i have a 1997 jeep Cherokee sport with a 258 4.0 motor. the vehicle has 165,000 miles and im wondering if i should have the motor rebuilt or not. can anyone help me out and maybe give me some advice on choosing a shop to take it too.
Expect AT LEAST 200k miles from a 4.0 that is even remotely cared for. Many hit 300k, and I know of at least one that has gone over 600k. For many of your questions, familiarize yourself with JeepForum and/or Google. The XJ has been around a long time; most things have already been covered quite well.
how far will these motors go before they need rebuilding?
the 4.0L is simply one of (if not "the") most bulletproof engine ever made, Ive been through 2 XJs, a WJ, and a ZJ- all 4.0s. NEVER had any issues with engine itself, the body, suspension, and/ or transmissions always fall apart long before the 4.0L does.
dont even think of rebuilding the motor unless its knocking or has low compression, low oil pressure due to worn bearing/ seals... even then, it should keep running for a while.
98 XJ- 4.0L, NP231, AW4, chryco 8.25, 4.5" mid arm 3-link, 285/75 Herc terra tracs on moabs, V8 ZJ tie rod, fabbed bumpers...