Message: I went outside today and started the truck (91 3.9l 4x4, 145,000 mi). Opened the hood and turned the valve a little then reved the engine. NO MORE RATTLE. I let the valve go and revved it, Plenty of rattle. Hmmm. So anybody have any service tips for the heat riser valve other than hitting it with penetrating oil?
Subject: Heat Riser Valve Rattle