md21722

2000-2001 models had coil packs instead of distributor and also a new intake manifold. I don't remember what year the new intake was phased in. So if you go early, you have to deal with those issues. If you get a used TUPY you will have no worries about compatibility but depending on the condition you get it, you may need to transfer parts from your old head and will need machine work. There are also places like National Cylinder Head or Clearwater Cylinder Head that sell an improved casting that is ready to bolt on. Many here are running Clearwater heads with no problems.

Firestorm500

I haven't had good luck with used heads.

I think I would go with one of the ones the previous poster suggested.

I would only want to do this once, because of the aggravation factor.

Parsnip

Coils can be mounted easily, just make a bracket off the vc or oil pan. The intake was for 99+ Cherokee, and only fits a 99+ head. Everything else (so long as its a 96+ xj) is bolt on.

bigbadon

I would not categorize that as preventative maintenance but if it makes you feel better buy a head and put it on a shelf. I have never believed in replacing something that is working well. Not all 0331 heads crack and even the tupy is not failsafe. The 0331 was cast in a foundry that used a large number of molds so I think it is luck-of-the-draw. Number 4&5 exhaust ports are simonized so this creates a hot spot on the head. The tupy added more iron in that area. Still there have been many 0331 heads that have made it to 300k.

madmanmarty

OP. small easy steps first. then move on to the major items to fix.
always remember, you can fix anything. dont sell your jeep. youll be sorry you did. get some help and start wrenching.

Wojtas

Alright, well since I know that it is only rust in my coolant and not oil, I still cannot determine why I keep overheating. What would be causing this, and why did the genius before me think that removing one of the radiator fans would be a good idea? I just wanna take this thing wheelin' without sending the temp gauge into the red ):

Would a poop thermostat have any effect on overheating? Because when I got this duracrap thermostat while running dexcool the jeep never got up to running temp, always stayed at 160 and took forever to heat up. And now since I flushed everything it keeps running too hot like at 210 even when it just idles in the driveway

Epk5150

210 is what I run at on a daily basis. I have replaced everything in my cooling system with the exception of the radiator. I have a duracrap coolant temp sensor so maybe it is just reading a little high. Since I replaced everything I haven't seen it get above 220. I think these Jeeps just naturally run hotter. I also wired a switch to the electric fan because its not turning on automatically and its easier than chasing wires/fuses/amps trying to figure out the problem. Believe it or not but the radiator cap can cause issues as well. Mine was a little gunked up causing it to not function properly, replaced it and now my coolant is bright green and engine runs at a constant temperature.

Epk5150

I know you are young and a student but if you have a hundred dollars I would go ahead and replace everything. Its nice to know that everything in your cooling system is new. I bought everything from rockauto.com for less than a hundred including water pump, thermostat, upper and lower hoses, radiator cap, fan clutch, and the water pump hard line. Just make sure its completely clean in there before installing the new stuff. I know some people will disagree with me for throwing parts at it but for less than a hundred dollars its a great peace of mind.

SteveMongr

^ I agree. Our 4.0 blocks are known for the gunk that accumulates from lack of maintenance or whatever. This crud easily clogs passages in the radiator and can plug passages in the block. Also eats at the blades on water pump.
Replacing the entire cooling system and washing out crud from block and heater core can do wonders for steady temps in most all conditions.

Wojtas

Ive already replaces all of this, new water pump, thermostat, radiator, all hoses (heater and radiator) even powerwashed the overflow bottle to get every last piece of gunk out

Epk5150

Well then I wouldn't worry about it. If its all new and you are running 210 constantly without getting near the red than you will be fine. It could be a gage issue and no longer a cooling issue. See if someone has an infrared temp gun to get a better reading of block temperatures.

Correct me if I am wrong but you are no longer having thick rusty coolant and you are just worried about temps now right?

RTorrez1

Don't worry if it's running at 210. 210 is the normal operating temp for our 4.0

HappyPappy

Hear is a hint if you use cascade or anything else. I used strait vinegar in mine for three days, started see leaks at all the hoses Had to flush ity, all kinds of crap came out, but it still runs hot. Most 4.0 accumulate crude at the back of the block around that plug in the back of the block. Right now I have two cups of Oxy Clean in it, water still looks like brown crap. I,m going to flush it in the morning and see what happens there. I may have a weak water pump. That will be my next change. I installed everything new last fall, rad, wp.thermostat and housing, fan clutch. It's a pita, but you almost have to live with it, look at it this way, You have a HOT ROD!!!!!!

If mine ever straightens out I'll let you know.

Parsnip

Key thing I think should be pointed out here-210 is normal, 216 is when the e fan should kick on to assist. If it's nudging over the third tick you have a small problem, if it hovers around 210 your fine

Wojtas

Hey guys, just an update on the xj.
I have determined that a new head is something that I will do once I get the money, and have determined that my loss of oil was due to the thin nature of the 10w-40 and it was leaking from the oil pan gasket. The brown stuff in the coolant I have also determined is only rust in the system.

So what I did to solve the overheating.
I went to autozone and picked up a 13 inch electric radiator fan, cut off the stock plug that comes on it and soldered it to the existing electeic radiator fan wiring. Kicks on at around 215 and cools the jeep down real quick. No more overheating episodes!

Thank you for all of your help guys, and like ive said many times before, without this forum my jeep would surely be in the junkyard by now