[arpad_m]

Originally Posted by Jonnydz

So u think gm fixed the pump in the newer zl1s? I would love to hear your explanation supporting this

Here's some statistical evidence. GM changed the oil pump part number several times, and their last change (to part number 12686434) corresponds to the drastic drop in failures reported through this forum.

Now obviously this isn't a fully representative survey, but it's most likely relevant.

Note also that failures weren't completely eliminated, which was highlighted by Katech in another thread; GM improved the design but didn't completely address the root cause (as usual). However, Katech's billet steel replacement seems to be bulletproof.