SILVRLININ

iTrader: (5)

I've done the search to no avail...This question may not have been raised as most of the 2IS owners have fairly low mileage. Can anyone personally recommend an ideal time to change the belt?

Thanks in advance,

Koz

From what I understand the 3.5 is a non-interference engine, which means, if there is a failure the engine is not damaged.

Koz

Bichon

Our engines don't have a timing belt, they use a timing chain, which requires no maintenance.

As several members who've encountered engine damage from broken valve springs can attest, this is not true.

SILVRLININ

iTrader: (5)

Thx! Mods are welcome to close this thread

Koz

Being that a chain is used (which I knew) I assumed it was non-interference. Thanks for the clarification.

Someone had a chain failure and bent valves or damaged pistons? I have never read of this happening.

Koz

Evitzee

Haven't heard about chain breakage, but broken valve springs have caused problems for some owners.

Koz

I've had the valve spring recall done. Valve springs breaking has nothing to do with whether an engine is non-interference.

Koz

Bichon

Not true, Koz. A broken valve spring will not retract the affected valve out of the way, resulting in repeated valve-to-piston contact in an interference engine like ours. Bad news, though not nearly as bad as when a cam is holding the valve open on an engine with a broken timing belt, or a broken cam actuator, as happened to this poster who experienced $4400 in engine damage:https://www.clublexus.com/forums/5782892-post235.html

I'm not sure where you got the idea that our engine is a non-interference design, but you are definitely wrong on that point.

Koz

You cited one failure that was not even verified as what caused the failure. I'm sure if what you say is fact we should see more then one. Also I'm not sure as to how accurate this post is but he seems to be pretty knowledgeable about what he states and he claims the engine is non-interference. I also believe it to be, unless you/someone can provide technical data that states it isn't. I wiil try to get an answer from Lexus.

https://www.clublexus.com/forums/5789780-post238.html

Koz