Ok, I have searched and searched Google and every forum I can find, and most posts either go unanswered, or the OP gives so little detail that they can't be helped. So, I'm gonna try to lay this out, and see if you guys can help me before I pull the head AGAIN. Sorry in advance if I'm rambling, just trying to give you the full picture here.

1999 Grand Cherokee, 4.0, 4x4, 26x,xxx miles

So I traded my hunting truck on a 99 Laredo for my wife. It's a 4.0, 4x4, auto trans. Got it off a young kid and it has not been taken care of at all. I have spent the last month fixing all kinds of ridiculous issues, and many very common problems. When I got it it had no clutch fan, was overheating at idle, and had a slight blow in the head gasket. Also had 2 broken push rods, was chirping like hell, and was generally a mess. I pulled the head, checked for cracks/warp, lapped valves, and reinstalled with new melling rockers, new melling pushrods, Felpro gaskets and MAHLE head bolts. Also installed a clutch fan, cause ya know, ya need that.

I pulled all the lifters, soaked in oil, cleaned them up, soaked again (overnight) before putting the head back on. The lifters seemed fine, but I think this was where I went wrong. I also soaked the rockers and pushrods, which is not necessary, but good habit IMO, no such thing as over oiling new parts.

Fast forward, truck ran great for a few weeks then started chirping again.

The current issue: no oil to rockers. I mean some are bone dry, some have a comically small amount of oil coming through. I checked the oil pressure with a mechanical Gauge, had around 15psi at idle, which while acceptable to some, is low for me. Rather than ****** the motor and build it I put a new high volume oil pump in, MAHLE I believe. Or maybe Melling. Anyway, here's the current situation:

​​​​​- 60 psi oil pressure with mechanical Gauge at idle, 65+ at 1500rpm
- Fresh oil & filter
Still dry up top. Cam looked good from underneath, no scoring or flat spots I could see. The truck runs good, but has awful valve train noise, and isn't getting oil. I need opinions on where to go from here, I don't want to throw parts at it, and while I think it has to be the lifters, I don't understand how it can be. Also, with the engine spinning over and pushrods out, I get oil oozing from the top of the lifters, and when I pull the pushrods after running, there is oil up the rod about 1.5 inches. I have pulled and cleaned out the pushrods again, but there was nothing blocking them.
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SO, pull the head and replace lifters? Any other options here? PLEASE HELP, this is driving me nuts. Ive had literally dozens of these 4.0 Jeep's, and had never had this problem.
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thanks in advance, sorry for the long post

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Also, I numbered the lifters and out them back on the lobes they came off of

 

Welcome to the forum.

It sounds like the oil passages are partially obstructed.

When I updated my engine I disassembled cleaned and tested all my lifters. Most were bottomed out when I started, All were fully functional when completed.

There is a pressurized oil galley that supplies oil to the lifters, through a small hole on the side. The lifter pumps up the oil to the rocker through the push rod small center hole. The rocker also has a small hole.

All of those those small holes must be unobstructed.

 

First of all, the 99 4.0 Laredo doesn't use a clutchfan unless it's a tow package, then it will also have a factory trailer hitch, aux trans cooler, and trailer lighting module. It just has a single speed electric fan that is controlled by a pulse modulated relay to function at lower speeds and is triggered by the computer (PCM).

If you have had several 4.0 jeeps, you know the valve lash is not adjustable, HOWEVER it must have the lifter preload checked any time the head comes off and modifications are made. A valve refacing is a modification since it seats the valves deeper in their seats and causes the stem ends to be higher unless trimmed. The bent pushrods tell me the lifters were bottomed in those cylinders before you took it apart.

In order to check the lifter preload, each cylinder must be at TDC compression and the pivot bolts tightened to zero lash, then 3/4 turn. I have a text explanation of the procedure, but not a good picture of it, but I'm sure other guys do.

 

Thanks, I am pulling the head again tomorrow. I have new lifters soaking for it, I will check lifter preload this time and set that, and I plan to try to blow out the oil galley with air, anything else I should do while I'm in there?

 

If the lifters are new / unused then soaking is fine.

If the lifters are from another vehicle, then disassembly and cleaning are the best option, until the internal parts slide freely.

The central pushrod passage must be clean. The small rocker opening must be clean.

Good luck.

 

Got it! New lifters got it running good again, with plenty of oil to the top end. 1 lifter was blown apart and a few were seized completely. Got it all done yesterday, just have to button up the hoses and add coolant this morning.

Thank you all for the help!