4.0 oil pressure - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 11-07-2012, 04:16 PM   #1
WVU Mountainman's Avatar
Join Date: Jun 2012
Posts: 979
WVU Mountainman is on a distinguished road
4.0 oil pressure

My oil pressure is at 20 once warm at idle. While driving it goes as high as 50. Is this normal for a 4.0. Automatic transmission if it matters.
WVU Mountainman is offline   Quote
Old 11-07-2012, 04:25 PM   #2
General Confusion's Avatar
Join Date: May 2012
Location: Waltham Abbey, England
Posts: 242
General Confusion is on a distinguished road
Seems OK to me

Too Old to Die Young!

99 TJ. 2" Old Man Emu Suspension Lift. 1.5" Body Lift. 1" Motor Lift
Warn Rock Crawler Front & Rear Bumpers. Come-Up 9500i Winch.
31 x 10.5 x 15 BFG Mud Terrains, JKS Disconnects and some other stuff.
General Confusion is offline   Quote
Old 11-07-2012, 04:29 PM   #3
harleydragon's Avatar
Join Date: Jul 2012
Location: south georgia
Posts: 3,939
harleydragon is on a distinguished road
yep,nothing wrong with that
harleydragon is offline   Quote
Old 11-07-2012, 04:51 PM   #4
Knows a couple things...

WF Supporting Member
Jerry Bransford's Avatar
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 42,224
Jerry Bransford is on a distinguished road
Yep, the engine's true oil pressure rises & falls in direct relationship to the engine RPMs. The oil pump is engine driven so as the engine revs higher, the oil pump pumps harder which raises the oil pressure.

A good rule of thumb for acceptable oil pressure is around 10 psi for ever 1000 engine RPMs.

Caution that newer TJs had their oil pressure gauges reprogrammed so they no longer show the real ups and downs of oil pressure. It was alarming too many new Jeepers who had never had a real oil pressure gauge before they bought their Jeep and didn't know how oil pressure works.
When you have a choice, buy American.
Jerry Bransford is online now   Quote
Old 11-12-2012, 08:44 PM   #5
Join Date: Nov 2012
Posts: 1
MarkR_98Sport is on a distinguished road
Thank you for asking the question. I bought my first jeep (1998 Wrangler Sport) last weekend and the oil pressure fluctuation freaked me out on the way home. But all is well. Oil, plugs and wires have been changed, distributor cap and rotor next as well as trying to tackle the exhaust manifold. Thanks to this forum I think I can handle it.
MarkR_98Sport is offline   Quote
Old 11-12-2012, 09:58 PM   #6
Join Date: Nov 2012
Location: League City, TX
Posts: 28
mnatl is on a distinguished road
same pressure here. thx for confirmation all is good!

mnatl is offline   Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 03:03 AM.

User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC
« Back

Enter your email address:

Delivered by FeedBurner