I have only two suggestions belt related. Have you checked the timing belt adjustment. You just loosen and retighten to let the tensioner reset.

I figure you may have replaced the belt sometime ago. May need ajustment again.

The tensioner usually make a whining noise when they get dry.

Alternator bearings rattle a tiny bit.

Power steering pumps sound line steel ball in a quart sized paint can on the older non-remote tank models.

This clicking is it a metallic sounding tapping or clacking or a soft rubbery deaden thumping? Geez, this is hard to write! I was thinking of the crank pulley dampener and mounting bushing for the components.


The next could be oil related. Oil pressure could be changing or the amount around the cam. Drain back could be slow. At higher speeds the amount could dampen the clicking "if" its valve train related?

Did you do the hose to the ear trick and it up with it on top of the noise.

This thing must be faint yet you hear it while driving. This is the puzzle part of your post.

You may want to invest in a mechanics stethoscope or borrow one. It might give you a more in depth sounding. They are good for the small on the inside noise. When you hear it down deep then you have to relate that to what you think you are hear outside. If that makes any sense?

I have listen to the injectors that you can't haer clicking or at least I can't with other engine noise. They sound like a jack hammer with a metallic ringing echo! When you hear them that way. You wonder how they last as long as they do. Then again, all is tiny in there!

Hope this get you closer to it. You may have to sleep with this, Gal yet!

Phil