Joined
·
246 Posts
I went through a similar problem with my 5.3L V8 in my 2004 Silverado. GM used a company called Castech to make the aluminum heads on some of their engines. At 119K miles I noticed coolant loss with no leak & also a collapsed lifter. Pulled the valve covers and heads were full of coolant and oil pudding. I ended up replacing the heads and left the bottom end alone. Google GM Castech head problem. You think GM would learn....