Hey all

I've got an 04 that recently started rattling the timing chain. I figured it was the tensioner, bought a new one, put it in, and voila! All better. I pull out of the driveway an hour later and the rattle is back.

I replaced to oil to make sure it's at the correct level. I have it at the middle of the dip stick because my driveway has a slight incline. After replacing the oil, I started it back up (cold engine) and it did the same thing. Went away, then came back and remained.

Checked the oil pan, there's nothing in there.

Anybody have an idea of what could be wrong? Could it be the oil pump gradually breaking or is that an immediate event?

 

The chain tensioner has a ratcheting mechanism to some degree so it doesn't retract when oil pressure is lost (at least not immediately.) Oil pumps can wear out gradually and plenty of other issues can cause low oil pressure.

A few questions for you:

Any chance you have a broken chain guide? Replacing the tensioner won't do much good with a guide out. I'm doing an engine rebuild right now and found part of my chain guide was snapped and not doing anything, but still hanging together somehow. It might be possible to inspect the guides from above with the valve cover open.

Would you feel comfortable checking the oil pressure? I believe there is a plug that can be removed to attach pressure meter. The oil light only comes on when the oil pressure is dangerously low; I would say that's a good thing to check for.

Are you sure this is chain death rattle and not another timing component going out? Lash adjusters not getting significant pressure can sound like one might imagine chain rattle to sound like. I have made that misjudgment myself once, so I couldn't fault you.

Best of luck!

 

Try to pin-point the source by using a long piece of wooden dowel rod to your ear or an automotive stethoscope with a long probe. Be careful of moving parts (serp. belt, pulleys, etc.).