What are common things to go bad on motor
 

Was just wondering for preventative maintenance what are some of the common things that need fixing or replaced on the 4.0 motor?

If your not careful when changing your oil filter one common thing to break is the oil pressure sending unit. Its right next to the oil filter. Ive been there done that on a couple different 4.0s now!

I just changed mine so hope that dont happen

Water pumps, hoses, valve cover gasket, oil filter adaptor O ring, fan clutch, idler pulleys, thermostat, distributor cap and rotor, plug wires, spark plugs, CCV elbow are just some of the things that should be checked or replaced.

How do you replace ccv elbow were is it

Don't let the engine get too hot, especially if its an I6 between 99 and 02, they have bad heads. The heads end up cracking and either need to be replaced ($700) or the whole engine might need to ($$$).

It is the elbow at the rear of the valve cover. If you're lucky you just pry it out of the grommet, but they almost always break because they get so brittle from the engine heat. Always use a new grommet when you replace the crankcase breather and CCV. When you replace the valve cover gasket on a ZJ with a 4.0 you have to remove the CCV in order to get the cover up high enough to clear the rockers. If you can't get it out, just break it off and once you get the valve cover off you can remove the baffle and pull the CCV through.

Thank you everyone has been so hopeful my next thing is my fuel pump relay I went to several stores they gave me the big square one but mine is the small micro lookin one none of part store can find the part number