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Toyota Sienna 2003 Timing Belt

How much risk is there to delaying the replacement of the timing belt on this car for another 2000 miles with 91,000 already?

The probability of breakage is very small, but the consequences are very large.

I just changed my 2002 Odyssey belt at 103,000 miles and it looked fine, but looks don’t mean much.

What does your owner’s manual say? 105,000?

Yes; the car is 7 years old and you have more than reached to mileage for changing it out as well. What is the actual risk? IF you are driving the car in a moderate climate (Western Oregon, Washington state), and do mostly highway driving, your risk is moderate.

If you live in Phoenix, Or Minnesota in the winter, change it yesterday. Anyway, you get the picture. No one on this panel will tell you to keep driving since you are already overdue.

The reason air travel in the developed world is so safe is because of a rigorous adherence to maintenace schedules and numerous inspections on the way.

I guess that a lot has to do with how much of a gambler you are.

I don’t have the Toyota Maintenance Schedule in front of me, so I am assuming the timing belt replacement for your minivan is supposed to be done at 90k miles or 6 years, whichever comes first. Please feel free to correct me if my assumptions are incorrect.

Nobody can tell you how long the timing belt will actually last before it snaps–with no auditory or visual warning. It could last for another 20k miles, or it could snap tomorrow.

The factor that you have to bear in mind is that your engine is of the “interference” design, meaning that when the T-belt snaps, valves and pistons collide–and that can cost maybe $2k-$3k to repair–over and above the cost of replacing the timing belt. So–maybe you will luck out with a delay, and maybe you won’t. Nobody can say for sure.

Incidentally, when you replace the T-belt–whether it is sooner or later–you should also replace the water pump, serpentine belt, and all belt tensioners. If you do not understand why I am recommending this, then post back for an explanation.

What is the actual risk?

If it goes, the engine stops right then, no warning no grace period. It likely will damage a number of internal engine parts, so at best expect an engine rebuild or a new engine.

Yea, you likely could drive a fair distance yet, but in my book, it is not with the risk.

Thanks guys. The recommended time to re-belt is 90, 000 miles. So I’m not too far off at the moment.

Belts are also age and environmentally dependent; it’s not just mileage. The belt and the car it’s attached to were likely manufactured in 2002. This means the belt is 8 years old and 6 is the limit in my opinion; especially on interference fit engines.
Maybe even less than 6 years depending on side issues such as extreme heat and cold, any oil or coolant seepage in the timing belt area, etc.


I guess that you missed part of my post, and a significant one at that, namely:
I am assuming the timing belt replacement for your minivan is supposed to be done at 90k miles or 6 years, whichever comes first.

Yes, you are not too far off, but unfortunately you are “off” in the wrong direction.
This vital maintenance is past due–by a year or more.

For some reason that I will probably never be able to figure out, a large percentage of people who ask questions about timing belts can’t seem to comprehend the “XXXXX miles or XXX months, whichever comes first” part of the maintenance schedule.

Next month, will you be one of those folks who posts a question like, “Is it worth replacing/repairing the engine on my 7 year old car after the timing belt snapped”?

According to the Gates page and older Sienna V6’s I’m familiar with, your 2003 engine is not an interference engine. If it breaks, your engine will stop whenever it happens. It might be in your driveway, on a local road, or between two tractor trailer trucks on an interstate.

Others will disagree with me, but I’ll go against the common reply on this one. I’d argue the odds are heavily in your favor that your belt will last another 2000 miles. I wouldn’t push it way beyond that, but the time/mileage recommendation is still in the “safe” zone for failure rates (before you begin climbing the failure rate bell curve).

The only real risk is totaling your Minivan or forking over $2000-$4000 for major engine repairs.

There is a factor of safety built into the timing belt interval for time and mileage.