Knocking noise coming from driverside valves

SHEEN20S

MEMBER
CHEVROLET SUBURBAN

I have a 1992 Chevy Suburban 2wd 5.7 with 206,000 miles on it. The truck has been sitting for a year and I just started driving it again. The engine sounded fine. Then 2 months later on a short trip I heard a low tap coming from the engine. I cut the car off and cut it back on and the tap became louder and when I put it in drive and proceeded to go it got louder and started to sound like a metal ball rolling around on acceleration. When it is idling it just knocks. I changed my oil and put an engine treatment in but it still sounds the same. When I put it in drive the knock goes away but as soon as I drive it does what I said up above. In neutral it sounds just as bad as it does in Park. I had no warning of this problem. What could it be? Help!

1 Reply

AACPLUS

MEMBER
60 POSTS

Take off the valve cover and make sure a rocker hasn't come off the pshrod, if they are all in place, start the engine and isolate the noise.
I have seen the rocker twisted sideways out of place and causing noise as well as rough performance, and also have seen the pushrod break in two, usually up by the top of the push rod. It may look intact until the rocker is loosened to inspect the push rod.
Also, if a push rod is plugged, it will not oil and cause noise.