Kjell

Hello,

I have a 2013 Lexus LS600h. Facelift model, 208.000 kilometers. I am very happy with the car but I now hear a noise on a cold start that I do not trust. The rattle lasts for 1 second and then the car runs normally. I don't notice anything while driving. I have added a video. At first I heard the sound very occasionally but now I hear the sound more and more often.

According to my regular garage it could be the timing chain tensioner. But I called 2 Lexus dealers and they have never heard of this with this car.

What do you think of it?

Thank you in advance

Kjell de Vries

dan25man

Hello, yeah that's probably one of the chain tensioners (there are 3 in this car). I think for the LS460's there is a TSB out for replacement of the No. 3 (drivers side) tensioner. I had/have a similar rattle on mine. I put some Seafoam in the oil before my last oil change to clean out the oil passage ways and that seems to of helped but yea on cold starts it'll make a tick or two until oil pressure builds up.

Normally tensioners have a ratcheting mechanism that prevents it from loosening. So if that failed then you chain has slack in it before oil pressure builds to re-tension it. It's also possible the chain is stretched too much. There's a Lexus spec for how much chain stretched is allowed. But I don't have it on hand. IIt's in the 460 forums somewhere.

It's safe enough to continue driving the car but just don't rev it to high heaven before it's warmed up or you could skip a tooth in the valvetrain.

Shakka65

Hi Ive had the same noise. How many miles since last oil change? I found that after a fresh oil change this didnt happen so much for me. Instead of leaving a year I'd change every 5000 miles or six months. Ive got the same year.

Tdes395

Did you ever find out what was?