[No engine that has had regular oil changes (5,000-7,500 miles) will have sludge. ]
Sorry to say my engine has had oil changes every 3-5,000 for the life of the vehicle and now has sludge. And it has had tune ups as well - the car has been cared for - really.
Thanks for the other info though - they are fixing my engine and I have opted out of the settlement at the advice of the court appointed 3rd party, so that if I have any future problems after 8 yrs is up - I could still bring them to court if they do not fix it (as I do have sludge b4 warranty is up and proof of maintenance)