[Rust-O-Matic]

I had just enough daylight left after work to warm the truck up and take another quick look.

Of the 2 holes in front of the fuel pump Geezer asked about; the upper one has a bolt in it (but I don't know how long yet), and the bottom hole is empty. I put the stethoscope all over and around the pump, and there is definitely a ticking sound when touching the body of the pump, but I'm not sure if it's abnormal or not. When touching the engine block adjacent to the pump, I don't hear anything. I might just go ahead and replace the pump to be sure. It's old, and they're cheap.

While I was in there, I touched the 'scope to the alternator, PS pump, and water pump as well, and none of them made any sort of ticking noise.

Then I decided to take a closer listen to the valve covers again. When touching the stethoscope to the top of the valve covers in several different spots I hear nothing out of the ordinary. Just the rockers working underneath. When I touched the SIDE of the passenger valve cover though, it about popped my ear drums. The only spot I could hear this loud ticking was about 3" back from the front end of the valve cover, on the side that meets the intake manifold. I don't hear it anywhere else on that cover, or on the driver side cover at all. Now, when I say loud ticking I only mean loud through the stethoscope, it's so faint standing under the hood at idle I can't always hear it over the engine and exhaust hum. It's much more noticable in the cab when driving down the road.

So I guess my next question is, does anybody know what would cause a valvetrain noise I can only hear when listening to the side of the valve cover? I'm not even sure what to search the forums or Google for at this point. It seems really strange I can't hear it from the top as well. Is it possible the valve (or something related) has too much play laterally and is clacking side to side?