5VZ-FE Tapping

I have a 3.4L 5VZ-FE in a 2001 Doublecab. It makes a light tapping noise at idle and it gets louder as the RPMs increase, independent of vehicle speed. It's more noticeable when inside the vehicle and moving, but definitely coming from the engine bay. Does anyone have any suggestions for what to look for, or how to diagnose it? I will be pulling my valve covers off in the next week or so to replace all of the seals, so I'll be able to see in the top if there's something in there I should look for.

 

Valve adjustments?
http://www.yotatech.com/f128/5vz-fe-3rz-fe-2rz-fe-valve-adjustment-tech-226997/

 

Time for an oil change? Or maybe someone put a lighter weight in it. Just a thought

 

It would be nice if that's all it is. I haven't changed the oil yet, since it's seeping out of the back a little. I think I'll try that first, and if that doesn't do it, I'll look at the adjustment in the link above.

 

Be aware, Toyota wants 5 bucks each for the valve shims.
That is the best I can find here in the West Coast.

 

See if you can narrow the sound down to the valve covers, or if it's elsewhere. My 1999 v6 has one drivers side valve that makes a light tapping sound, more noticeable when it's cold outside. As long as the valve clearance is within spec it should be fine. I just replaced the cover gaskets on mine a few months ago and spot checked a handful of valves and they were all in-spec, so I didn't check the rest. 180k miles on the truck at that time. When you replace the cover gaskets, also replace the spark plug tube seals and the rubber spacers that the bolts go through. You'll need the proper sealer for the half-moon shaped metal pieces as well. The Toyota FIPG sealant is great stuff, just get the parts surgically clean before applying the sealer.