OKay I have an issue that is driving me nuts. When I run my truck I hear a knocking sound (is mechanical) that changes with the revolution of the engine. I have already changed out the plenum gasket, checked the exhaust manifold for loose bolts (all where tight) I even verifed the torque on the head. I have isolated it to the driver side of the engine.

If anyone has an idea my last recourse would be to think about rebuilding the heads which at 93,000 miles is something I do not want to condier about doing yet.

Thanks for your help

 

upper knock or lower

 

It sounds like it is coming from the upper, but not wholly positive.

 

have you done a tune-up lately. you should check the sparkplugs at least.

 

may need a new cap and rotor, i would do a full tune up brah, wires,plugs cap and rotor,

check your oil also

 

I didn't know guys wore them to.

 

rod bearings

 

listen to your valve covers with a mechanics stethoscope. That should help isolate it.

 

is the breather line hooked back into the back of the air breather? sometime with this rubber line out you can hear the noise comming from valve covers, and this is on drivers side....so just something to check out.

 

get a piece of pipe about 3 feet long to use as a stethoscope. i like to use 1/2" or 3/4" thin wall conduit, but anything will work.

BE VERY CAREFUL OF MOVING PARTS. place one end of the pipe against the engine and your ear against the other end. move the pipe around and follow the noise to its loudest point.

i also have a mild lower end knock that i can hear at idle, but not at medium rpm. its been there since i got the truck (4 years and 50,000 miles) and hasn't changed any. "knock" on wood.