6.7 Have a bad knock took it in and checked and found scored cylinder walls numbers on #6 28000 miles on motor Ram can`t warranty because I used napa air filter not a stock from Chrysler what do you think?

 

Depends on where you are located. If in the States and the filter meets OE specs, they have to warranty it. The magnussen-moss warranty act applies. Anywhere else you might be out of luck. If they won't budge, it might benefit to contact a lawyer. 28k isn't anything and it sounds as the filter is being used as an excuse.

 

Check the intake tube right by the filter - if there's a bunch of dust in it, they're going to deny your claim due to 'dusting' caused by lack of adequate filtration.

If the intake is clean there, it's definitely not caused by the air filter. OE spec replacement filters typically aren't a problem.

Do make sure you're using decent oil filters though, if they've got neoprene in them, it will dissolve and plug fine oil passages, including your piston cooling oil squirters. That's definitely not something they'll cover under warranty. The Chrysler dealer I used to frequent had the TSB taped to their parts counter.