We're rebuilding the 4.0L engine in this 2005 Jeep Rubicon Unlimited. We added new JBA headers for better exhaust flow, an Airraid throttle body spacer, and a cold air intake setup from Airaid all ...

The famous 4.0-liter inline six motor in the Jeep lineup may be out of the offer for years, but its legend lives on. This is what a teardown and rebuild looks ...

Jeep's 1980s era 2.5-liter four-cylinder engine didn't have a ton of power behind it, but it was incredibly reliable, something it's still known for today.

Getting 400 HP Out of a 4.0-Liter Straight-Six Jeep Engine Requires a Ton of Work Especially if you're not using forced induction. By Brian Silvestro Published: Sep 21, 2020 12:52 PM EDT ...

If you've been around for nearly two decades like this piece of machinery, there's going to be good and bad years. Learn more about the Jeep 4.0L engine here.