'01 with collapsed lifter?

I have a knocking in my engine when I start my blazer. Its sounds different each time I start it. Sometimes it doesn't last very long. It sounds like it could be a collapsed lifter but I'm not sure. Any suggestions or remedies?

Have you ever had leaky intake gaskets? Have the gaskets ever been replaced? If they have whats the milage sinnce replacement? Is the noise only at start-up? Are you loosing any coolant? When the intake gasket begins to leak internally, coolant can make its way into the lifter causing eventual damage to it. Usually this can be seen with a noisy lifter, more upon start up, and a low coolant level.