Knock knock (1 Viewer)

[ff347]

So I will try and upload a video with sound tomorrow.


I have an rpm dependent knock/tapping even with the vehicle sitting still starting at 2500. below that the engine is quiet (reasonably) for a 2f.
The facts-
truck was down for about a year. Vacuum is good, not blowing oil and none In radiator. Desmogged with jimc idler, newer water pump,alternator, fan clutch and I put a screwdriver on all of those to hear them, a/c compressor is quiet also.
It pulls strong with no crazy temps etc.

I am sure the video will help a good deal for diagnosis. But for now I will take knowledge from the mud pool.

 

[ff347]

So this is one video, with earphones it sounds more like a rattle?

 

[Output Shaft]

Remove all the belts.
When the engine is stone cold in the morning, start it up and quickly listen for that noise.
If you still hear it, turn of the engine immediately.
If the noise is gone, turn off the engine immediately.

Replace the belts. You can idle a cold engine without the water pump circulation for a short while.

If the noise is gone without the belts, then one of the ancillary components are bad. Alternator, AC clutch or idler bearing, smog pump eliminator pulley, or power steering pump.

If the noise is still there when the belts are removed, then the problem is in the engine.

 

[ff347]

That sir is an excellent idea! That's why I asked for that kind of problem solving.

 

[ff347]

In another video the belt to the alternator looks kind of loose, just noticed it.

 

[ff347]

@Output Shaft

Thanks as always you were a big help, took the belts off and it is the water pump. I could spin the fan blade hard and here the belongings of the tapping sound. with no belts the tapping is gone.

 

[ff347]

Update, been busy but I got to taking off the water pump and found the real culprit. The water pump pulley was loose, never reached back there and moved it. Spinning the fan started the clicking but thankfully that is all it was. Now I did have to locate another pulley locally but that was easy, one call to @Trollhole and had a new pulley with an actual circular bolt hole pattern. Swapped it out and done, noise gone.
I guess the message is thanks MUD!