get3coffinsready

post up a video, it might be nothing.

SteveMongr

I am in a similar position. 2000 WJ 4.0 195,000.
Hot idle oil pressure is 4 psi
Driving pressure is 38 psi.
Check gauges light come on at isle due to low pressure.
Tick-tick sound from lower end, oil pan. (On previous 4.0 motors I have only heard the tick from the valve train).
It has the notorious 0331 head but I am not seeing any cracks, or milky oil or oily coolant.

bryanintowson

Sounds like your oil pump may be on its way out. I have heard here that 4.0 oil pumps begin to fail around 190K.

storm101

Sender swap doesn't require draining, yes a stethoscope would be great, most people don't know they exist though for some reason let alone have one lol, so high five there.

The evap canister is also a good point, just gotta take some time and look around and see what's what, and at least RULE OUT stuff.

Piston skirts and the like are not a tick by any means, it's a straight up slap/knock noise, that's also no fun to find.

Just start simple and work into this with some organization and methodically, you'll figure it out, don't get overwhelmed from the Internet just yet lol.

Also as stated, if you can get a video of it, that's always helpful, video in the engine bay at idle/rev it some- head underneath and poke around as well with it.

Also an odd question but what brand oil filter you running? I've heard of the orange cans of death creating some odd noises as well if installed (Fram)

Another way to check for an exhaust leak would be to vaccum induce some seafoam...look for the white cloud down the system...

99Justin4.0

Thanks storm101. You're like a Jeep forum psychiatrist. Internet high five right back at ya! I got the day off, so the work begins. I will try to get a vid on here. I just got a chromebook and don't really know how to do stuff like that on it yet but I'll try.

As I said before, I left a lot of money in the budget. I found a complete brand new ATK head with the 0331 crack problem eliminated for under $500. Obviously I don't know what the sound is, but if it's up there, would that be a wise option?

I've never worked on an engine (aside from external engine components) that wasn't DOHC, so this whole set new system to me...

I almost forgot... these are NOT interference engines right?

99Justin4.0

Well I pulled her forward like 2 feet about 3 minutes before I pulled the old sender. Didn't think to let the oil settle longer. Leaked a little...

Definitely looked like it was leaking through one of the prongs. Cleaned everything up, installed the new one and it works now.

One thing checked off.

99Justin4.0

Now the freakin airbag light is dinging every other minute when I drive it. Any clues on that?

I looked under the oil fill cap and it's clean.

Oil is about 44psi all the time now.

99Justin4.0

I know I'm posting like a maniac, but any opinions on just an all out seafoam treatment?

storm101

Wouldn't bother with a head unless you need it, if she's not leaking coolant mysteriously or any symptoms of a cracked head don't worry, plus if you do happen to have a larger issue, it's going to be in the bottom end at this point I'm guessing...unless there's something seriously up with the valve train. 500$ will get you a good used engine to drop in if needed as well....ask me how I know

I havnt done anything internally really other than diagnosing stuff when I had a busted skirt...currently getting ready to swap a head on a new rig I picked up as well, so some info is fresh lol

Good to see the sending unit is back in proper order, the air bag idk that's odd, check the harness around where you had to unplug the sender, maybe something is loose or rubbed open? Check the fuse too.

Seafoam is helpful from my experience, for the price it's never a bad idea IMO.

99Justin4.0

I'm really leaning towards a leak somewhere near exhaust manifold. I've been driving it around town and it honestly runs perfect. I put 9oz of seafoam in the oil, and in a hundred or so I'm gonna do a full oil change. I'm leaning towards Rotella T6 5w40, Wix, and some Lucas Stabilizer.

In other news there's some kind or Whhhhhhrrrrrhhhhhhh sound constantly from what sounds like the back when driving. It sounds a brake rub or something dry. Or road noise on a not so smooth freeway... I put her in neutral at about 40mph and it still did it. I hope wheel bearings are easy on these.

I'm prepared for a new engine (when neccessary). I've done a few swaps, including completely different engines and harnesses. I swapped out my 1.8L block with a 2.0L and used the same 16V head in my 79 Scirocco in less than 10 hours the night before a car show once. A same engine swap on this looks pretty easy. I just really don't want to have to do it for a while.

Now the rear end thing is bugging me the most.

SteveMongr

If you suspect a rear wheel bearing or pinion bearing is going bad, they usually put off excessive heat that can be pinpointed with an infra-red temperature gun.

99Justin4.0

Very good idea. I'll see if Harbor Freight has one for cheap. If you don't have Harbor Freight where you are it's like the dollar store for tools...

extrashaky

Cool tip.

HF has one that's normally $30, but they put it on sale around holidays for $20. Then you can use your 20% off coupon (or 25% off occasionally) to get it for $15 or $16. And be sure to use one of the freebie coupons also to get your free flashlight, magnetic parts tray, multimeter, stick up light or whatever the hell else they're giving away.

I have so many free HF flashlights. I leave them scattered all around the house and in my vehicles. They break. I throw them away and go get more.

99Justin4.0

Got a temp gun, some ramps, and chocks. No free flashlight this time...

I'm armed and ready to attack every minute of daylight available that I'm not at work. Between the tick and the wuhhhhhrrr I'm going crazy. I drive with my *** clenched. I feel like I'm crossing a mine field every time I drive.

These ramps kick ***. It's awesome having a vehicle I can pretty much already squeeze under, then just drive up some ramps to make it even easier.

JSJJ388

My 94 ZJ also sounds like a diesel when running. I pulled the valve cover off and everything looks fine. Mine sounds like it is in the top end but its loud enough to hear across the parking lot at work. Also no power loss or anything. just sounds like a diesel.