Quick, loud, and very noticeable.

What is it?

BTW, I know its not the click of the DI

 

If it's a 250, worn cam gears. Covered under the original powertrain warranty, otherwise about $2400.

 

I have this on my 2008 IS250, and the Lexus dealer said it could be the oil filter. I have yet to replace it, but will see if that fixes it. I doubt it could be the cam gears, as it doesn't happen all the time for my car. It generally happens on warm starts for some reason, rather than a cold start.

 

It's intermittent on my IS250 also but was diagnosed by the dealer as the worn cam gear issue. Can't imagine how an oil filter would cause this?

 

I doubt its a oil filer as well. Did you get your car fixed? and if so did the noise stop for you?

 

It doesn't do it when its warm, only cold. Last for about a second, but its there

 

Reminds me of my dad's old MG where the oil pump was all gunked up or something like that. I was about 12 years old, but I distinctly remember hearing all the valves/cam clicking loudly right after a start-up and then it would silence down as the oil thinned. I remember he decided to rebuild the engine at that point so I don't know exactly, but if it's only a short-time after a cold start-up, then I would suspect oil flow being slowed and not coating the cam well until the oil coats them adequately. So it is possible the diagnosis of a sluggish oil filter could cause it. It's cheap enough. Change it and see.