Whether you just bought a lawn-ornament Jeep that hasn't run in years or you've neglected one of your own projects, your motor will need a little CPR and mouth-to-mouth to bring it back to life without damage.
Engines are complicated assemblies with many precisely-machined parts that require proper lubrication. But they are also extremely easy to make run. Get fuel and spark to happen at the right time and you've got a running engine.
However, an engine that sits for more than six months can be a problem. Fluids separate, metal oxidizes, and seals dry up. There are a few steps required to provide spark and clean fuel, and also some work to make sure that no problems have developed during hibernation.
Almost no one, including us, plans on their Jeep sitting ignored for years. So usually the engine isn't prepped to avoid damage and problems during storage. Here's what you should do before starting an engine that has been sitting for awhile, as well as some troubleshooting help in case it doesn't fire right up.
It's Alive! Hopefully, you followed the steps outlined here and were rewarded with an engine that fired up and is now running. Do yourself a favor, and don't close the hood and hit the highway just yet. Give the entire vehicle a thorough inspection while the engine is running to check for leaks and problems. Here are a few often overlooked things to check:
•Look for coolant leaks from hoses •Check cooling hoses for spongyness •Inspect the weep holes on the water pump and engine-mounted fuel pump; replace the parts if they are weeping •Check the sides and front of the engine to see if any of the freeze plugs are seeping •Look under the Jeep at the bellhousing - there are freeze plugs at the rear of the block, and oil may leak from the rear-main seal •Check for fuel leaks along the entire path of fuel system •Is it overheating because of a clogged radiator? •Look for oil leaks from gaskets and oil fittings •Make sure the electric fan comes on when it should or is the mechanical fan and clutch operational? •Is there plenty of power steering, tranny, and transfer case fluid?