99 5.3l in my 70... good engine¿

[Bluechevy68]

Originally Posted by 67ChevyRedneck

The head problems were mostly with the 2001 model year engines.

The biggest problem with the 99-02 motors is piston slap. GM didn't quite get the piston/ring/wall clearance quite right, so on startup the pistons were "loose" (we're talking thousands of an inch) and until they heated up and expanded most of these motors experienced a "knocking" sound at start up that lasted anywhere from a few seconds to a minute (the sound was longer/worse in cold winter months). Mine started doing it around 80K and it has 155K on it now. Doesn't harm the engine. They fixed the issue around 01-02. If you rebuild this motor any kit you buy should have the revised parts. Also, if the oil wasn't changed regularly they could develop a lifter tick. The lifters have a tiny orifice and could become plugged.

Mine has the "knocking" also and once it warms up it goes away just like you said. I think the my engine is going to outlast the truck's body.