Sound of chain rattle

Have a 99 Nissan Pathfinder, 99k on it…

many new parts…did change the timing belt last year. Hear a sound which seems to come from the back of what sounds lime a bike chain rattling. Any one knows what this might be? Anything emergent?

The check engine light has been on since last yr but mechanics told me not to worry, most likely the oxhygen sensor

Does The Rattling Noise Coincide With A Cold Start And Then Quiet Down Shortly After That ?

There is a TSB for hydraulic valve lifters.

The problem with driving around with your check engine light on indicating a code set by something like an O2 sensor is that if a different fault or faults develop, you’ll not be alerted.

Who knows if something else has gone south besides the 02 sensor circuit ? Get the codes checked again. Many large auto parts chains do this for free.


Without an inspection there is no way but to guess about rattles - LOTS of things can rattle. One common rattler though is exhaust system shields. This is normally not a big deal either in terms of function or fix. Have you actually looked and listened to see if you could tell what it is? A visual inspection is a place to start.

On the check engine light - oy. Those things come on for good reason and should not be ignored. Go to a big box corporate chain auto parts store. Many will pull your codes for free. Have them read, write down the exact code (like P1234) and post it.