as long as it stays in the middle I dont see the problem, when wheeling it can go above half way pretty easily from my experience (Higher RPM). As long as its not at one end or the other it shoud be fine. should be in the range of 15-50 psi under normal operating conditions.

 

I idle around 40 and up to 55 on the freeway

 

My 99' with 153K when warm will idle at about 20PSI and when driving goes up to 40PSI. This is with synthetic oil. A good rule of thumb would be 10PSI per 1k RPM of the engine. This is normal for an older engine.

 

I just bought an '02 and it runs around 50-55 at Hwy speeds. Please tell me that's normal.

 

Rule of thumb is 10 PSI for every 1000 RPM.

Also keep in mind newer Jeeps use dummy gauges on both oil and coolant and will usually stay around the 50 mark no matter what, even though at idle it will be much lower.

Older jeeps like my 97 show truer values and the oil pressure gauge fluctuates with RPM. Though I don't know what the year cut off was for when they moved to the dummy gauges.

 

My 99' has a "real" gauge.

 

Rule of thumb is 10 PSI for every 1000 RPM.

Also keep in mind newer Jeeps use dummy gauges on both oil and coolant and will usually stay around the 50 mark no matter what, even though at idle it will be much lower.

Older jeeps like my 97 show truer values and the oil pressure gauge fluctuates with RPM. Though I don't know what the year cut off was for when they moved to the dummy gauges.

Can you expand on the dummy guage?

 

Customers were just complaning to the dealers saying the there car is not running right with like a 10 lb oil pressure Thinking thats not righon the older models which is completly normal at the normal temp so they put dummy guages in to stop the complaining. As long as your oil pressure goes up when drivng you should be fine. Maybe a problem if its at 0 of course either the guage or the motor but when there is a true low pressure you will hear some kind of knock.

 

Can you expand on the dummy guage?

Dummy gauges just show highs and lows of psi. People who were mechanically disinclined thought something was wrong when the gauge would fluctuate so they started using these dummy gauges instead.

 

^^^^Yep.

 

Cool! Thanks guys.

 

HAHAHA half to 3/4!

 

Good info. I didn't know that about the dummy gauge. I guess that's what my 04 does as the needle sits just over the half-way mark until the motor is off.

 

My 2000 TJ has a real oil pressure gauge which fluctuates with RPM's. Must be after 2000 when they switched...

 

my 2001 has true gauges. I can watch my oil pressure rise with rpm.

 

WOW! I just learned something. Wonder what kinda gauges I have in the 2003 4.0? I've only had it a couple weeks, I know what I'll be checking out tomorrow.
Thanks for the info.

 

Guess my '01 TJ has real gauges also then as it does flucuate with rpm's, although not very much.

Going off the top of my head, I'd say my oil pressure is between 40-45psi just about all the time. I think that's what that line is. Might could be 50-55 psi, but I think I'm remembering 40-45 as more like right.

 

My 04 has the dummy so it was either 02 or 03 when they switched it.

 

I'd have to guess 2000 was the last year with a "real" gauge. I have a late 2000 build year.

But yeah looks like I'm normal. Thanks guys

 

my BMW has a "dummy" gauge and its oddly comforting

but i dont think its as bad as you guys describe - i tap in to the computer and i can see the true collant temperature and it will start to move if the car gets too hot. I do like that under normal conditions it never moves - and the few times i see it move i know there is something wrong, so it can work both ways, and it gives plenty of time.

 

along the same lines - on oil pressure

I've got a '97 wrangler - 4 cycl - and for the most part the oil pressure reads about 42. Twice in the last month, both times the car was idling at a long light, the pressure started to fluctuate, and then dropped with the warning light/buzzer going off. I tapped the gas and the pressure kicked back up. Now a lights I keep an eye on the pressure and if it starts to drop, tap the gas. When the car is actually moving, the pressure is steady at 42.

The mechanics reply was $500 to replace the oil pump, which he claims commonly goes on Jeeps. Any thoughts? Real problem, something going, or basically normal.

If there were just idiot lights, I wouldn't have notice anything, except for the two quick lights/buzzer.
thanks in advance,
joe

 

My 2005 sits in the middle, but climbs while under load so it cant be a total dummy guage.

 

Mine is 2005 and does the same. This should be normal ??

 

Normal pressure has gone way up!

My 2002 Wrangler 4.0 with 172,000 miles normally runs at about 40-50 PSI at 50-55 MPH. In the past couple of weeks it has begun showing progressively higher pressure to about 78 PSI at 50-plus MPH, always stopping just shy of 80 PSI. Only 2,500 miles on oil and filter change. Oil level is at full line. Am I causing damage at 80 PSI? Why would the pressure just start increasing? Should I try replacing the oil filter or replace the guage? Is there any way to electrically check the guage? Thanks, guys!

 

Most likely just a bad oil pressure sender, replace it with a Mopar replacement. Aftermarket oil pressure senders have a bad reputation, especially store brands. This is a very common problem with TJs.

 

Jerry, how bout the inverse? After warm n driving awhile (00, 4.0 auto, 137k, ) and at idle, always at 20 psi...exactly on that mark. Now a few months after chging oil sensor, now idles at 1 full tick mark Below 20.
Btw, used MOPAR sensor

 

Mine always runs extremely low. Below the 20 mark except for on cold mornings at start up it'll be in the middle. If i come close to killing it it'll drop down to nothing and the check gauge light will come on and go away when I put some load to the engine.

 

Acceptable oil pressure is 10 psi per thousand engine rpms. The oil pump is engine driven so the real oil pressure rises and falls in step with the engine rpms. Early TJ oil pressure gauges show the true oil pressure complete with its ups and downs. Later TJs around 2003 had their oil pressure gauges reprogrammed to stay mid-scale no matter what the real oil pressure is. The factory changed it because most new TJ buyers had never had a real oil pressure gauge before and too many refused to believe the oil pressure was supposed to vary up and down. Dealers were getting buried in complaints about the oil pressure dropping at low or idle engine rpms, they asked the factory to reprogram it for that reason.

 

..Sounds like Jeep adopted Ford's idiot oil gauge (idiot light shaped like a gauge) philosophy to con/mislead less than knowledgeable consumers...
Does anyone know if some functionality can be returned to the gauge by installing a pressure sensor as on some older Fords? ... or is the "gauge" entirely computer driven?

Enjoy!