I've got a 05 Ranger with 3.0 and 280k. It has a leaking valve cover gasket and rear main seal. The main issue is it has the defective exhaust valve issue. It's been slowly getting worse and one cylinder is low on compression and sometimes missfires when cold. I love my truck so it's woth fixing. What is my best option, get the engine rebuilt or swap a used one in? I'm guessing a rebuild will cost quite a bit but a used engine could also have some hidden problem.

 

If it's not burning oil and generally runs well, Why not just do the heads?

 

i was quoted 800 to fix timing cover alone so figured replacing the whole engine maybe better

 

If you can handle the down time, I'd get your engine and heads rebuilt.
Next choice would be buy a rebuilt long block.

As to a used engine, the 3.0 hasn't been used since 2008, so it's already 13 years old.

 

yeah that's a good point and many are even older. I would much prefer the 4 cylinder but it's hard to find extended cabs here with it