DIY Jeep YJ 4.0L Engine Bay OVERHAUL + Tune-Up

Hey folks, in this video, I’m doing a DIY engine bay overhaul and full tune-up on my 1991 Jeep Wrangler 4.0L YJ. The legendary Jeep 4.0L inline-six is known for reliability, but after years of use it needed some serious love. I’ll walk through cleaning up the engine bay, replacing worn components, and giving this classic YJ the tune-up it deserves. If you’re looking for a Jeep YJ tune up guide or want to see how to refresh the Jeep 4.0L engine, this video will help you get it done at home with basic tools and some patience. Don’t forget to like, comment, and subscribe for more Jeep YJ projects, builds, and tutorials here at No Guarantees Garage! 🔧 PARTS & TOOLS USED: Can of black paint: https://amzn.to/4oLh8bq Can of aluminium paint: https://amzn.to/4oRjs0F Radiator cap: https://amzn.to/4hEip1G Valve cover gasket: https://amzn.to/4ozTr6c Upper radiator hose: https://amzn.to/49Bgl8I Lower radiator hose: https://amzn.to/3JIg9tI Thermostat: https://amzn.to/47pbqX3 Thermostat housing: https://amzn.to/3LmoaVQ Wire loom: https://amzn.to/43TzNd7 Wire tape: https://amzn.to/49xOOF9 👕 MY MERCH: Check out my shirts, stickers, and diagnostic manuals to help support the channel! www.noguaranteesgarage.com ⚠️ DISCLOSURE: Some of the links above are affiliate links, which means I earn a small commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Thanks for supporting the channel and helping me make more DIY Jeep content! Chapters: 0:00 Introduction 0:27 Removing all the Easy Stuff 1:49 Battling the Thermostat Housing 2:55 Finishing Removal 3:18 Cleaning Everything 3:54 Removing the Valve Cover 5:11 Cleaning Up the Valve Cover 5:39 Painting the Engine and Bay 6:04 Assembling the Valve Cover 8:18 Alternator is Bad 8:55 Installing Valve Cover 9:42 Heater Hose Removal 10:24 Spark Plug Gapping + Install 11:51 Distributor Gasket Replacement 14:33 Cap and Rotor Replacement 15:46 Coil and Plug Wire Replacement 16:01 Thermostat, Housing, and Gasket 17:42 Heater Hose Install 17:49 Radiator Hose Install 19:17 Looming the Wiring 19:27 Oil Change 20:38 Fuel Filter 21:19 Alternator Replacement 21:40 Coolant Temp Sensor 22:17 Air Box and Filter 22:58 Final Product 23:25 How Much Did It Cost? 25:45 Outro