2007 Camry V6 Ticking

When the engine of my 2007 Camry LE V6 is cold, it makes a ticking/knocking sound. The engine has 100,000 kms on it (60k miles). The frequency of the sound varies with the speed of the engine, not with the speed of the car.

When engine is cold: The sound happens roughly twice a second when the engine idles (at 700-800 rpm).

When engine is warm: The noise is less audible. It can be heard when idled at a stop, but you have to listen for it. The noise cannot be heard on the highway.

The car doesn't burn oil, and the oil level is ok. I had the oil changed 3000 kms ago, and it is still very clean (clear). The was the same before and after the oil change.

I am wondering if it could be the lifters, bad plug, or maybe a timing issue. Has anyone else had this issue?

I think the most likely problem is with one of the valve lash adjusters. It may be frozen or may have air in it.

Locate which bank the noise is coming from. Remove the head cover and see if any of the rocker arms have any play in them when the engine is cold and the cam lobe is placed on the opposite side of the cam from the lash adjuster (lifter). You will have to take a wrench and turn the engine (clockwise facing the front of the engine) until you can test all the rocker arms. If one has a little play, you can try filling the lash adjuster with oil. You may have to replace it.

To get any air out of the adjuster, put it upright in a can of clean oil and press a thin long punch into the hole straight down in the top of the adjuster and push down repeatedly on the check valve ball inside the adjuster. This should get any air out of the adjuster. If the ball valve won't move, I think you will have to replace the adjuster. There may be a way or resurrecting the adjuster if its stuck, but I don't know what it is.