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stock replacement crate engine 4.0

CAJJ93XJ

NAXJA Forum User
NAXJA Member
Location
Roseville, CA
I keep throwing money at my engine and **** just keeps going wrong. plus there is visible layers of thick gunk built up all inside the block and I'm convinced it's the cause behind my overheating issues. I've thrown well over a grand at it and parts keep breaking. maybe it's a lemon 4.0? don't care. at this point it looks like in the long run it will be cheaper to just swap it


I'd rather just get a crate engine. I'm not interested in a stroker I just want a reliable, predictable, long lasting, clean 4.0
I read that NAPA auto parts has one (but their site is being stupid). where is the best place to get an engine for just over $1000?
thoughts and suggestions?
 
4 Wheel Parts has them but they are around $1700. Looks like Autozone's are $1500. For that much I'd pull the existing engine and have it worked over by your local machine shop.
 
The gunk can be slowly cleaned up, that shouldn't really determine whether or not you pull a working motor. Just don't use a super harsh cleaner (like sea foam) the first time around. I use sea foam every now and again just before its time for an oil change, had the pan off about 6 months ago doing a rms and no gunk to report in a 92 with 180k.

Go get a couple filters ($3.99) and Google a remedy you would feel comfortable with and change the filter every couple hundred miles and then do an oil change.

But if your dead set on a new motor I agree with pulling it and having it gone over by a shop before dropping $1500-$1700 on a motor. I have also "heard" that some of those autozone/Napa motors have problems from the get go.
 
4 Wheel Parts has them but they are around $1700. Looks like Autozone's are $1500. For that much I'd pull the existing engine and have it worked over by your local machine shop.

the damn thing keeps giving me crap. I kind of want a fresh start. everything around the engine has been replaced already.. including my heater core. this engine keeps leaving me stranded and it's getting pricey
 
The gunk can be slowly cleaned up, that shouldn't really determine whether or not you pull a working motor. Just don't use a super harsh cleaner (like sea foam) the first time around. I use sea foam every now and again just before its time for an oil change, had the pan off about 6 months ago doing a rms and no gunk to report in a 92 with 180k.

I will talk to my "trusted " local mechanics and have them check out the engine. if they can diagnose my overheating problem and I can clean out the gunk I'll probably keep it then. I'm running out of parts to replace anyway. I'm just an impulse buyer when things go wrong
 
What year is it, and what is the entire history, story on the over heating issue, what all have you tried and done so far. IS it all stock, if not what mods does it have?
 
^^good point I probably should have included that info

1993 4.0 granny driven off the lot. she passed and it sat for 2 years before they sold it to me. they fired it up with a new battery and I bought it. the engine seems great just everything around it fails

replaced:
radiator (yes it was burped properly)
water pump
zj fan clutch
tstat like 3 times. now I run open because I over heat with a tstat
heater control valve
heater core!
and recently my distributor exploded. so distrib, cap, and wires replaced

probably more but I can't remember. if my heater core looked like this, I'm afraid of what's inside the block

123.jpg


I thought I did a pretty thorough job of getting everything replaced. which leads me to believe that the inside of the engine has some blockage... or something. I'm out of ideas. you can see why I'd be frustrated enough to just go buy a new engine. all this work and still consistent break downs, overheating, and problems

143.jpg
 
is your water pump reverse rotation?

If not that could be the cause of all of it, and if running with a t-stat is a sure fire way to make it overheat I'd pull the pump and check it's impeller. It should be stamped with an R.
 
If your block is like mine, you will never, NEVER get all of that crap out. I took out my water pump and found layer of that red rusty mud substances caked all over the block. I finally rebuilt a donor motor and tossed the other one to the birds. It got to the point where I was literally flushing it 5 times a week trying to keep it from overheating. Every time, the coolant came out brown, thick, and muddy.

I had a thread when I finally pulled the old motor apart. Lemme dig it up.

Here we go. Check out all the red crap in the coolant passages.
http://naxja.org/forum/showthread.php?t=1067322
 
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is your water pump reverse rotation?

If not that could be the cause of all of it, and if running with a t-stat is a sure fire way to make it overheat I'd pull the pump and check it's impeller. It should be stamped with an R.

I have never heard of this. check the impeller for an R got it.
I got the pump from O'reilly and we know how reliable and competent those employees are...

I had a thread when I finally pulled the old motor apart. Lemme dig it up.

Here we go. Check out all the red crap in the coolant passages.
http://naxja.org/forum/showthread.php?t=1067322

mine is more of a brown muddy build up. it looks pretty bad. I'll try running an engine cleaner as well and see what happens
 
I'll blatantly steal this guys explanation as it's better than mine:

Look at the history of the 4.0. It was born as a 4.2 - same block, same pump casting, same everything. The 4.2 had a Vee belt.

When they went to 4.0 no change - still the same pump.

When they went to a Serp belt, the way it's strung made the pump turn the opposite direction. No other changes, except now the impeller turned the other way, so the vanes had to be reversed so the water would flow the right way (goes in the top of the radiator and out the bottom.)
On those the OEM pumps had a stamp or embossment - either a R or REV was cast into to housing in the front to identify that it turns the other way. Also the impellers had an "R" stamped on it.

After a few years the serp belt type became the standard, they stopped putting the R or REV on new ones.
When you get a rebuilt most of them are of the older castings - REV or R can be on them. But rebuilders don't always go by that mark.

That leads to massive confusion - the only way to be sure you get the right one is to compare it with the one you took off. Don't go by the REV or R - it may be wrong.
Look closely at the impeller vanes - they should point the same way as your old one you took off. COMPARE THEM!
The castings are totally identical, just the impeller is different.

How do you tell once you put it on? If it overheats fast, and the radiator is not plugged, suspect the pump. Remove the thermostat and put the housing back on. Disconnect the upper hose from the top of the radiator.
Make sure it's full of water.

Start the engine - water should stream out of the top hose like a firehose - if it's correct.
If it's the wrong one, at best it may dribble a bit out of the hose itself, but the water will flow out of the radiator snout - backwards from what it should be.
That test is only valid if the thermostat is removed.

Don't assume the parts house will give you the right one - it may cost you an engine.
Just LOOK!
http://www.wranglerforum.com/f5/2000-4-0-water-pump-47163.html
 
A lot of us have done horrible, horrible things to our 4.0's and they keep working. It's an engine with a reputation for reliability for a reason. Don't drop the cash on a rebuilt engine with no history when you can find a used one from one of the members here for a fraction of that price and know exactly where it's been and how it's been taken care of.

If you're dead set on changing it, find yourself one with 80-100k on it and save yourself some cash.
 
this one had 118k on it when I bought it. thought I was safe right? wrong..

Did you read my whole comment? I didn't say run down to the pull a part and yank one. I said find one from someone you know or someone you know here and get one that you know its history on.

Mileage doesn't mean anything if you don't know how it was taken care of. Not that I don't think your engine is worth fixing, because it is. But I'd take a used engine from one of our Cali folks over one rebuilt in a factory with chinese parts anyday and I don't even like the guys from Cali. :laugh3:
 
I don't even like the guys from Cali. :laugh3:

join the club

alright I'm waiting to hear back from the shop on my repairs. gonna go pick up the heep, wheel the piss out of it, then check that water pump R deal. if that isn't the problem, what should I look at next? should I just pay the shop to figure it out for me if this doenst work? open tstat in the winter makes my jeep not happy
 
Re-read your original post. The answer lies within.

I keep throwing money at my engine and **** just keeps going wrong. plus there is visible layers of thick gunk built up all inside the block and I'm convinced it's the cause behind my overheating issues. I've thrown well over a grand at it and parts keep breaking. maybe it's a lemon 4.0? don't care. at this point it looks like in the long run it will be cheaper to just swap it
 
$1k crate engines don't exist. By the time you get done with the engine options that are out there, you'll likely have $2k into them.

If you're dead set on it, then have at it. Or get multiple quotes on what a rebuild will cost you. And also you should never rule out a salvage yard swap out. For vehicles as old as ours, it sometimes is the most economically wise solution. With a new engine, you will almost always have more into the vehicle than it's worth. That doesn't remove sentimental value, it is just pure economics. I've only been burned one time on a JY engine in 38 years.
 
When you say"keeps breaking down and leaving me stranded", what does the rig do when it leaves you stranded?

Does it get so hot that it stalls out?

Does it run well until it craps out on you?

I guess my question is,does it run ok except for the over heating issue?

If your going to get a new mill anyway I would run the piss out of this motor and get to know the 4.0's good and bad points.

Put a dealer t-stat 195* in it and fill the radiator with coolant and then pull top hose and fill the motor up with the coolant temp. sensor at the back of the head removed to let out air.

Good luck
 
you will almost always have more into the vehicle than it's worth.

I'm already way past that sadly. so I figured hell might as well go balls to the wall with this build. thanks for the advice. a crate engine was just an impulse thought I'm glad I came here for you guys to talk me out of it

When you say"keeps breaking down and leaving me stranded", what does the rig do when it leaves you stranded?

Does it run well until it craps out on you?

Put a dealer t-stat 195* in it and fill the radiator with coolant and then pull top hose and fill the motor up with the coolant temp. sensor at the back of the head removed to let out air.

Good luck

it runs fine. but then suddenly a random part will just explode. my distributor bracket literally sheared off and popped out. just driving. and this has been consistently happening ever since I got it. the heat is fine off road (on road it runs at 105*F because of the air flow). it heats up to 210 off road and stays there (no thermostat). it'll heat up a bit if I'm struggling on an obstacle for too long. but as soon as I get some air flowing through it, it cools down right quick

the problem is with the tstat. I put in a dealer 195* tstat (with the bleed hole) and flushed and burped it properly. but I've never heard of removing the sensor at the back of the head to let the air out. I guess I could try that next

with the tstat in, it over heats AT IDLE. driving around keeps it just over 210 but off road it's miserable and it over heats
 
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It sounds like 90% of the xj's out there 80% of the time!

My 89 ran at 210 and above since the first day I drove it off the lot.

I went wheeling in the Mojave the first weekend I had it and idled around in 4lo and to my surprise that gauge would stay upp at 212* and the aux. fan would come on.

The rig had less than 1000 miles on it so I knew it was operating as designed.

These trucks run at the upper temps and seem to like it.

My personal experience with overheating was a hole carved in the radiator from my fan clutch that would pump the engine coolant completely dry and peg the temp gauge and the motor would die.

Continued to fill it back up (after letting it cool) and drive down Watt ave. towards home until gauge pegged and motor quit.

This happened 7 times in an hours time. I thought for sure the old rig was going to crack the block or atleast warp the head.

Long story short finally got home that day. Went to P-N Pull for a radiator and never looked back. That was in July of 2008 and about 140,000 miles ago.

Don't ask me why this mill stayed together and doesn't burn a lick of oil!:woohoo:
 
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