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2004 Toyota Sienna V 6

Gates says that this is a NON interference engine. I have seen where a couple of dealers say this also, but almost everybody else says it is an interference engine. If Gates says NON, wouldn’t they be responsible if someone chose to take their advice? What is a normal belt replacement cost for this vehicle?

Why would Gates be responsible if your timing belt broke and destroyed your engine? I don’t even get that logic. Their timing belt guide contains no “advice.” It most certainly can be wrong, but that’s frankly irrelevant.

The timing belt question comes up all of the time. It sounds like you want to skip the service and you’re trying to find out how much trouble you’ll end up with if the belt breaks. Well, if its a non-interference engine you might have no difficulty at all. Wouldn’t it be nice if it broke in your drive-way just as you got home? What if it breaks at 70mph with a tractor trailer bearing down on your rear bumper? In the middle of the night? In the middle of no where? While you’re rushing to…wherever you might be rushing to. The belt won’t warn you. It won’t make any noise. The car won’t do anything funny. It will just break and your van will immediately stop running. You won’t have power steering and you might have power brakes for maybe one or two brake applications.

Almost no one here is going to tell you that this is a good idea. Get the whole job done - the “whole job” usually includes a new water pump & tensioner at minimum. It will probably run you anywhere between $600-1000. Call around to local shops for quotes.

Your posting is a pretty good posting, cig.

The only thing I would add is on my 2002 Sienna the recommendation is to “inspect” the water pump when the timing belt is replaced. At only 90,000 miles, if, and that is a big if, the cooling system has been properly maintained, it is very unlikely the water pump will fail inspection.

Now, maybe you know dealers who turn away a chance to do expensive repairs, but I do not. And, the dealer said my water pump was fine at 90,000 miles.

I do plan on replacing mine next fall, because if I drive it a lot more, it is assumed it will eventually go bad, though I am only guessing. If I replace it at 180,000 miles, it should never need replacing again. That is part of my high rel maintenance program.

The Gates Timing Belt guide on their website lists the 3.3 V6 (3MZ-FE) as an interference engine. My wife has an 06 Sienna with the 3.3 V6, I’m not willing to take a chance that the V6 is non-interference. I will have the belt and water pump replaced at 7 years.

Ed B.

You have the 3MZ-FE engine, which is interference.

For the earlier 1MZ-FE engines, there were two flavors. The earlier versions (without VVT-i and with the lower horsepower) had non-interference engines. The later 1MZ-FE versions (215 hp with VVT-i), were interference.