I'm rebuilding the top end of my 2000 4.0. I'm about to put the new heads on and I was going to chase the head bolt threads before doing so. I got a M12 1.75 thread chaser and it won't go into the block more than half an inch or so.

Am I using the wrong size chaser? How much force should I use to chase the threads before I should worry about stripping the threads?

 

It would be the wrong one if thats the case.

2000 Ranger will have a 4.0l OHV engine, which is different from the 4.0l SOHC engines used in explorers from 1997 and then in Rangers in 2001 and up.

Try the bolts on a hole and make sure they go in smoothly.

Then if you have a tap and die set find the die for that bolt and then the matching tap