock to anyone used to old GX and LC. It's just different. Does not means there is something wrong with it.

 

[kalieaire]

My sister's 2012 Prius C sounded the same way, just clattering the entire time. Fortunately, it seems to go away after 5-10 minutes of driving and to the point the oil temps are normal.