Hello
I have a 2000 ford ranger 3.0 v6 with 235K miles on it. It has started a very loud and obvious rod knock
It is still driving however 70 mph is the new top speed

I want to know should I get a rebuild kit and tear the motor down and replace the old engine with new components
Or
Should I find a motor at a u pull it and hope for the best?
I currently do not have the budget to get a crate motor. I only got $500 to fix this problem.

 

Welcome to the forum

Least expensive option would be to pull the engine and fix the problem, put engine back in, complete rebuild it is up to you
Assuming your labor is free, lol

You need to pull at least one head to remove piston with bad rod bearing to replace wrist pin/bearing
New oil pump
new connecting rod and bearing
But crank will be the big deal, especially if you are still driving it, if journal is damaged then price just doubled, because you will have to pull the crank, get it fixed(turned) then new bearings on all
You can pull the engine and oil pan, and pull the bad rods cap to have a look at the crank, if it looks OK then pull that head to replace just those parts

If crank is damaged then shop for replacement engine, avoid 2004-2006 3.0ls, but outside of those 3 years 1999-2008 3.0l from Ranger or Mazda B3000 will work as replacement
Regardless of the year of replacement engine you will need to swap upper and lower intakes to match your 2000 Ranger wiring
Rangers had gas only and flex fuel 3.0ls, this doesn't matter except for fuel injectors, but it you swap over your upper and lower intakes then it won't matter at all since you will be using the correct injectors for your 2000 computer