Timing belt question

I own a 1999 Olds Silhouette with 100k. The maintenance book makes no mention of timing belt change. Does this car have a belt or a change, and when should I replace it? Anyone know if it has an interference or non-interference engine?

Which engine?

If this van has the 3800, or 3400 v6 motor(and most do), it has a timing chain, which you don’t replace unless it breaks(which it probably won’t do til the engine is worn out anyway).

Look at the front of the engine, if a front wheel drive, look at the end with the belts. If there is a (usually black) plastic panel about the size of a briefcase, maybe a bit smaller on the end of the motor, that’s more than likely your timing BELT cover. If there is no such panel, and all you see is the valve cover sitting on top of the head, you’re more than likely looking at a timing chain engine.

If you’re the kind of person who’s willing to try anything (like doing your own timing belt or chain, go to your local car parts store and get a Haynes or* Chilton’s* shop manual for the car. It’ll tell you whether or not you’ve got an interference engine.

'course, you can take it to a mechanic who’ll be able to tell you with 100% certainty if you’ve got a belt or chain. And they should also be able to tell you if you’ve got an interference engine. For the cost, you might consider having a mechanic “just do it.”

My books show only the 3.4 engine in a '99 Silhouette. It’s a timing chain design.

While I have a book that indicates whether or not timing belt engines are interference types, I haven’t seen similar info for timing chain engines. Generally mechanics who have a lot of experience on a particular engine will know. It’s a somewhat moot point in that chains don’t generally fail suddenly the way belts do, although it’s not impossible to have a chain-related failure that will bend valves on some engines. It is usually possible, however, to get an idea of the degree of wear on a chain set-up by observing the slack between crankshaft movement and corresponding camshaft movement. This is easy on an engine with a distributor, difficult on a distributorless one.

It’s not a bad idea to replace the timing chain and gears at about 150K miles for prevenative maintenance, but it’s hard to make a blanket recommendation due to the variations among all the different timing chain engine designs out there, as well as to variations in specific wear factors for a particular engine.

It is the 3.4 V 6. Thanks for the information. I know it’s a matter of weight, noise, and money, but it really seems like everyone should go back to the chain rather than belt. I know I’m glad to hear that mine has a chain. I think Nissan has reintroduced it on it’s cars, and use it as a valid selling point.