mclasser

A buddy of mine has an 03 Max and he has a knock at idle when the car's warmed up. He's usually good about checking his oil level but he forgot to for the past few months and it was 1.5 qts low. He topped it off and after 100 miles, the knock's still there. We can't really tell where in the engine it's coming from exactly. Doesn't sound like a timing chain rattle. It's not too loud and goes away when accelerating. Could being 1.5 qts low have caused severe engine damage?

Turbonut

I'd say 1.5 qts low wouldn't cause the problem unless he's driving 100 mph for an extended period of time.
Is it a knock or just more conscious of valve train noise?
When at idle, check each cylinder by disconnecting the coil one by one to see if noise changes.