Lexus'05 Phase 3 GS300 - Valves coked up? Diagnose & remedy

[Prof Prolapse]

I have a 2005 (phase 3 Soap bar shape) Lexus GS300 which I believe has direct injection. Currently at 115,000 miles.

After a frankly incredible run of reliability, it's started to use a little oil (~150ml/1,000 miles but TBC). It's also started slightly noisy tapping from cold, this goes away once it's warmed up. On rare occasions it was a bit rough at idle, I'm unsure whether this is simply slightly low oil. I'm currently monitoring to see if it's using coolant.

Is there a way to diagnose coked up valves without removing the heads?
Is there a cost effective way to remedy this? The car is worth about £2,000, and I have little time to repair it myself.

I am keeping an eye out for HGF, and timing chains/tensioners. But all of these problems effectively write off the vehicle sadly.

Advice appreciated thanks.

[anonymous-user]

Do the tappets need adjusting manually? My LS430 had them done at the same time as the cambelt as they are non self adjusting. Not sure about the 2jz.

For sure though Beijing a Lexus it won't be anything major.

[stevieturbo]

Only way to check, is a visual.

Whether that's by removing the intake or associated parts, inserting a camera to look inside....either or.

And depending on miles, condition etc etc....having injectors tested may do no harm.

[paintman]

Quick google produces this from a Lexus owner's forum which suggests that these are known for a ticking noise from the injectors.
https://www.lexusownersclub.co.uk/forum/topic/5517...

ETA But tappet noise of that nature is common on higher mileage RV8 engines. I wonder if a thicker oil - staying within what's recommended for your engine - might be of help?

Edited by paintman on Friday 18th October 17:34

[Prof Prolapse]

Thanks for input all.

Hasn’t done it for last 50,000 miles and stops where warm so doesn’t appear to be injector issue.

I don’t believe the tappets require adjustment. I would be very surprised if it did.

Thicker oil seems unnecessary if it resolves when it’s cold.

I can get an endoscope on my mobile I guess...

[anonymous-user]

If it hasn't done it in the last 50,000 miles then I can't see what the issue is.

Keep on top of routine servicing and it should be fine. (The 2jz does need tappets adjusting manually from time to time though)