Is cold start knock a common occurrence on the RX350? We have a 2008 model that we bought used in May 2010 with 25K miles.

Over the Christmas holiday, temperatures were around 20ºF overnight. After a cold soak, the vehicle makes a knock on start up. The noise goes away once the engine has warmed. Since this is the wifes daily driver, I never heard the noise before.

It sounds like my Sierra Z71 with Piston Slap.

Thanks,

Bobcat.

 

Had the same knocking/rapping sound till the engine warmed up in my '09 RX.
Fairly common and said to have no negative effect on engine.
I found that to be unbelieveable but said to be true..

 

Thanks for the reply. I guess it is normal. I'll still mention it to the service department at the next oil change.