bruggz351

My stock gauge and an aftermarket gauge both read off the chart...
I've used a flush additive at service time with little effect.
Apart from the gauge readings, everything else seems good..

Both gauges are tapped into the filter adapter. Is there somewhere else I can get oil pressure from for another aftermarket gauge, in case the problem is in the filter adapter.??

cheers

cropduster

My 2001 XJS with a Napa silver filter and whatever is the cheapest 10w-30 high mileage oil in it runs at a little over 50 psi at highway speeds and idles aroun 30-35 warmed up. 172k on it.

bigbadon

Factory spec is at least 13 psi at hot idle. There are more misconceptions about oil pressure than you can shake a stick at.
Mine has 4psi at idle and 25 at 2000 rpm. Oil pressure is not a function, it is an indication of resistance to flow....in other word it is used to reference engine wear.
Nascar engines have only 30 psi at 9000 rpm! The important thing is flow,if oil is getting to the top of the motor (rockers) and lifters are staying pumped up your ok. IF your pressure is low because of wear, increasing pressure,by whatever methods, will have no benefit at all.

centuryhouse

Same here with my 2000 XJ w 185,000 miles.

jj1562

I have a '96 classic, she runs 40 psi on the nose at normal driving speeds

KJamesJR

Have you replaced your oil pressure sending unit? Not sure on different year builds, but you'll probably want to look into this. The stock gauge (for my 98 at least) plugs right into the oil pressure switch/sender, not the filter adapter.

jeepcountry4x4

My 95' cherokee runs right under 60 when cold. When its warmed up going down the road, it runs at about 45. At idle it usually runs 18-25.

Sturgis_larry

My Jeep is a 1999 Cherokee with a 4.0. Is 13lb still the correct number for oil pressure at warm idle? Hoping to install a new gauge today because it is running much lower than that. Already switched the sending unit.

BlueRidgeMark

1. Specs don't change just because a year or two goes by.

2. These electric gauges are notoriously inaccurate. Before you change out your gauge, check your pressure with a mechanical gauge.


You can probably borrow a test kit from Autozone or Advance Auto - they both have free "rental" tool programs. The deal is, you "buy" the tool at full retail, use it, and take it back for a full refund. It will probably not be a new tool, but it will be functional. You can decide to keep it if you want to, and there's no problem.


OR, buy an inexpensive mechanical gauge and hook it up temporarily to see what you really have, and go from there. I did that a while back. $16 for a Bosch at Pep Boys and it took me all of ten minutes to hook it up, verify my readings at various RPMs, take it out, put back the original sending unit, and close things up.

Sturgis_larry

The gauge I bought to install is mechanical. Unfortunately it is only 6 outside at noon today and I do not have a garage. The gauge may have to wait a day or two. But thanks for the reply.

bigbadon

Don't want to hijack this thread BUT the 4.0 on my GC runs 4-5 at hot idle and about 25 going down the road......been that way forever. No issues,runs fine.

BlueRidgeMark

I hear you. It's about 10 where I am. 15 minutes work outside, 20 minutes inside thawing out!

Ralph77

'00 4.0. Napa oil, 5w30 winter, 10w30 summer, Napa gold filter 1085. Start up 45lbs. When running about the same. Very hot idle about 22lbs. Never checked with an external gauge. Probably should at some point.

MtnGoat

Old school rule of thumb, 10PSI for every 1000RPM

Hmwspade01

i know its an old thread but what weight oil do you run. Mine sits aboyt 40 at idle and 65 to 75 driving. 10w30 is what im runnin