Any idea what this noise is?

[ubersonic]

Hi all,

My car keeps making this intermittent noise as per video (between the 15-21 second marks), sounds kinda like a railway carriage clacking over joins in the track.

Any ideas? Loose/damaged cam chain? Imminent engine death? Wasps?

Also yes I know the engine bay needs a clean...

[ColinBarber]

Difficult to tell but worth looking around the exhaust manifolds for cracks - does it happen more when cold, when you rev etc?

Certainly not bad like this:

 

[Therickster]

Hi I would say cam variable adjuster problem, get it checked I believe there’s a electric control valve in there That can cause problems 

[Arnett]

Sounds like the variable emissions reduction system to me, according to google its a known problem easily fixed by installing a Hydrogen torque system behind the flux capacitor. Once installed run on electric for 1 hour every 20 hours driven Wala. Should sort it. 

 

Yeah Im talking poo, but I hope you manage to get to the bottom of it.  

[hockeyedwards]

2 hours ago, Arnett said:

variable emissions reduction system

Like VW's? 😂

[Womble72]

18 hours ago, ColinBarber said:

Difficult to tell but worth looking around the exhaust manifolds for cracks - does it happen more when cold, when you rev etc?

Certainly not bad like this:

 

I had cracked manifolds on mine, this isn’t the same type of noise, manifolds are noisy on start up and quiet down after a few moments as the metal expands…….one of my branches was completely snapped and only held in place due to the bolts, hopefully it’s not to expensive to rectify 🤞🏻

[ubersonic]

Thanks for the help guys, looks like I've managed to find the issue.

Came across this 6 year old vid of a guy with the same sound:

Which amazingly was still getting comments even four years later including from a Lexus tech who identified the issue.

It's a known issue with the left side timing chain tensioner on the ISF, GSF, RCF and many other Lexus with a UR series engine, they addressed it in Technical Service Bulletin EG-0031L-0516 (PDF attached) back in 2016 and replaced the part with a better designed one however the fix was never implemented on future ISFs as it was no longer on sale, and they didn't issue a recall as it's more of an annoyance than a problem (hence the guy in the above video having it for four years until he had it fixed).

So a ~£50 part and 7 hours labour, I wonder how much my local Lexus dealership are going to charge 😛

4b615dae112b39d84e0368a831eca731.pdf

[Texas]

Excellent find my man! And bear in mind you don’t have to pay Lexus dealer rates if you have a known specific job (with supplied genuine parts) you can go to any established engine rebuilders.

[ISF V8 JAY]

The noise definitely sounds like the tensioner, see if you can find a decent independent that can do it for you. **** load of seals to replace too. Can get the parts direct from lexus.

[Jez.w]

Hi ubersonic, what mileage is your engine in your ISF? Has it just started doing this? Is it just a high mileage related issue?

I wonder if the revised RCF engine doesn't have this potential problem as tensioners are improved where needed?