Has anyone ever had a timing belt brake on a RX300? A serviceman told me he has never had to replace a timing belt on a V-6 Toyota engine because it broke. They made the belts too durable and long lasting!

 

That's the idea for recommended service at 90K-120K. Replace it before your stranded. The belt teeth wear off verses parting in half.

 

If the TB is broken, then you are SOL ... but the idea of replacing the TB at 90K is to prevent the belt from breaking which will cost you far more to fix. It is also a good time to replace the water pump while you are at it.

It would be nice if Toyota/Lexus uses timing chain like Nissan where you never have to replace or service.

 

1MZFE is a non-interfering engine, if the timing belt broke, you need road side assitance to tow to dealer but no damage is done on RX's engine valves. I also have not heard one case of timing belt broke so that is the last thing I will worry.

 

The reason why he has never had to replace a timing belt due to breakage, is because people who drive a Lexus take good care of their vehicles, and do preventive maintenance, which includes replacing the timing belt around 90,000 miles. It's something you must do, like changing the oil.

 

Almost forgot about the 1MZFE, and I could never remember when the interference VVT-i engine was introduced; at any rate, replacing the TB along with the tensioner pulley, auto tensioner, water pump, and all belts at around 100K add up to a small preventive maintenance investment IMO.

 

Preventive maintence is always cheaper but I think the reasoning maybe off. For example, just take a poll on how many Lexus owners actually replace RX's cabin air filter as owner's manual recommendates. I am giving that example because 1) it does not require any tool 2) step by step DIY instruction is in the user's manual 3) takes maximum of 5 minutes of time. This is not an insult but Lexus just have a different clientele...
Timing belt age by years not miles, Lexus just calculates an average of 15000 miles per year of a typical user, so 6 years is what Toyota believe 99% of the time owners have a working belt @ 90K. That is the main reason mechanic have seen water bump broke but never a broken timing belt. $1000 for a $25 belt is a joke, if I ever shop for labor, Toyota and a trusted private shop is my best choice.