Different brand oil and much better oil pressure from it

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Different brand oil and much better oil pressure from it

Post by Phils67 »

Today I was at the Home Depot and figured I'd grab a few big jugs of oil to change the Gladiator and the XJ (both with a 4.0). Normally I use Mobil 1synthetic 10w30 with a Mopar MO-090 filter which I buy by the 12pks. My Gladiators 4.0 idled around 43 psi and my XJs usually idled really low around 18psi. Today I bought Pennzoil Platinum full synthetic 10w30 since they didn't have Mobil 1 and my truck is now idling at 58psi and my XJ at 40psi. 3 years owning that XJ I've never had oil readings like that, and ive used Castrol as a substitute in the past a couple times. Think I'll stick with this brand going forward. Happy with the pressures as now the XJ is more where it should have been all along. I just wanted to tell someone this because it makes me happy and everyone I know around here could care less about my jeeping and shop antics.
1967 Gladiator J2000, 1998 4.0L OBD2, T18, D20 twin sticks, D44HD/D60, Detroit lockers, 3.73s, 4wheel disc brake, FSSR, Dakota digital, etc.
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Re: Different brand oil and much better oil pressure from it

Post by devildog80 »

But we do care......and keeps us coming back for the next session :)
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'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
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Re: Different brand oil and much better oil pressure from it

Post by will e »

We are here for you. :)
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Re: Different brand oil and much better oil pressure from it

Post by weeegoneeer »

Somewhat related, I've been using amsoil z-rod 10w40 and after long highway runs my oil pressure would get scary low at idle. Dropped some napa 10w40 dino oil in it before a 1,000 mile trek back home and highway/idle pressures are much improved. One would think the oil rating describes actual viscosity at differing temps but there's something else at play here.
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Re: Different brand oil and much better oil pressure from it

Post by candymancan »

I will throw something out there.. that high idle oil pressure is wasted oil pressure that bleeds offand can actually cause more lubrication issues than good. Just an fyi. 58 at idle is way too high in my opinion especially if thats a HOT idle in drive

With my continious rear main seal leak.. I cant try other oils as its a waste of money.. but id like to try oils other than the walmart special. Maybe if the penzoil is on sale lol.

But i am curious now because i used to put castrol gtx or valvoline blend in ny 90. And my oil pressure was like 20 at idle after highway driving and 50-60 driving

And with walmart oil itll go below 10 sometimes which i hate and 45-50 driving.. . I didnt think much about brands of oil and viscosity at temps.

I know project farm on youtube tests oils for this. Ill have to look at his vids and see what he came up with.
1998 Jeep Grand Cherokee 5.9L Limited 215k
1998 Jeep Grand Cherokee 4.0 I6 laredo 394k
1990 Jeep Grand Wagoneer 151k
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