Ray O RX300 timing belt

I am not aware of any premature (time and mileage) timing belt failures. What model year is your RX?

The sludge problem starts with extended oil change intervals, which results in blacker oil, which neglected long enough, will result in sludge.

Ray, It is a 1999.

Nick,

How long, time and mileage, until 60,000 miles?

If you are concerned about the condition of the belt, you might be able to loosen the upper timing belt cover enough to sneak a look at the timing belt's condition.

Unless a pulley or water pump seized up you're probably not going to see a belt failure before 60K miles or even 120K miles (some owners to

It would be a good time to inspect or just simply replace the oil seals, water pump, valve cover gasket set, PCV valve/grommet and pulleys at the same time. But you may be able to do that every other timing belt, depending on the condition of the components.

Sure, blackened thickened oil is the start of the oil sludge problem. The problem is the higher cylinder head temperature Toyota needed to pass newer emissions standards. So while traditional sludge starts in the oil pan, Toyota sludge starts in the cylinder head. You can inspect the oil passages while the valve cover gasket set is changed.

As a result of the sludge problem in 2004 ALL Toyotas are required to change oil every 5000 miles instead of the 7500 miles earlier to maintain warranty.

I think that 12 years is kind of pushing it as far as trusting the original timing belt. I think that it would be worth the time to remove a few bolts that hold the upper timing belt cover in place and take a peek at the belt. If you see cracks on either surface, glazing, metal strands showing, etc., then go ahead and have the belt replaced.