10W40? I always thought that was for diesels. It does make sense that since it has 227k it would have some loose parts. I'll try anything at this point. I want to be driving this Jeep as much as I can. The less miles I have to put on my '05 Pontiac, the better.


Edit: Wait, 15W40 is for diesels. I should know, I'm a trucker and took diesel mechanics

 

Grab a Wix, Napa, Mopar or Purolator filter and a jug of Rotella T 15/40. Or Delo if you like.
Yeah, the "diesel" oil. Good stuff in gas motors with a little wear to them.

 

It should be the common sense first step, but I didn't see it mentioned. Did you check your dipstick? Are you low on oil?

 

Ok,

I changed the oil this evening (15W40). I used a Wix filter. Still has fairly low pressure on gauge (20psi at idle). It is still ticking in the top end. I listened closer while I looked under it for oil leaks, and there is also a rattling/knocking noise coming from the lower end (rods, bearings?).

Any ideas?

 

Did you check it with the mechanical guage yet? The oil pressure sending units go out quite often on these. I wouldnt touch anything else until the oil pressure is confirmed as low.

 

20# at idle isn't bad. Minimum spec is 13# hot idle. What's the pressure at higher revs?
Ticking from the top end is fairly common, esp. lifter noises, as is some mild piston slap. How loud is the noise in the lower end? Check the flexplate bolts perhaps?

 

With that said, i beat on my 9psi at hot idle 4.0 from 225k to 280k miles, using cheap 15w40 oil, cheap filters, going 4k miles between changes and she is still going strong, oil pressure hasnt gotten any worse.

 

Agreed. Do you even know you have a problem? Until you see a mechanical gauge giving you that low reading, all bets are off.

"If your gauge is wrong, the next thing to check would probably be the oil pressure sending unit. Disconnect the unit and check the warning lamp or gauge reading. If the warning light remains on with the sending unit disconnected, there is probably a short to ground in the warning lamp circuit. Likewise, if there is no change in a gauge reading the problem is in the instrumentation not the engine.

Bad oil pressure sending units are quite common, so many technicians will replace the unit without checking anything else to see if that cures the problem. This approach might save you some time, but it is risky because unless you measure oil pressure directly with a gauge attached to the engine you have no way of knowing if pressure is within specifications or not. Most warning lamps won't come on until oil pressure is dangerously low (less than 4 or 5 lbs.). So don't assume the absence of a warning lamp means oil pressure is okay, especially if the engine is making any valve or bearing noise.

If a check of oil pressure reveals unusually low readings, check the filter. It is possible the filter might be plugged with gunk. Ask the customer when he last had the oil and filter changed. Or, replace the filter and see if that makes a difference.

The next step would be to drop the oil pan and check the oil pump pickup screen. If the screen is clogged with debris, you have found the problem. Also, check to see that the pickup tube is properly mounted and positioned, firmly attached to the oil pump (no leaks) and is not obstructed.

If the oil pump is mounted inside the crankcase, the next step might be to remove and inspect the pump. Open the pump cover and measure clearances. Also, check for scoring or other damage. A broken pump drive would tell you something entered and jammed the pump. If the pump is worn or damaged, replacement is the only option.

If the pump appears to be okay, the next step would be to measure the rod and main bearing clearances. Check the clearances on the main bearing closest the pump (since this has the greatest effect on pressure), and clearances on the furthest rod bearing (since this will show the greatest wear). If the bearings are worn, they need to be replaced. But before you do so, carefully inspect and measure the crankshaft journals to check for wear, scoring, out-of-round and taper. If the journals need attention, the crank will also have to be reground or replaced.

Other checks might include camshaft end play, and/or pulling a valve cover or the intake manifold to check the cam bearings and lifters. Remember, excessive clearances or leaks anywhere in the engine's oil supply system can contribute to low oil pressure."
http://www.aa1car.com/library/us1097.htm

 

OK so let me be curious. Here non detergent. Diesal oil will be fine I'm curious I threw 30 qts out on the curb. A few months. Bk found it in the back of my attic along with 100 plus filters

 

don't use non-detergent oil for street purposes. Diesel rated oils are high-detergent if that is what you are asking?

Now I'm curious...what did the filters fit? Someone really stocked up, lol.

 

I'm guessing. A cat motor. The Guy that lived here before me from a international. And yes I mean high detergent. My bad was in blue. Jugs UN opened

 

I DJ if they where all oil though. Some where long and some where medium and some where fat n small

 

mech gauge test would be a good idea to help you sleep well. the ticking...also...might be those injectors. these engines do have a good deal more rattle than say an LS1 or honda k20 but they also have noisy ticking injectors. a lot of guys {including me if i keep mine long} go to the 703 3rd gen injector set

http://www.ebay.com/itm/330657234572...#ht_3155wt_905


and or 784s if you're an obd2 truck

as others have said, if you do have an actual 20psi at warm idle, that's not damaging. the general rule is 10psi per 1000rpm. since the average cherokee never goes above 5000 if you have 50psi max pressure with the motor spun up you're fine.

low oil pressure clacking has a very distinct sound. if you've ever heard it you'll know what i mean. it's completely different than ticking or knocking.

a few years ago i detonated a hole in cyl 7 of this corvette i was tracking. the oil pressure dropped, the lifter rattle was very distinct at idle. not to mention the cloud of smoke the car was making as i drove home. looked like spy hunter. poor car lost over a quart of oil out the tailpipe in less than 25 miles

 

I hit a money shift in my L82 and snapped a rod. The noise and smoke that ensued was unmistakable. Nothing at all like lifter noise, lol.

 

Well, after all this discussion I would tell the original poster just to drive it.

If he starts mucking with it, it'll probably mess up.