you can run a very long time with piston slap. I had it on a Dodge 2.2; and a Chevy 2.0. there are also solutions other than a new engine; it can be repaired; I had a friend who got his fixed under the Chrysler 7/70 warranty - even though it was certainly his own fault. (hardly ever changed oil and ran it low. the oil I drained out looked like a milkshake)
On my Cavalier, the Chevy dealer fixed it even though I was out of warranty at 45k. they were very impressed with how clean the engine was inside. they tried rebuilding it; but it was even worse after; so I ended up with a new short block. Jeep 4.0's are well known for piston slap. anyway, multiple sources will say it's more of an annoyance than a problem.
On my Cavalier, the Chevy dealer fixed it even though I was out of warranty at 45k. they were very impressed with how clean the engine was inside. they tried rebuilding it; but it was even worse after; so I ended up with a new short block. Jeep 4.0's are well known for piston slap. anyway, multiple sources will say it's more of an annoyance than a problem.