I am getting ready to replace the timing chain and serpentine belt on my 2002 (187,000 miles) Toyota Prius. This has never been done on this car, so it's got the originals. Before I start such a big project and purchase parts needed I want to know if there are brands to stay away from AND/OR best to use? There SO many choices and I want durability over the cheapest I can find. Also any tips or tricks while tackling this project? I really appreciate any opinions or advise on this topic. Thanks.
Do you have any indication that the timing chain is in need of replacement? It is not a routine maintenance item as a timing belt would be. It would also be quite challenging to replace in the cramped underhood of a Gen 1 Prius. Out of curiosity, I once tried to position a hex bit in the timing chain tensioner access plug just to see if I could do it, and I could, but there was blood on my hand. Reinstalling the timing chain cover would require precise application of the form-in-place gasket, and proper placement and tightening of the cover, all in that cramped space, with no bumping or contaminating the bead, within a small number of minutes. It would be a much easier job with the engine removed from the car. If it were mine, unless there is a known problem with the chain, I would spend 15 minutes replacing the serpentine belt, and call it a day.
I’m with Chap. I have one over 300,000 miles and two pushing 300,000 and aside from the fact that I have not heard any noise indicating a need to change the timing chain, I’ve never heard of it happening on one.
My old Gen 1 started doing that too, around 198,000 miles. Never did figure out why. Had a close encounter with an eastbound Dodge Dakota 36,000 miles later, which made the mystery moot for me. Timing chain was one of the possibilities a mechanic had suggested to me, and valve clearance was another that I looked into. Because of the way the 1NZ engine is built, dropping in a replacement engine would have been less fuss than either.
Sorry to hear about the collision, hopefully the vehicles were the only ones that paid the price. You mentioned valve clearance, did you rule that out?
Try changing the plugs first and look for signs of a leaky injector. My sons was doing some rattling, in the beginning it was just at start-up. If you see signs of fuel leakage around then you’ll need to chasing out the rubber seals.
The details can be followed in the thread I linked above. I did not find anything that stood out as a smoking gun. On the 1NZ engine, valve clearances are easily enough checked. It's only if you see a reason to adjust them that engine replacement becomes the simpler prospect.
