RVH

I haven't seen this discussed, if it has please send a link.

I have 75,000 on my 2010 RX 350 and was thinking about the timing chain replacement. Looking in the manual it does not recommend replacing it!

What are your thoughts? Should it be replaced and if so at what mileage? What should it cost?

Clutchless

You are confusing a timing chain, which lasts the life of the vehicle, and a timing belt, which needs to be replaced periodically. There was another recent thread discussing this issue with regard to maintenance on a high mileage vehicle. Your timing chain does not need to be replaced, ever, unless it has a problem. Just change your oil on time and you will be fine.

RVH

Thanks, Clutchless, please send me a link to the other thread because I wasn't able to find it.

Is the "Drive Belt" a "timing belt"? Because a "timing belt" is not mentioned in the manual. A search for "belt" in the manual shows only:

Inspect the following:
___Axle shaft boots
___Ball joints and dust covers
___Body
___Brake lines and hoses
___Brake rotor thickness and runout
___Drive belts
___Engine coolant (RX 350; see page 28)
___Engine/inverter coolant (RX 450h; see page 28)
___Exhaust pipes and mountings
___Fuel lines and connections, fuel tank band and fuel tank vapor vent system hoses

It never recommends replacing the drive belt

Here's what the manual says about the timing chain:

Timing Chain
Your vehicle is equipped with a timing
chain that requires no periodic
inspection.

LeoDLion

There is a discussion about timing chain in this thread

https://www.clublexus.com/forums/rx-...elt-break.html

Apparently it is around 90k to 120k before you start thinking about replacing it. The Lexus is a non-interference engine meaning if the chain breaks, the engine is okay. Unlike interference engines where a break will bent the rods and you have to get a new engine. I have this happened on my BMW with a interference engine. I have to buy a new engine (actually used one).

The manual says the timing chain does not need periodic inspection. It does not mean it can not be replaced. There is no guarantee that it will last the life of the car. Personally I won't worry until I get 120k. Notice it is a chain and not a belt. A chain is made of metal and is more durable than a belt.

RVH

Thanks, as I was planning almost a thousand bucks to do the timing belt and water pump I think I just saved some money!

felix168

The belt on the your RX is the one that drives the AC, alternator, etc. It does need to be check periodically for cracks because if and when it cracks while you're driving, your water pump stops and your engine can and will get overheat and toasted.

Timing chains do break. Usually that has to do with the tensioner, water pump failure, and/or from people not changing the motor oil.

afpj

Wow, I thought nearly all Japanese engines were interference type.

Tom558

I hadn't thought about it much other than not needing to change the timing belt. The belt broke on our old Cressida and no damage was done, but I thought we just got lucky. Here is a list I found.

SteveCraig

Common issue with a chain is that on high mileage engines, or highly abused engines, they will stretch a bit.
Chain connects the crank with the cam & a longer chain will present as a poor running engine, hard/impossible to time, lack of power etc..
Steel chain is far more reliable vs. a belt.

My old Buick was a pushrod V8 with a chain. Factory used nylon tipped gears on the cam pulley to make it ultra quiet. Problem there was after a few years chunks of the nylon gears would suddenly appear in the catch basin & say "hello" as you drained the oil from the pan.

Anyone know if Lexus/Toyota is using a steel gear set or nylon ??

LeoDLion

According to the sticker on my car (which I saved) I have a 3.5 liter 275 HP V6 engine with VVT. It is not listed in that list. The closest is a 3.3 liter V6 and it is non-interference.

Again if one goes by mileage start thinking about replacing it at 120k (if one will keep the car that long). And while having it done, think about replacing other parts too like water pump, tensioner, etc.

CapSacto

Ok, to help clarify this topic....

1. Lexus RX 350 V6 motors 2010 and later have a Timing Chain that never needs replacing.

2. This motor does not have a Timing Belt

3. This motor has a Drive Belt aka serpentine belt that drives the alternator, water pump, A/C compressor. This belt is visible by looking down on it from above. This belt needs to be changed at the recommended interval of mileage or time in service, or if it becomes visually worn.

Hope this helps.

LeoDLion

CapSacto, I wish you were right that timing chain does not need replacing. Unfortunately like any other mechanical parts it is subject to wear and tear. It really depends on how you maintain the engine oil, how you drive, driving condition, some luck, etc.

Personally I will not replace the TC based on mileage. I will just let it go and when or if it ever breaks, I'll just have it replace.

Nelexus88

The timing chain guides often wear out before the chain does. This can create noise from the front of the engine where the chain runs and can result in timing gear damage if not corrected. Poorly maintained vehicles are more likely to have these issues.

123go

Shocking how people chance their timing belt/chain(s) to last past service recommendations.
I personally changed hundreds of belts/chains and 25yrs ago it was common to see a belt in rough shape at 60-80k inspection so you instantly realized its life was over.
Now days I rarely see belts looking worn out as they're made so much better now, well' China belts are trash and show wear, may even break at 50k. Buyer beware!
What I do see around replacement time or even past that time, are belts that are stretched and the tensioner totally seized (hydraulic) and/or spring tensioner just worn out but you cant tell this until you tear it all down.

This causes belts/chains to simply fall off pulleys. Being the p.o.c. we all know they are, my friend just towed his GM Aveo to the junk yard last summer.
First engine was destroyed around 65k miles on a trip out of state when its timing belt slipped off. A shop there put in a used 35k mile engine and the exact same thing happened again around 80k miles on the 2nd engine. Car was never driven hard, always maintained and no towing, all of which greatly shortens your belt/chain life.
It can happen to any car but my point is that's what I see more than anything.
Its not often a belt actually "breaks" since today's belts are as tough as chains, not seen one break within recommended intervals in several yrs. Ask a Harley rider what he puts his bikes belts through, Harley's ran belts instead of chains for many yrs now.

Timing belt driven water pumps tend to leak onto belts/pulleys making the belt slide off so beware when your antifreeze disappears. Toy/Lexus designed their pumps to not drip on belt/pulleys bad but older Toys did it. Most other car makes belt still get very wet and slide off so pay attention to your anti levels.
I've seen belts 50-75k miles past due still looking perfect but they are in fact bad.
I'll never push an interference engines belt/chain to its limits, sorry that's just not wise for anyone to ever do. My 07 4Runner (4.7 v8) hydraulic tensioner was totally seized with 95k miles when I changed it. I know its not a common issue but it only takes one time to destroy an engine over belt tension issues. "So' are you lucky punk?" Hey' Eastwood said it not me..lol
Personally before mine did it I had assumed what I saw from time to time was seized from lack of oil changes and I failed to look at the tensioner close enough to see if rust was on the plunger/stem making it seize or possibly interrupt movement because that's what my 4.7 did. A hammer wouldn't budge mine. Many seized are low mile vehicles as the tensioner don't move enough, belts weaken with age too on them so change it if its old. My knowing it happens regardless of oil changes I'll never leave a hydraulic tensioner on for another 100k mile round like many people say they do. Really idk what Toy/Lex states on the tensioner matter and I don't care after what I've seen. I'll happily spend the extra $50 for a new one every single time.

Chains stretch and generally rub on guides as already mentioned but if its not heard or simply ignored too long the chain can skip a tooth or even fall off its sprockets. Anytime after 120k a chain setup is on borrowed time. Personally I prefer timing belts because I know they are much cheaper over the life of the vehicle, they last nearly as long today and with no sprockets to buy with belts, today its much cheaper in the long run! People complained about belts, somebody listened and now stealerships make a lot more money. So be it!

Fwiw- All Nissan & Infiniti engines are interference engines regardless if chains/belt. The old Nissan 3.0 with belt costs $450 every 100k miles vs $1300 every 120k after Nissan updated it to Chain. Called its V6 a 3.5 after changing to chain but its the same engine. Yup!
Sorry long...

salimshah

Service recommendations are based on statistical analysis and somewhat adjusted for time (including weather cycles) and service intervals. As we know that timing belt/chain wear is based on engine revolutions and miles is just one indicator. My personal observation with Lexus timing belts is that they show little wear but the drive train of the belt wears out quicker during the recommended time for the T Belt. I have gambled on water pump on RX and SC and I lost on the SC. But it did not leave me stranded.

I would say follow the recommendations but feel free to over achieve.

Salim