Hey all im new to the forums, been a lurker for a while tho. I just got a '04 4x4 4.0 and the motor locked up and died, I am looking for a new engine to throw in there, I have a mechanic friend who will do it for $500. My question is what do you think would be the best size/type for the price to do a swap. I just bought the truck and I'm not trying to spend a huge amount, I'd like to stay under $2k...

 

Welcome to the Forum

You have a 4.0l SOHC engine in an '04 Ranger
Only engine swap available without changing computer, wiring, and transmission is another 4.0l SOHC engine

You will want an '05-'12 4.0l SOHC engine
1997 to 2004 could have bad timing chain parts, which could have been your problem, but that generally doesn't seize the engine, overheating and spun main bearings does.
If you can get a good deal on an '04 or older engine then changing timing chain parts will make it same as '05 or newer, parts are not too expensive, but engine has to be out to do this fix


4.0l SOHC were used in these vehicles:
2001–2012 Ford Ranger
2001–2010 Mazda B4000
1997–2010 Ford Explorer/Mercury Mountaineer
2005–2010 Ford Mustang

If engine is not from a Ranger then you may have to swap upper and lower intakes, not a big deal at all
Things to change when engine is out
Knock sensor(under intake), new one always
Rear main seal, any engine swap
Thermostat housing, these cracked and leaked on the 4.0l SOHC

And check with local machine shops to get a price on full or partial rebuild of your current engine, you will need to diagnose it first, "locked up and died" won't help

 

Thanks a million for the detailed reply, I really appreciate it!
I had it for about a month, only drove it less than a dozen times, the final time I tried to start it it wouldn't turn over, after trying a few times the engine seemed to lock up. Had it checked out at the garage and the mechanic said he tried to manually turn it with a prybar and it was totally locked, and I must've thrown a rod or bearing...
I will deffinitly start looking for those engines specifically, I'm not too mechanically inclined so I'm learning as I go! I hear a rebuilt engine is the way to go but it is more pricey...I'll have to weigh the pros and cons, thanks again!

 

You would have known if you "threw a rod" makes a pretty bad noise

Spun Main bearing wouldn't but you would have seen no oil pressure or jumping oil pressure gauge while driving the last time.
And engine should have just died before turning it off.

But you say it did turn over at first and "then seemed to lock up", so not a spun main bearing.
A spun main bearing "welds" itself to crank and block from overheating because oil was cut off, i.e. low oil level in engine or failed oil pump, but it can only happen with HEAT and once it happens engine can not turn so slows down and dies.
And thrown rod engine will turn just won't turn all the way around in either direction, and a rod is thrown while engine is running, can't happen while starting

I would pull out all the spark plugs first, could have leaking injector, or coolant, that hydro locked engine
See if engine can be rotated by starter motor, after spark plugs are out, could be starter motor died
Then see if you can manually turn crank in BOTH directions

From your description is seems like a little more time should be invested in this engine before discarding it for another
So there were no "noises" prior to the last time engine was shut off?
No ratting chains?
No sluggishness in power?