UpperDecker

Hello everyone looking for some advice/help with what would possibly be the issue or multiple. A week ago my 99 Cherokee sport started acting weird by fluctuating oil pressure via gauge with acceleration and slowing down which it didn't normally do. Yesterday I did an oil change that was past due but thought I may have just been low on oil. To my surprise it wasn't but I replaced my filter as well. Afterwards I noticed a ticking noise coming from the engine when I'm actually driving. I don't seem to notice it while it idles. Another key piece is now my gauge reads zero and my check gauge light comes on. It will fluctuate ever so often by going up to maybe 10 to 20 at most. But for the most part it just stays on zero and sounds awful during acceleration. Any ideas on where to start? Thanks in advance

Dave51

You could check oil pressure with a mechanical gauge but with all the engine noise IIWM I'd go straight to dropping the pan and checking the oil pump and for debris on the bottom of the pan.

And stop driving. Noise = engine damage.

UpperDecker

I'll give it a shot. Just found it strange that right after an oil change my gauge went to basically to a constant zero and the engine ticking started. If acceleration it too quick it sounds like it's no longer getting oil. It has that higher pitch from the engine until it shifts but nothing is overheating as of yet and I don't want it to get to that point or worse. I've done plenty of oil changes but this is definitely a first for this

Dave51

Were/are you using Fram or Wix filters (sorry, inside joke)?

IMO it doesn't sound like going from where you were to where you are is that big of a change. There's a major malfunction of sudden onset and rapid deterioration so the short list is pretty short. You'll need to check the distributor, pressure relief valve and the gauge (maybe your oil pressure is not zero, but it's certainly nowhere near normal)(cause if oil pressure was really zero you'd have rod noise. That you don't seem to have that (yet) that's a very good sign that there's no irreparable damage)(that said, while you're under there might be a good idea to check rod bearings). Anyway, to address your observation, it would seem that only the lifters are starved at this point (at least until you accelerate).

PilafSama

I'm in the same boat. The oil pressure gauge will rise to 80psi at times and everything will feel fine and no odd noises from the engine. Changing out the oil and oil filter today and the oil pressure sensor this weekend. I'll report back if that solves the fluctuations, if not I may take the advice above of changing out the oil pump.

GreaseMonkey17

Before you waste any time or money on it swap out the oil filter with another new one . Doesn’t matter what brand it is all can fail .

Dave51

Certainly aware of our earlier discussions, but OP developed issue while one filter was on engine and has already changed filter x1, so IMO filter failure has been ruled out.

Could certainly cut both filters apart (if the old one is still available) but IMO the likelihood of catastrophic filter failure, which is already rare, to happen on successive filters is nearly impossible.

Dave51

Besides if OP does the job a pan gasket is like 20 bucks. And if he is blowing up successive oil filters then the oil pump needs to be checked anyway.

Dave51

At the risk of restarting Oil Filter Apocalypse, what brand do you use?

TrailerTrash

If you changed the oil filter from the top like I do then you may have bumped and broken the oil pressure sending unit. I did the exact same thing. But that wouldnt account for the noise that is the anomaly here

GreaseMonkey17

Dave it is in my experience that sometimes you have to “ pick and choose” symptoms that a “customer” tells you . Often one has nothing to do with the other . There was no noise prior to oil change if I read it correctly , just fluctuating pressure on the gauge . Which leads me to believe it’s a possibility . Yes it’s rare but not unheard of. I try to remind myself to “ keep it simple stupid or The KISS method” when doing any diagnosis otherwise you can replace an engine or transmission over a .50 cent problem . Just my .02

BillyBoy

Any body have a picture of a pressure relief valve?

Dave51

Sure:

Dave51

Interesting Points About Oil Pumps in the Cherokee XJ That Can Be Used To Impress People At Parties

The lubrication system of the oil pump is unique in that it uses unfiltered oil.

The lifespan of an oil pump is about 60,000 - 70,000 miles (say the people who sell oil pumps).

In the absence of symptoms and good maintenance practice, expecting 200,000 miles out of an oil pump is not unreasonable.

Everybody's vehicle on this forum is at least 18 years old.

You can put an HV pump in to sound cool by saying you have an HV pump but keep in mind that you have to pound out the bottom of the oil pan with a ball peen hammer.

If you have low oil pressure with no symptoms and are changing out the oil pressure sensor, purge out the receiving hole cause it could be clogged with sludge.

If you see someone with $360 worth of Bilstein shocks who say it's "the greatest thing they've ever done for her" (they always call their XJ "her")(frankly, that causes some ugly images to appear in my head) ask them if they spent the $74.72 for a new oil pump lately.

If you see someone with $2000 worth of tires and rims see above.

cruiser54

If it didn't tick or have low oil pressure before the oil change, I would swap filters for sure.