4.0 Death

[bootlegger]

Engine went to 260 and blew a hose in my xj.Now she won't stay runnin. I'm assuming head gasket went.203k on the clock.Do I fix, replace or repower? Tight budget. I like little 4 cyl. diesels though......?

[monkeystrong]

Depends.. if its the gasket, then replace and keep on truck'n. if its the head itself, then I would start looking for options.

[WrenchMonkey]

Tight budgets and diesel conversions do not go together...

Fixing what you have is almost always cheaper. Even if you have to replace the whole engine, a bolt-in replacement is going to be faster, easier and cheaper.

[bootlegger]

I guess I'll get the head off and go from there.I'm just thinking it's probably cracked.
BTW i was just reading that there's a 4.0 poweresd vehicle in the current Dakar rally.

[humpy]

Put a tstat and new hose on and try it first... It's likely not runnin because of lack of coolant I noticed both if our 4.0 engines don't run right without coolant system sealed up and coolant in them ..., or u may have frozen it and junked it ... Is that possible?

[bootlegger]

Something is freezing up.The crank pulley is smoking the belt.Accys are barely turning. I'm thinking water pump or power steering.

[WrenchMonkey]

Something is freezing up.The crank pulley is smoking the belt.Accys are barely turning. I'm thinking water pump or power steering.

Oh, well if it's just an accessory, you're definitely better off fixing. Pull the serp belt, and see what won't turn by hand. Easy.

Unless you were looking for an excuse to bump up to a V8. I don't mean to discourage that!

[GPER]

I guess I'll get the head off and go from there.I'm just thinking it's probably cracked.
BTW i was just reading that there's a 4.0 poweresd vehicle in the current Dakar rally.

There are two Jeeps in the Dakar and the top one was in 94th spot as of yesterday.

[bootlegger]

After removing the belt , everything turns freely!!??
Good news is the oil looks fine and it drove back to the barn ok.I think i will change t stat, put a new hose and belt on ,fill up on critter killer and hope for the best.

[tjrider]

My tj over heated at big rock last summer cause my electric fan motor gave up. It ran like **** for a while after I cooled it down, then was fine. They have to relearn after over heating

[WrenchMonkey]

They have to relearn after over heating

Depends on the year. Pre-91 was Renix, and stone simple.

Overheated mine at DTOR after filling the radiator with mud. Cleaned it out and went on my merry way. No learning required...

[bootlegger]

Update: Today I put a new t-stat, water pump, upper hose and distilled water/ prestone mix and she seems fine.What a relief!!! And right before the snow started to fly.
It ran for way too long with the gauge pegged at 260 before I could get it off the road.So I was sure that it was going to be damaging.
BTW I'm a huge believer in Motorkote and I run it in all my vehicles.

[WrenchMonkey]

Good deal!

For what it's worth, I'm a huge believer in the 4-0. Awful hard to kill the bastards!

[underpowered]

Good deal!

For what it's worth, I'm a huge believer in the 4-0. Awful hard to kill the bastards!

x2.

the 4.0 in my old 95 ZJ has had the temp gauge buried multiple times, ran at the rev limiter for extended periods of time, been on Fire, and just generally beat on and still fires up and runs like a champ through all the abuse.