Zach2610

I need to get my 1994 running better. It ticks bad and i have alot of smoke from the exhaust so i think its pretty worn out. I have 145k miles on it, who has the best rebuilt engines or should. i look for a used one? Thanks guys

EastBeast

Maybe it just needs a tune up? 145k isn't really that many miles for a 4.0 if its even been halfway maintained.

Chickenfloss

What color is the smoke. As far as rebuilt, if you want to invest some money you can get a jasper for about $3,000 and comes with 3 year/100,000 mile warranty. If you are getting a mechanic to put it in for you expect total costs of around 5 grand.

Bustedback

145K miles? It's not even broke in yet.

tjwalker

Run a compression test. Both dry and wet. That is a good "snapshot in time" of the internal condition of the engine.

The compression spec for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

The compression test tells a LOT. Anything less is guesswork.

1991Jeep_Man

Find a mechanic friend, tear it down, and rebuild it as a stroker.


OR


Do the ultra cool thing I'm about to do or that many other have done and swap in a V8 lol.

But in regards to your thread and giving a more "instant fix" issue, take the steps above and find out the true condition of your engine. Blue smoke is bad (serious oil burning). Is it losing coolant? Rod knock? The tick could very well be a gummed up lister. Run some MMO through it or use that Engine Flush next oil change just before you drain the oil. Any check engine codes? Also, remember, and any forum member here will agree, the 4.0 likes to make its presence known. It is NOT a quiet engine... even when perfectly maintained and operational lol.

Zach2610

Yea its runnin a little hot and drippin alot of oil. I put in a really nice radiator to try to fix the heat issue and it helped......but now its gettin too hot again. I see all these cherokees gettin 200k but i dont see how. It overheats when i try pullin a empty 14' trailer. I love the jeep but this is the third my family has owned and i havent seen one yet that was dependable. I hope i can get this thing goin. My dad says its the lifters that r tickin so bad and that it needs a head job.....idk wat to do lol Thanks 4 The replies

1991Jeep_Man

A lot of guys on here have XJ's with many miles. The most on the net recorded is over 600K. I am at 207K, no issues. And mine is barely broken in.

It's all in maintenance. As for overheating, the radiator is only part of the equation. Is the t-stat opening up? Is the water pump working? Fan clutch good? Hoses collapsed?

Also, oil leaks are common on the 4.0 in 4 spots: front main seal, rear main seal, valve cover, and oil filter adapter. All are fairly easy to replace.

Lifters on the 4.0 usually don't drastically die unless they are oil deprived. But they also gum up and make on hell of a chatter. Try running the Engine Flush through it, then add some MMO to your crankcase.

In regards to the lifters also, is your oil pressure within spec?

Edit: I'm gonna be honest here and put it out plain and simple; the XJ 4.0 is damn near bomb proof. Guys have overheated them into the red multiple times, no lasting issues. Ran them with barely any oil in them for various distances, no lasting issues. They will use basically any type of oil (some guys use 0w20, 5w30, 10w30, 10w40, and some like me use 5w40). You could probably fire bullets at the engine, and it'd still keep going. If this 4.0 is dead or dying, it likely isn't because of factory defect. And also the fact that you said your family had 3 XJ's and none were dependable makes me think maybe things weren't kept up with. If they were, then I'll admit my wrong saying. Either that, or if ya'll are buying used, then the previous owners need a lesson in preventative maintenance.

Zach2610

Idk how would i go about checkin that

Zach2610

And yea its one of those deals where those we had were good and used by the time they made it here, since iv had this one its been maintained but it had 100k when i bought it

Zach2610

And thanks for the tips ill look into that stuff u mentioned

1991Jeep_Man

I hope I didn't come across as rude, and if I did, I apologize.

The BEST way to check cooling system components is to first verify your temp gauge is working properly with an infrared gun, but we all don't own said gadget, so let's assume your gauge is correct (like I always do [pray] mine is).

Start with the basics. Run the truck, let it warm up, and at around 197 degrees (or just before the 210 mark), the upper radiator hose should be stiff and hot. This means coolant is flowing, which means the t-stat is opening.

CHeck the lower hose to see if it is crimped/bent/collapsed. Visual inspection is fine.

Water pump. First see if there is a stream of coolant coming from the weep hole under the pump body. You'll see a lovely green stream of sorts. That's a sign of a bad water pump. Also, a whining noise is an indicator of a bad pump (personal experience with this one). If your t-stat is working but pump is not, then the upper hose will get hot, but not be stiff.

To locate your oil leak, first check around the areas mentioned above. The front main seal and oil filter adapter will be obvious (oil on/around the adapter; oil dripping from the front of the engine). The rear main and valve cover can look the same. Feel the back of the cylinder head. If there is fresh oil, thats your valve cover leaking. If the head is dry, but there is oil leaking from the back of the engine, that's the rear main.

Oil pressure is self explainatory. No less than 13 psi hot idle, and over 35-75psi over 1600 rpms. Low oil pressure will cause an assortment of noises, including lifter tick.

ALSO, and I can't believe I forgot this, your 'lifter tick' may not be lifter tick. Ever heard of the infamous 4.0 exhaust manifold crack? When it cracks in just the right spot and way, IT IS LOUD. When mine went (check my how to in the XJ how-to section), I thought for sure a lifter had grenaded or a valve dropped or something. Check to see if your manifold is cracked (usually at the collector and/or the middle or front/rear runners).

Whew, ok. I'm done lol. Check those, and get back with us. I'm confident your XJ's engine can be brought back to full health. We'll help you.

Zach2610

Thanks a ton

fishtaconc

Couldn't agree with this statement more. My '91 had 295K when I sold it, still running today(5yrs later). If you have had an unreliable 4.0 it must have been neglected, this engine lasts a long time even with marginal maintenance probably one of the most reliable engines along with the Toyota 22R. Follow 1991's, suggestions for checking the cooling system, etc. FWIW to replace the main cooling system components, will only run you ~$250, cheap insurance. I will add just for grins do a compression test.

Zach2610

Hey what is "mmo" ?