[shedevil]

i was driving on the freeway tonight and heard a snap then a rapping sound.it sounds almost like an exhaust leak but im not sure.when i hit my gas it gets louder and more rapid.when not hitting the gas it is there but erratic and quieter.i havent been able to look very good at it cause its dark but i couldnt see anything obvious.any ideas?

 

[Guest]

Hard to tell, but it could be an exhaust manifold leak or the air pump hard lines to the heads. Mine rusted thru and caused a sound something like that. On mine, one of those lines crosses behind the heads. That's the one that rusted thru. Sure you didn't just run over Puff Daddy?

 

[shedevil]

Sure you didn't just run over Puff Daddy?

i wish that was it but i diont think so.where exactly is that hard line? havent been able to look yet.

 

[Guest]

There are rubber hoses running from the air pump to hard lines on either side of the motor, near the valve covers. Where these hoses connect to the hard lines are one way valves. The drivers side line connects to a teed hard line at the rear of the motor. This line connects to the rear of both exhaust manifolds. The passenger side connects to the passenger side exhaust manifold near the header pipe. When the hoses or lines break, it sounds like an exhaust manifold leak, only deeper and less metallic sounding. Check around the air pump and those valves as well.

I'm only guessing here. You didn't mention how the truck was running after the sound started, so I'm assuming there was no change in performance. Mine did pretty much the same thing.

 

[shedevil]

yeah it runs the same,just the loud rapping.it is coming from the passenger side.i think i know what hard line youre talking about.theres the small gasket where it connects to the manifold? it didnt look badly rusted when i changed the gaskets last year but im hoping its the problem, or close