Low Oil Pressure Advice Jeep 4.0

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10,906
Location
Cincinnati, OH, USA
And, I would love to put a stroker motor in it, but I'm afraid the unibody couldn't handle it, nor the rest of the 235,000 mile drivetrain. I wouldn't hesitate to run a 15W40 HDEO like Delvac 1300, Delo LE, or Rotella T3/T4 either, I'm sure it would be fine.
 
Can't believe nobody has yet suggested starting at the beginning, like getting a second gauge (mechanical if possible) to make sure the oil pressure gauge in the vehicle is correct before doing anything?!? Since there are no noises, oil pressure may be just fine. 40 weight won't hurt. Especially in SC.
 
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2,410
Location
SD
Originally Posted by SubieRubyRoo
Can't believe nobody has yet suggested starting at the beginning, like getting a second gauge (mechanical if possible) to make sure the oil pressure gauge in the vehicle is correct before doing anything.
The OP stated that it had been verified.
 

Carnut123

Thread starter
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6
SubieRubyRoo, unfortunately I did verify the low oil pressure with a 2nd mechanical gauge which matches what the factory gauge was reporting. Thanks! Will probably give the Delo 5w40 a shot, or whatever HM 40w I can find at Wallyworld. Jumping to a 15wX scares me a bit as the engine is otherwise pretty quiet on startup and after warmed up.
 
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6,494
Location
Connecticut
I'd try Rotella T6 5w40. Like others have stated, likely the engine was run for a while with coolant in the oil, which caused cam bearing wear and the lower oil pressure at hot idle. A stroker is a great idea and the unibody and AW4 auto transmission should handle it fine.
 
Messages
10,906
Location
Cincinnati, OH, USA
Originally Posted by jeepman3071
I'd try Rotella T6 5w40. Like others have stated, likely the engine was run for a while with coolant in the oil, which caused cam bearing wear and the lower oil pressure at hot idle. A stroker is a great idea and the unibody and AW4 auto transmission should handle it fine.
Actually, my unibody is getting a little rusty in the back-not severe, but I've already replaced the rear axle with a used one due to an unfortunate accident with my son, couch cushions, and the driveshaft. Don't want to push my luck! I'm just trying to keep it going until he can get a decent job & afford something newer.
 
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6,235
Location
Kalifornia Kollective
Just trying to keep it going, 15W-40 Delo 400 would be my first stop. If that didn't get me what I wanted, GTX 20W-50 would be my second stop. Both are good oils. Just the ticket for lost bearing metal. It's rusty, just drive it until situation improves. I'll bet you'll be surprised to see how far it chugs along smile
 
Messages
13,194
Location
Maricopa Arizona
Originally Posted by SubieRubyRoo
Can't believe nobody has yet suggested starting at the beginning, like getting a second gauge (mechanical if possible) to make sure the oil pressure gauge in the vehicle is correct before doing anything?!? Since there are no noises, oil pressure may be just fine. 40 weight won't hurt. Especially in SC.
Do you read before posting?
 
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3,275
Location
On another site
Originally Posted by rrounds
South Carolina, it doesn't get that cold there. 15/40 HDEO like Rotella or DELO is what I'd use. ROD
With the new oil pump and other comments this is the strategy I'd use in SC.
 
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Messages
13,194
Location
Maricopa Arizona
Originally Posted by WyrTwister
Does any one still use STP . We used it on older cars that consumed oil . Back in the day .
Why would you use this junk? To dilute the additive package? To oxidize the oil?
 

Carnut123

Thread starter
Messages
6
Originally Posted by kaesees
I'm curious why some folks here prefer mechanical pressure gauges.
The electronic sender that sends signal to the gauge on the dash frequently go bad or read extremely high or low from the actual pressure of the engine. Using a mechanical gauge is basically a 2nd check to see if the electronic gauge on the dash is correct or just needs a new electrical sender.
 

Carnut123

Thread starter
Messages
6
Update: Changed the oil today with Delo 5w40. Hot idle seems to be holding around 10-12 PSI, so the 40w bumped up 5 or so PSI at idle which is at least enough to keep the light in the dash off. The engine is definitely more noisy on the 5w40, gonna drive it for a few days and see how everything settles out. Thanks everyone for the advice!
 
Messages
13,194
Location
Maricopa Arizona
Originally Posted by 2001XJSC
Update: Changed the oil today with Delo 5w40. Hot idle seems to be holding around 10-12 PSI, so the 40w bumped up 5 or so PSI at idle which is at least enough to keep the light in the dash off. The engine is definitely more noisy on the 5w40, gonna drive it for a few days and see how everything settles out. Thanks everyone for the advice!
Don't worry about the noise. It can be a dozen other factors not oil related.
 
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9,122
Location
Marshfield , MA
I would go with 20w50. The lower end may be a little sloppy. 20w50 will boost pressure enough to save the cam bearings which saves the rest of the valve train which is clattering ? How is the oil consumption/ compression? Is this what the AMC 258 morphed into to pass smog in the 90s? Doesn't matter, advice is generic grin2 PS. Please post results whatever you do. Driven gently it may survive a while
 
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