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Sudden 80 oil pressure!

A

aallppiinnee

NAXJA Forum User
Location
Virginia
Just noticed today my XJ is reading 80 pressure...not sure how long I failed to notice.

After everything was warmed up, at idle it drops to 55, but under any sort of load it goes to 80. When it was still warming up it was 80 regardless.

At operating temperature, engine off, key in the ON position it reads 35.

With the oil cap off, engine running, I see little oil collecting under the valve cover. Everything is coated in a little oil, there is a little bit of flow at the bottom a few mm deep, I see a little oil collecting above the moving parts, but I can basically see the full length of the nearest valve spring. I confess I don't know what I should be expecting when I look.

Otherwise, sounds find and ran fine today, normal operating temp in 50 deg weather (though I brought it home as soon as I noticed).

1999 I6, 120k, always fed syn blend.

Thoughts?
 
Last edited:
Sounds like a bad sensor/possible sensor wire knocked loose.

Putting a manual gauge on and testing the oil pressure is ALWAYS a good idea, but I would probably just swap the sending unit--buy one from NAPA or the dealer.

I like quality parts in the "OH S*IT" applications.
 
I see. It's located near the filter. Well, after the blizzard on the east coast I was definitely slamming into a lot of deep and icy ruts, not to mention all sorts of salty slush.

Is a manual gauge something a lot of service stations have and can check quickly, or does it require the old unit be removed? Based on the way the part looks, replacement seems simple enough with a wrench.

joe_peters said:
Sounds like a bad sensor/possible sensor wire knocked loose.

Putting a manual gauge on and testing the oil pressure is ALWAYS a good idea, but I would probably just swap the sending unit--buy one from NAPA or the dealer.

I like quality parts in the "OH S*IT" applications.
Click to expand...
 
hubs97xj said:
Showing 35psi with the engine off, I'd replace the sensor.
Click to expand...

yeah I didn't get a look at until the engine was already warmed up

it's been off for at least half an hour, rad temp is about 150deg and it's still reading about 35...which of course makes no sense.

I just wanted to make sure it's drivable without destroying the engine (like if the pressure was reading 0). I appreciate the input gentlemen.
 
aallppiinnee said:
yeah I didn't get a look at until the engine was already warmed up

it's been off for at least half an hour, rad temp is about 150deg and it's still reading about 35...which of course makes no sense.

I just wanted to make sure it's drivable without destroying the engine (like if the pressure was reading 0). I appreciate the input gentlemen.
Click to expand...

Your description sounds almost assuredly like the sending unit. When they fail, they usually fail on the "high" side, rather than the low side, where verification with a mechanical oil pressure gauge is highly recommended.

As mentioned, you can verify it if you want but if it were my vehicle, I would just replace it if you don't have a mech. gauge.

I buy my oil pressure sending units directly from Jeep for best reliability/accuracy/mating with your factory gauge. Probably in the $40-$50 range.
 
so your saying sence my oil pressure needle is pegged , my sender is bad?
 
I've had this problem for almost a year. Got in jeep at lunch and gauge peged.
Specs, 2000 XJ I-6 Synthetic oil

Of course the first thing i did was disconect the sender, threw my trustry Snap-On oil pressure gauge on and found 75psi at idle.:wierd:
second I swaped out a couple different brand's of oil filters, with no change.
Third I said screw it bought a new Hi volume Melling pump, Fired up the motor and the oil pressure gague pegged even faster and stronger then before. As the original poster mentioned 55-60 psi at idle, and then spiking to 80 under load, was exactly how my jeep acted when it started acting up. After the new pump I've got 80 all day.
There appears to be no presure relief valve of any sort on the oil filter housing from what I saw looking at one i at the junkyard.

And here's another weird one , the gauge shows almost 55-60 psi with the KOEO.

I gave up worrying about it a long time ago and am hoping to find somthing when I tear down the motor.
 
If you are running a Fram filter, change it.
 
aallppiinnee said:
why do you say that? matter of fact it's got a Fram (probably an Extended Guard, if not then a regular Tough Guard) in there right now

been attached for about 3k miles now
Click to expand...

Could be he is referring to anecdotal evidence that the low-line Fram filters have issues--low oil pressure, nitrile rubber instead of silicone anti-drain back valves, and problems with the by-pass valve.

Go here: http://minimopar.knizefamily.net/oilfilters/reference.html

Scroll down to the Fram filter section. Educate yourself and make up your own mind.
 
so by that chart if you get a tough gaurd fram then its got the silicone anti-drain back valve so its not overly bad is it? well actually it does have kinda crappy element surface area. also if you look the mobile one's have nitrile rubber diaphram
 
I run the Wix/NAPA Gold (same thing).

Have you converted to the SAE filter adapter to get rid of metric filters? Adapter part number is 53007563AB @dealer. After changing to the SAE I started using the Wix 51515 filter, which has a one quart capacity, twice that of the stock metric filter, and will fit in both the vertical and horizontal positions.
 
I just got one of those adapters from the dealer. It's not as long as the adapter on my 92 HO motor or the one on my Renix. Threaded part is the same but doesn't have the long tube sticking up. Did you notice that, Joe? I'd like both my Jeeps to use the same filter instead of one being SAE and the other mumblemeters.
 
cruiser54 said:
I just got one of those adapters from the dealer. It's not as long as the adapter on my 92 HO motor or the one on my Renix. Threaded part is the same but doesn't have the long tube sticking up. Did you notice that, Joe? I'd like both my Jeeps to use the same filter instead of one being SAE and the other mumblemeters.
Click to expand...

Way shorter than the original Renix adapter, but it doesn't make any difference, works great. :cheers:
 
Wix is good; sadly a lot of their filters are being made in China and stuff... (filter for fiancee's civic for example) and a lot of purolators are going China as well, over half of their air filters are made there. I don't really trust Chinese goods, and I don't like to support companies that are moving production overseas, so I'm using Baldwin/Hastings filters or Fleetgard (Cummins filter). I think they're better made than the wix, which the ones I've used are far better than fram or whatever. Fram= junk. cardboard endcaps, I had a 0psi issue with a Javelin with one. NEVER again will I use fram. Sad... they used to be really good. Now I only use industrial filters, or brands that are well respected in the heavy equipment industry (wix baldwin hastings fleetgard...)
 
I was going to say my guage sometimes goes above normal position, but then usually settles back down... not the usual fluctuation either, I know what that looks like... I have been running FRAM on all of my vehicles for years, as has my family with absolutely no issues thus far.... I haven't had any issues with running the FRAM filters on my Heep, well nothing that wasn't already there prior to me purchasing the Jeep... But maybe I am just too new to the Jeep yet, maybe it will come around to bite me in the a$$... then it will be time for that budget stroker build I want to do anyways...
 
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