2000 Volkswagen Jetta Timing Belt

Yes. I believe you have what's called an interferance engine. If the timing belt failed, a piston (or several pistons) could smack into valves that are still protruding into the cylinder and cause severe damage. A non-interference engine (those lucky guys that have them! :mrgreen: ) would just stall and spin down without damage when the belt breaks. Generally it's recommended that you replace the timing belt around 80,000 - 90,000 miles. I don't like to go much above 80,000 miles, especially if i don't know how the previous owner treated it. I have heard of a honda civic that went to 130,000 miles before the belt broke.

Unfortunately there is no sure way of telling whether the timing belt has been replaced. It is fairly labor intensive for any car with a timing belt... with the right tools, dedicate about a day if you want to do it yourself. A shop will charge you several hundred dollars to do it for you and most likely recommend that you replace the water pump as well since it's right there next to the timing belt. Water pumps have a lifespan too.

I call it preventive maintenance. It's just one of those things that needs to be replaced occasionally in order to avoid having to replace the engine.

why wouldn't they make all engines non-interference? also, i have read to replace the timing belt tensioner at the same time? yes, no? and the water pump, what is the typical life on that? this maintenance seems to be getting out of hand for a car that's worth $5000, not counting the check engine light on that I posted in another question.

There are advantages and disadvantages to non-interference engines. One major disadvantage based is that they tend to produce less power everything else being equal.

I'm not sure on your vehicle, but on some vehicles, the timing belt tension is preset at the factory, and when the belt is replaced later during the vehicle's life, it is required that you go and purchase a special item... normally some kind of spring, that will reset that precise tension. That is important or you could risk having your new belt break soon after it's installed. You can normally get the item from a dealer or a shop that does your model of car. Double check if that's the case for your vehicle, and replace it if it's required or recommended.

I would say that a water pumps lifespan is probably about the same as the timing belt. I would be very surprised to hear of a water pump lasting 180,000 miles, or about the time you'll need to replace the timing belt again. It will most likely fail between now and then. I hope this helps.

is there a way to check the timing belt without replacing it? does it take a while, or even can a garage check it? I don't want to go through the process of changing it and have them say, oh, this belt is in great shape. thanks

The easiest way to see the timing belt is to pop off the top timing belt cover (normally plastic) and take a look at it at the point where it curves over the top of the cam gear. Normally when they fail, the inner teeth strip out rather than the belt dramatically snapping in half, so check the inner teeth well. There is no sure way of telling a new timing belt from one that's at the end of it's lifespan... even the teeth will look fine in most cases.

Check it carefullly, have others look at it and give you their opinion. If you have good reason to believe it's the original belt, replace it. Even if it seems to be in tip top condition.