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Hello JeepGarge forum... Could anyone tell me what the reason could be for my oil pressure to be running high in my 2002 jeep grand cherokee 4x4?? When I first start the jeep the gauge goes all the way to H. When I am driving it stays there but when I am stopped it goes down the the 3/4 mark. The check engine light is not on. There is no other engine noise out of the ordinary, plenty of oil & "normal" oil drips, normal running temps.

I committed a sin & deviated from my normal oil & tried to use a "supposedly better" oil, Valvoline Max life. I didn't like how the jeep "felt" & drove. I noticed this 2 days ago & am pretty good at keeping an eye on my gauges. I thought that since this has never happened before, it must be the Valvoline oil. I did a oil change yesterday, going back to my normal oil and it is still doing it.

I'm thinking it is an oil pressure switch has gone bad, but any other thoughts?


Stats:
Model: 2002 Jeep Grand Cherokee 4x4
Miles:186,000 (engine changed @ 103,000)
Mods: none
 

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Oil pressure sending units on these motors are notorious for acting funny and failing (4.7 motor). I verified mine with a true mechanical gauge.

If it is not a bad sensor then more then likely the oil pump's built in pressure relief valve is malfunctioning.

HTC Thunderbolt 2
 

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I would try a new oil pressure sensor. They are fairly inexpensive.

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my 2013 JGC oil pressure was 90+ today after oil change yesterday. previously - with year old conventional oil compared to the semi-synthetic the shop used (despite my request for conventional) - the oil pressure was averaging about 40-50. i read that the OEM oil filters have an oil pressure relief valve, so if the shop did not use the correct filter, then couldn't this cause artificially high pressures? i just think it's a huge coincidence that the pressure is so high with clean, slicker oil the next day after a change. there are no error codes or engine lights. and the pressure goes between 52 - 96 while accelerating and decelerating. just not seen this before.
 

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The valve in the oil filter is there to let the oil bypass the filter, in case the filter gets clogged. Unfiltered oil is always better then no oil. Do you remember what grade of oil was in there before and what they have put in now? (example 5W30).
Using a higher grade oil (example 10W40 instead of 5W30) can cause a higher oil pressure.
 

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Change the oil psi sensor. They typically peg high when they go bad.
 

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The valve in the oil filter is there to let the oil bypass the filter, in case the filter gets clogged. Unfiltered oil is always better then no oil. Do you remember what grade of oil was in there before and what they have put in now? (example 5W30).
Using a higher grade oil (example 10W40 instead of 5W30) can cause a higher oil pressure.
The valve in the oil filter is there to let the oil bypass the filter, in case the filter gets clogged. Unfiltered oil is always better then no oil. Do you remember what grade of oil was in there before and what they have put in now? (example 5W30).
Using a higher grade oil (example 10W40 instead of 5W30) can cause a higher oil pressure.
@ FRANGO -
the shop that did the last 0-change also put in the wrong coolant, despite my bringing it along. they first put in semi synthetic and I asked for conventional so that was a HUGE argument despite 3 separate phone calls about wanting conventional oil. after the fussing bout the coolant, the service mgr. claims to have removed both the new filter and semi and replaced it with conventional oil. I am assuming they used 5w20 as it says on the oil cap. that was a year ago December (used to bike everywhere and only put about 5--7k on my Jeep annually). but I have no way of knowing what they used b/c there was white smoke for at least 2 weeks after.

the shop I took it to this time ALSO used semi despite my request for conventional so I really cannot fight the fact that shops do not give a shit what females ask for and he honestly tried to convince me the hybrid/semi synthetic oil IS considered conventional now. lol
 

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oh - forgot to answer your direct question -- on the receipt says 5w20, but who effing knows whether shops actually follow that anymore. they ignored my request for conventional so, who effing knows.
 

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so long story short, the engine went from correct grade convetional to who knows to who knows. unless i see what goes in the truck, i have no way of knowing. they use giant drums of oil (according to the mechanic who gave me a ride0 so my guess is they just out whatever oil they have as they likely do not stock 5 different grades of oil in their little shop. and the same magr told me the car took 5w30. and i corrected him. so who knows what's in there now. the Jeep went from conventional to semi and then "supposedly" conventional, then back to semi. and 2nd day driving is when I noticed the pressure ranging from between 50-90.
 

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Assuming this was an independent shop that changed the oil? One of those quick oil change places?

The filter's bypass valve should not be active with a new oil filter and new oil.
However the new oil filter could be defective with a filter element leak or tear not providing enough back pressure for the oil pump's psi regulator to work properly.
Also a higher viscosity oil than recommended will increase the oil psi somewhat but i highly doubt 90 psi.

If you're concerned about the correct oil, either change it yourself or bring your own the oil and filter to the shop and have them change it.
Then take it from there whether that cures the drastic oil psi swings.
If not, one option would be to have the shop do an oil pressure test with a real pressure gauge.
That would verify if the oil psi is indeed reaching 90 psi and whether the oil psi sensor should be replaced.

Since this happened right after the oil change, worst case scenario could be the oil pump's pressure regulator went haywire for some reason maybe due to a defective filter, wrong filter or incorrect oil viscosity.
 

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Assuming this was an independent shop that changed the oil? One of those quick oil change places?

The filter's bypass valve should not be active with a new oil filter and new oil.
However the new oil filter could be defective with a filter element leak or tear not providing enough back pressure for the oil pump's psi regulator to work properly.
Also a higher viscosity oil than recommended will increase the oil psi somewhat but i highly doubt 90 psi.

If you're concerned about the correct oil, either change it yourself or bring your own the oil and filter to the shop and have them change it.
Then take it from there whether that cures the drastic oil psi swings.
If not, one option would be to have the shop do an oil pressure test with a real pressure gauge.
That would verify if the oil psi is indeed reaching 90 psi and whether the oil psi sensor should be replaced.

Since this happened right after the oil change, worst case scenario could be the oil pump's pressure regulator went haywire for some reason maybe due to a defective filter, wrong filter or incorrect oil viscosity.
thanks for those suggestions. so then the pressure rising to 90 is "drastic". I was worried it was kind of bad. am not driving to work yet b/c I sustained an injury and have been on medical leave since December. but am due to start back, with much more regular driving (not biking). so it sound like I need to get it sorted before the Jeep is used daily.

the shop was recommended by a friend. had 4.5 star reviews on Yelp and Google, but given how he replied to my desire for conventional oil, and that he said the truck takes 5w30, I just don't think hey really care what happens to their customers vehicles. there are several of these places in the area and they all have 5-stars, so not a Jiffy Lube, but not a place I have been to before, though the manager is a neighbor, lives around the corner, so I thought he'd do me a solid.

thx again
 

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Hope you recover fully from your injury fast.
Just curious, what brand and weight (viscosity) oil have you been previously using?

.....the pressure goes between 52 - 96 while accelerating and decelerating. just not seen this before....
This is definitely not normal and you're right, should be sorted out ASAP.
If the 96 oil psi is real, that amount of oil pressure could eventually destroy the main and rod bearings basically ruining the engine. In addition it could also be hard on the oil filter possibly damaging it if not already.

My bet is a bad oil psi sensor which is the first thing that should be checked out, relatively easy to replace.
A bunch of decades ago, i had one of those quickie oil change places change the oil in one of my long forgotten cars.
In the process of changing the filter, they accidentally broke the oil psi sensor.

.....but I have no way of knowing what they used b/c there was white smoke for at least 2 weeks after....
This is also concerning.
Was this smoke coming from the exhaust or the engine bay?
If the engine bay, just oil spillage during the oil change process.
If out the exhaust, do you know if they used an oil flush fluid which i highly DO NOT recommend?
This can cause smoking out the exhaust for a while among causing other problems.
Its also a remote possibility the high oil pressure is real which could mean more than the normal amount of oil getting into the cylinders.

I would take it back to the shop that did the oil change and explain all this to them. If its a respectable shop they should look into this for you. And bring your own oil and filter with you.

Good luck and keep us updated.
 

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hey Mopardo - the white smoke was from the shop who changed oil last year to semi synthetic then said they swapped back to conventional for me and put in a new filter. I was commenting that b/c of all the mishaps and mistakes, I had no way to guarantee what oil was in the Jeep from them.

moving forward:
this is a new repair shop (rx by a friend), with a 4.5 Yelp review, but which threw up several red flags, albeit after the change. bonus, i thought, is that the Mgr is a neighbor who generously offered to take me to from the shop so he could have the truck all day. I showed him a pic of the tire rotation rx by Jeep - front cross to rear, rear straight to front. so I think they got that right, or at least it said so on the receipt.

but upon asking the mechanic what brand/grade oil was in my truck, he said it's in a "drum", and then showed me the receipt which says 5w20. how many shops beside Jeep dealers stock drums of 5w20? so I pretty much believe its not the correct grade at all.

when i asked the Mgr what oil brand they used and he said what my truck called for "10w30", it doesn't and I told him what it took, 5w/20, like it says on the oil cap. so I asked again what was put into the truck, "he said that's what's in there". I said show me a quart of it, and he showed me MAG 1 Semi-synthetic 5x30 from his shelf. so really, who knows what grade is in the truck.

would the incorrect grade, say 10w30, cause higher pressure?

in addition, I sent the Mgr the TSB for the oil pressure relief valve which was a new one that popped up - http://www.wk2jeeps.com/tsb/tsb_wk2_0900918.pdf
just thought the valve was in the same vicinity so why not just check if it's there and in tact. he never said anything about the email. I wonder if they didn't just pull it out to create an issue? it was there and functioning prior to the o-change. and I never had pressure issues before this place. so who knows.

it's what he did say -- the hybrid oil put in my truck is "considered conventional oil now-a-days" b/c no one uses it anymore. but if a customer asks for conventional, then put that in the truck. he should have charge me the cost of conventional since that was what I asked for. which was MAG 1 at $22 for 6 quarts yet I was upcharged 7.87 per quart. just saying, too many flags from the place for me to want to return.

but if the pressure relief valve has been removed by this place, and they put in crappy oil, then I just want to take it elsewhere. problem is, NO ONE I know has a shop they trust in the area. no one. and that's after living here for 23 years. I know I can't be driving if the pressure really IS THAT high. thankfully, I have only driven 2-5 miles at most since (am still on FMLA one more week).

I do need to get it sorted before work nest week though.
 

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may just email him something like this --
HI XXXX,
Since your shop changed my oil, though I have only driven the Jeep 3x for short duration (no more than 5 round trip miles), each time out it's running extremely high pressures upon acceleration -- up to 96psi, though it will go back down to normal at idle. It has never gone above 60s in my ownership.

Upon researching this issue, three things popped up as potential causes;
1. improper grade of oil used
2. the oil pressure release valve went missing or failed (I emailed you a TSB picture of this for inspection)
3. improper install of filter (upside down), or re-use of old filter gasket (not sealing), or missing filter gasket

Please advise.
 

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Spychic, i see this is gonna be an ongoing oil pressure saga.o_O

Switching from conventional oil to a synthetic blend assuming the correct viscosity, trust me that should not cause an instant 90+ oil pressure reading.
In fact the synthetic blend is an all around better oil than conventional.

However, its remotely possible the synthetic blend could of loosened up something or other in the oil psi regulator but i highly doubt it.
Or this whole thing could be a weird coincidence whereby something failed likely in the oil pressure regulator shortly after the oil change. Been there experienced similar with other unrelated problems.

I think there is something else going on besides the oil type.
Did you tell the mngr. about the high oil pressure.
If so, what did he say?


Kudos on your researching the oil relief valve TSB which i wasn't aware of. This could be possibly the cause and the fix.

Before you do anything else, have a shop any shop but preferably a Jeep dealership perform an oil pressure test using a real pressure gauge. And give them a hard copy of that TSB while you're at it.
Shouldn't cost more than an hrs. worth of a technician's wage.
If the test result is indeed 90+ psi and that TSB doesn't fix the problem then there's something going on with the oil pump assembly.

On the other hand if the oil pressure test result shows normal oil pressure then you're looking at replacing the oil pressure sending sensor.

Thanks for the update.
Keep us informed as this is whole thing is getting interesting.
 

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that's really good advice as to how to chase this issue down. thank you!!

i decided against going back to that shop. upon closer inspection, they did not rotate the tires correctly, if at all. i hit curb pass side front the day before and got brown rash, which is still visible on right front passenger tire after "rotation". lol.

i can absolutely ask the dealer to have an oil pressure test done - but in all good conscience - i think i need to drop the oil as i have no faith they put in 5w20 - from a drum at a small independent shop dealing with 50 makes and models of cars a week.

and maybe you're onto something to say that the semi synthetic could have caused an issue with the oil pressure relief valve. especially considering most ppl run that type, but this Jeep is 6 w/only 23k miles on conventional oil. there is a chance that the semi synth did get into spots the conventional oil didn't and loosen something.

i can add that i drove the Jeep for longer today - several more miles than the 3-5 that produced 90psi. the oil pressure backed down to under between 80 after 10 minutes, then kept going down the longer i drove it. at red lights and at idle, it went all the way to 30s. but in the lifetime of owning this Jeep, it has always stayed at 40-50 and on a rare occasion, gone to 60. the fact it is now up and down in such a high range is new onset since the o-change.

thx again.
 

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Blaming a tire rotation for curb rash! Thats is a new one. haha

High oil pressure is nothing to dismiss as it can cause serious engine damage 'if it is indeed real'.
Please get an oil pressure test done if nothing else to ease your mind and let you sleep better at night.

As i and others here have said, its likely a bad oil psi sensor or possibly that TSB you mentioned.

Thanks again for the update.
Curious to know the results of the oil pressure test when you finally get it done.
 

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@Mopardo - i was saying that the curb rash from when I hit a curb Monday caused brown scrapes on the tire sidewall. those brown scrapes were still on the front right passenger side tire after they supposedly rotated them on Tuesday. meaning, if they rotated them correctly or at all, that front right curb rashed tire should have moved elsewhere, with my preference being the rear drive side. lol.

the pressure is not consistently high or over 90, it's just at cold start and the first 3-5 miles during accelerations. the longer I drive the Jeep, the pressure backs down within 10-15 min to the 60-80 range. but the longer I drive the more normal it gets to where in 20-25 min were within average range. also am not getting any kind of warning or error codes which i though a bad sensor would throw.

so no to swapping oil out at Jeep dealer? if the shop used thicker or less viscous 10w30 oil, whether synthetic or not, won't it slow oil getting to where it needs to be, including on cold start ups. and whether being slow to move when cold, or by being thicker perhaps it takes longer to reach places and causes the higher pressures until engine is warm? plausible?
 

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.........the pressure is not consistently high or over 90, it's just at cold start and the first 3-5 miles during accelerations. the longer I drive the Jeep, the pressure backs down within 10-15 min to the 60-80 range. but the longer I drive the more normal it gets to where in 20-25 min were within average range. also am not getting any kind of warning or error codes which i though a bad sensor would throw.......
Maybe i misread your earlier posts but all along i was under the impression the oil pressure was always in the 80+ psi range.
Yes, oil is typically thicker when cold which can produce higher oil pressures until everything warms up to operating temperature.
And yes also, a thicker oil viscosity rating will typically boost the oil psi some.

For example, with my 2K Jeep XJ's analog oil pressure gauge and 10W-30 T5 Rotella semi-sythetic oil....
at cold start the oil pressure is generally 55psi at hiway speeds and after driving a while it reverts to around a steady 40 psi.
The oil pressure at no time exceeds ever 55psi.
The oil pump's pressure regulator's set point is apparently around 55 psi.

Now here's the thing, note i said analog instrument panel's oil psi gauge.
An analog gauge even though driven by the PCM's digital bus still tends to average out any pressure spikes.
The digital oil psi data from the PCM is converted by a transceiver chip in the instrument cluster to an analog voltage which drives the analog oil pressure gauge in my Jeep XJ.

Now take my '18 GC's 100% digital oil pressure gauge.
If i monitor the oil pressure via the instrument panel, the oil psi will spike towards 70+ psi momentarily when gunning the engine at idle then settle quickly back down to around 31 psi.
Further, during hard acceleration the oil psi will also spike up momentarily when driving.

Probably due to a lag or reaction time of the oil pump's pressure regulation system to compensate and the lightning speed of the digital PCM data and the digital oil psi readout instant reaction time.

I don't recall what your Jeep's engine is but if the engine has variable valve timing, it needs the correct factory recommended viscosity oil and type for the cam phasers to work properly.

I think you're going in circles with the oil viscosity/conventional/synthetic/semi-synthetic thing.
I will say this, if the engine has a high amount of mileage and its been fed conventional oil its entire life, it best to keep using conventional oil. However conventional oil is slowly going the route of the dinosaurs.
Using the recommended synthetic blend would be next best.

From what you're describing now, i still think there might be something going on that needs attention.
Only getting it checked out thoroughly as i mentioned will sort all this out once and for all.
 
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