I am hearing the strangest noise from my engine. I first thought it was a rod knocking. I have heard it before and the frdequency was consistant with the piston movement. I don't hear it when I first start it in the morning. It seems to need to get warm first. If you slightly accelerate you hear it but when you let off it stops. I took it to my mechanic for a second oppinion. He was convinced it wasn't a rod knocking because you would hear it first time it starts untill oil got to the bearings. We then took the serpentine belt off and started it. The noise was gone. We both looked at each other. I couldn't make the noise again. We put the belt on again and the noise was back. The truck runs fine, 25 mpg, doesn't burn oil.

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2004 Ranger. 4 cyl white 5 speed. no bells or whistles. Its my work truck and just got it two weeks ago.

Pull the belt back off and spin each pulley.

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98 ford ranger xlt ex cab 4.0 v6 auto trans