My 2007 hybrid is still rolling at over 350K miles. I drive it 130 mile a day to and from work in SoCal so a lot of stop and go traffic. I recently started hearing a chattering noise coming from the engine only under low acceleration. when I put my foot in it the chattering goes away. I have a sneaky suspicion it's my timing chain, a buddy of mine said that it could be valves out of adjustment. My thoughts were if it was just the valves I would get the chattering all the time....even under hard load.

I figure that if I just bit the bullet and replace the timing chain it will take care of both scenarios, I search the forums for a how to on timing chain replacement. No luck finding anything. Anyone know of a good thread I can look at? I'm guessing a 4-5 hour DIY job.

 

At that mileage, you should have checked your valve clearance 3 times. Have you done so?

I agree it sounds a lot like a timing chain issue, but you shouldn't overlook the valves.

 

I bought the vehicle when it had 125K on it, I have adjusted the valves once, and when I do the timing chain it will be checked while I'm there.

 

The belt tensioner bearing on my car died this spring and made a lot of noise, especially at start up. Might want to look at it too, pretty easy to do, just take the big bolt lose, slide off the pulley & bearing and spin in your hand. You'll feel and possibly hear if it's gotten loose