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Timing belt & water pump

Good morning,

We have a 2006 Toyota Sienna LE,with 108,000 miles. We service it without fail every 5,000 miles. The mx book, and our service center, RECOMMENDS a new timing belt, and water pump at this time. Our friend, who is a mechanic says not to do anything until we see water leaking. The cost to change now is 500 plus, and I guess a whole lot more if we wait “till it’s broke”. What is your suggestion?

Thank you for your help in this matter.

Change both. Timing belts are wear items and need to be changed on schedule to avoid larger repairs down the line. It appears your vehicle has an interference engine, making a timing belt failure very expensive. Changing the water pump is preventive and costs very little to do when the timing belt is done. Risk is that the old water pump could go later, causing a similar labor bill as for the timing belt change.

I would recommend following the manufacturer’s service book. If it is leaking water that is the water pump failing, unfortunately if the timing belt fails there is no real warning, just a very expensive repair.

The timing belt service interval for an 06 Sienna (my wife’s) is 7yr/90k miles, whichever comes first. Your van is 18k overdue. The 3.3 6 cyl is an interference engine, a timing belt failure would be catastrophic and the cost would be thousands not hundreds. Is your friend willing to pay for a new engine if the belt breaks?

I would have the belt, tensioner, waterpump, and any other related parts replaced ASAP.

Ed B.

I don’t think this 3.3 liter V6 is an interference engine. What does your owners manual say about when to change the timing belt? You should think about doing this work in the not too distant future, but don’t worry too much about it.

I can't make a specific recommendation because not all Toyota's have the same recommended maintenance interval.  I can recommend:   [b] Do nothing less than what is recommended in the owner's manual[/b].  Don't assume that what is good for one Toyota is good for others.  Failure to follow the recommended (by Toyota Corp, not the dealer) can be rather expensive.  It is cheaper in the long run to do it as recommended.

Thanx, Ed for your reply. Are u a mechanic? I thot I would hear from one of the car talk “guys”.

How much do u think replacing timing belt/water pump will cost? We have been quoted 500+

It’s not an interference engine, but it does appear to have a timing belt as opposed to a chain. I’d replace the belt now, rather than have it break at an inopportune moment. marta, the water pump is usually replaced at the same time because you have to remove it to get at the timing belt. The pump is not all that expensive.

According to this is NOT an interference engine. So all that will happen when the belt breaks is it’ll leave you stranded…which could cost you a few bucks to be towed…and hopefully it doesn’t happen on the highway during rush-hour.

When replacing a timing belt it’s a good idea to also replace the water-pump since if the pump fails you’ll have to pay to have the belt replaced again. The biggest cost in replacing the timing belt is the labor.

The advice your friend the mechanic gave is dead wrong for sure.

from the many many times this question has been asked here 500 bucks is not out of line, and the problems you will face if you dont follow the service intervals are much more expensive.

It is not an interference engine, thie means a broken belt will stop the motor, you will have to find a safe place to pull over, stop and call for a tow. When the motor stops you will have normal braking to make a controlled stop, you will not have power steering but should be able to steer off the road with little problem. If this happens on a busy interstate highway, on a bridge, in a tunnel, or overpass it could be kind of dicey with traffic wizzing by or no place to pull the car safely off the road. Timing belts don’t break in the driveway and you can’t predict it. No special noise or smell, they just let go all of the sudden.

If this scenario makes you uncomfortable get the timing belt changed, and $500 for a new belt water pump and assorted tensioners seems reasonable. A broken belt will not damage the insides of your motor and you won’t have to replace bent or broken valves etc.

Tom and Ray don’t post here. I am not a mechanic, I just try to learn as much as I can about the vehicles in my family.

I’m going to stand by my assertion the 3.3 V6 (3MZ-FE) is an interference engine. The Gates site lists it as interference in the Application Guide, but it comes up as non-interference in the “Got an Interference Engine” link under the applications guide.

The consensus on Toyota specific forums is that it is an interference engine. For example,

I’m going to stay on the safe side and assume it’s an interference engine and change the belt and water pump on my 2006 at the recommended interval. It’s not something you want to learn the hard way.

Ed B.

Thank you all very much for your input. Guess we’ll bite the bullet, and get 'er done!

Interference engine or not, if it were mine, with my luck, it would break down in the middle of Roxbury on Blue Hill Ave on a dark and rainy night. Or in the middle of a terrible blizzard.

I’d get both the belt and the water pump changed. It’s due.

Exactly. There are so few good places for a car to break down: On your way to work when your boss has told you not to be late to work again. On your way from work when it’s dark, the weather’s bad, and antsy commuters are crowded on your rear bumper. On a first date. On an anniversary date. When you’re driving through a dodgy area of town. When you’re out in the middle of nowhere on a long road trip. On your way to an airport for flight that will take you on the cruise you’ve saved a year or more for. . . .

$500 to $700 seems to be reasonable in my area (Kansas City)