New Owner Advice Timing Chain

[REANIME83]

How often is it recommended to get the timing chain changed on a IS250...mileage or years...

My "new" Lexus has done 77000 on a 08 plate.

Many thanks in advance.

 

[NemesisUK]

I thought if it was a chain, not a belt, there is no requirement to change it unless it's rattling and showing signs of stretching? 

[normski2]

4 minutes ago, NemesisUK said:

I thought if it was a chain, not a belt, there is no requirement to change it unless it's rattling and showing signs of stretching? 

+1 to that, exactly so.

[REANIME83]

No issue with mine at the moment just curious.

Had cars in the past that have specified it to be changed at certain mileage etc. (belts as opposed to chains)

Thanks for the input. 

[NemesisUK]

Do you have the service book for the car? 

[johnatg]

The most critical thing affecting timing chain (and tensioner) life is good quality, clean oil. If you use the correct oil (fully synthetic 5W-30) and change it at 5K mile intervals from now on (twice as often as Lexus service spec) they will last more or less indefinitely - 200K miles or more.

And by then, it is unlikely to be an economic proposition - it's a pretty expensive job to do yourself (think 4 figures) and will cost well more than the car is worth at 15 years or more to have done professionally.

[REANIME83]

1 minute ago, johnatg said:

The most critical thing affecting timing chain (and tensioner) life is good quality, clean oil. If you use the correct oil (fully synthetic 5W-30) and change it at 5K mile intervals from now on (twice as often as Lexus service spec) they will last more or less indefinitely - 200K miles or more.

And by then, it is unlikely to be an economic proposition - it's a pretty expensive job to do yourself (think 4 figures) and will cost well more than the car is worth at 15 years or more to have done professionally.

great advice thanks!

[Fishboy]

Don't worry it's a Lexus not a BMW

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwj90-n86NbSAhWIDcAKHShUDXkQFggsMAE&url=http%3A%2F%2Fprestige-german-engines.co.uk%2Fengine-issues%2Fbmw-timing-chain-failure%2F&usg=AFQjCNG2BNYSdbm4JzbFiEVvPP6jtGHCxA&bvm=bv.149397726,d.ZGg

[Linas.P]

11 years on, the case of Lexus is chain snapping is yet to come. I am sure some guys in US had covered 300k miles without issues. I believe eventually we will have case of snapped chain somewhere, but at the time car will be worthless anyway.

Actually, I am quite surprised by BMW topic, I though by now most of engines are non-interference and valves does not cross the patch of pistons anymore not in BMW diesels that is... 

[Shahpor]

A friend of mine has a 2008 118d BMW that had this timing chain problem.

What drove BMW to install the chain at the rear of the engine is beyond me.

Anyway, his car also needed a new dual mass flywheel, 2 injectors and engine mounts at the same time.  Total bill was £4500!

[Fishboy]

Probably down to quality control issues with the chain manufacturer rather than the positioning with the engine design

[Shahpor]

I didn't actually mean the position of the chain contributed to its failure

What I was bemoaning was the fact that it meant taking the engine out to change it rather than just the front timing cover.

[johnatg]

It's not really snapping that's the issue at big mileages (although it can happen) - it's stretching of the chain, along with corresponding wear of the tensioner and the sprockets. That leads to excessive noise. This problem will rear its head more and more with stupid extended service/oil change intervals - the wear is largely caused by ineffective lubrication when the oil gets contaminated.

I'll say it again - frequent oil changes!

(BTW - IS250s have three chains - the main one which drives the intake camshafts and two small ones, one for each bank, which drive the exhaust camshafts from the intake ones.)

[Shahpor]

I agree John.

I personally think it is madness to service a car only once every 20k miles or so.

Yep, it has been a while since I have heard of a chain snapping.  In the case with my friend, the chain stretch had worn out the sprockets on the cam gears as well, and it had jump a tooth or two, causing a misfire.

Still, it wouldn't be a huge job if the chain can be removed from the front without having to remove the engine, unlike the affected BMW's.

[Linas.P]

14 hours ago, Shahpor said:

I didn't actually mean the position of the chain contributed to its failure

What I was bemoaning was the fact that it meant taking the engine out to change it rather than just the front timing cover.

That is because "by design" it should have never be replaced, but reality is different as we know.

Have anyone actually heard of one snapping on IS250 yet?