I have a 2000 Jeep Tj with the 4.0. I have had so many items replaced on this jeep but when the engine is stressed like the other day I was driving up some mountain roads I drive up all the time and the engine kept overheating. This engine has a new head (the old one was cracked), new thermostat, radiator, radiator cap, water pump and no coolant leaks. The only thing I can think of it has a check engine light for a 02 sensor I replaced with a ngk one and nothing changed. I’m so tired of this constant isssue of overheating.