lifter is stuck

I have a 94 Cherokee Sport with 4.0. The lifter in the very front is stuck. The rocker arm is loose and just flapping around. All is torqued appropriately. I have an additive in the oil now that is supposed to free it up. But, I was wondering if anyone knows of an "old school" way of freeing the lifter by just removing the valve cover. Seems like I remember my dad putting an old push rod down through the block and tapping the lifter with a light mallet. I think he would turn the engine so the cam would push up on the lifter and then he would tap it back down if it didn't move on its own. etc etc. Anyone heard of that technique.

Tapping it might work, but the issue is that it's not pumping up with oil pressure. Has the oil been changed regularly, and have you had any other lubrication issues?

Hopefully a tap or the cleaner you've put in will take care of it. If not, it might be time to take the head off and get a new set of lifters. (and other parts while you're in there!)

How many miles?

oil has been changed regularly but the last head I had on was cracked and the car got pretty hot. Swapped heads, but didn't know I was supposed to put the rocker arms and bridges back in the same place. Mileage is at 184,000.

After a really bad overheat, and since you obviously know what you're doing, replacing the head you might want to just swap out all the lifters, pushrods and rockers.....

But, the easy on the $ method of tapping could work...let us know if it does.

Thanks for the quick response. I am going to drive it for awhile and see if the lifter frees itself. If not then I will pull the head and replace lifters, rocker arms and pushrods as you suggest. This is old jeep is excellent transportation and I'm beginning to know it like the back of my hand. Can't let it go. Must fix it. I'll get back to you with the end result.

Welcome. I like to keep my oldie but goodie running forever too. These Jeeps just soldier on, seemingly forever. But I hope it frees up on its own and stays that way. How long did you plan to drive it with the valvetrain flopping around? Not long I hope.

I've used stuff called "Valve Medic" available at Pep Boys. It did the trick on my old VW Vanagon (still have it in process of rebuilding now for 2 years - need the time)) and my current Chevy Cavalier and Acura Legend - both with 270,000+ miles. Good fix for the time being to extend the inevitable need to rebuild.

Update on lifter problem. I couldn't free it by tapping on it (maybe it wasn't stuck but had just gone bad). So, since it was the very first lifter at the front of the engine I just lifted the head enough to pull the old one and drop in a new one. Set the head back down torqued it and away I went. It's running fine. Obviously not the optimum way to fix it but I had no time or money.