Full Size Jeep Network

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.

But we do care......and keeps us coming back for the next session

We are here for you.

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.

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.

Don't worry I've gotten the same feeling with a bunch of my posts and stuff.

I would be questioning the actual viscosity of the oils. Either Mobil 1 is lying or the other brands are lying. Something ain't right.

I also agree with candymancan--58 psi is WAY too much for a low-end torque engine. I highly doubt you're revving it to the moon; it's not a 8000+ rpm racing engine. Even if it does hit that kind of speed, it shouldn't be frequent enough to need that kind of pressure.

15w-40 Shell Rotella. High zinc
6 quarts for the AMC 360

Well i will add i went back to the F1 0-40 Valvoline oil from the cheapo 10-40 walmart oil.

And oil pressure is back to 20 psi idle HOT and 50 driving versus well 5 psi hot idle and 35-40 driving.. I knew something was up i just wasnt sure if it was the engine or oil or oil filter.

Start ups are also dead silent versus the racket the walmart oil made for a split second.

I've been using O'Reilly's brand oil, just because I have become a bit of a miser now days.

After some digging, it looks like Omni is the manufacturer, but I haven't heard much about this company or the quality of their oil.

I do get a little chatter on the first start of the day, but only for a few seconds.

I have heard Pennzoil uses wax additives, so I have always stayed away from it.

Given the option, I would use Valvoline.

10W-30 year round just for better pressure and most of my rigs burn oil lol.



Sent from my Pixel 4a (5G) using Tapatalk

Harry Dawg wrote: ↑Mon Jul 10, 2023 6:12 pm I've been using O'Reilly's brand oil, just because I have become a bit of a miser now days.

After some digging, it looks like Omni is the manufacturer, but I haven't heard much about this company or the quality of their oil.

I do get a little chatter on the first start of the day, but only for a few seconds.

I have heard Pennzoil uses wax additives, so I have always stayed away from it.

Given the option, I would use Valvoline.

10W-30 year round just for better pressure and most of my rigs burn oil lol.



Sent from my Pixel 4a (5G) using Tapatalk

Omni just repackages oil from Mobil, Exxon, and Shell. So I would assume there is some inconsistency bottle to bottle.

As for Penzoil, it used to have issues, but that was decades ago. They used high sulfur oil, and added paraffins to it. So it did get a reputation for sludge buildup. But to my knowledge, that is simple not the case anymore. Shell purchased Penzoil in 2002, and at some point after that Penzoil and Quaker-State just became repackaged Shell.

I have actually used Penzoil full Synthetic in my JKUR for the last few oil changes, and its been fine.

I've been running Mobil 1 motorcycle 10W-40 oil from Autozone. It's 4-stroke, synthetic, has almost as much zinc as the Valvoline VR-1, and is the same price as the name brand 10W-40 conventional. Seems to be doing well.

I have been running Rotella 15-40 in all my older flat tapped engines for years now. AMC 360cid, 4.0L and an Opel 1.9L. Walmart is usually the cheapest for it.

I'm a big fan of Rotella 15-40 and Napa gold filter for my well used 1976 401. Not a fan of synthetic or blended oils for these old iron engines. To each his own though.

Yeah I gave up on the synthetic pretty quickly. Now I'm running the Motorcraft diesel 10W-30 because it's super high zinc w/o being so thick it bogs everything down.

I like the K+N premium and the Bosch Premium filters, although I'd run Motorcraft if I could find a big one for the Buick.

sierrablue wrote: ↑Thu Jul 13, 2023 5:25 pm I've been running Mobil 1 motorcycle 10W-40 oil from Autozone. mage miniatures It's 4-stroke, synthetic, has almost as much zinc as the Valvoline VR-1, and is the same price as the name brand 10W-40 conventional. Seems to be doing well. https://piktid.com/

That's great to hear!

i exclusively use synthetic oil 20-50 due to the extreme duty i experience in phoenix year round and more so in the summer, a i also use a k&n oil filter as a primary filter , almost all filters only filter to eliminate 20 micron materials, i run an auxiliary frantz oil filter which filters oil to 2 microns and change both filters at 7500 miles, my oil analysis by blackstone shows that at that interval the oil is the same as new oil with natural contaminant levels however the dispersants and detergents added to the oil break down so i add an additive tbn booster 1 pt to 5qts and run my oil to 20,000 miles but again change the filters at 7500 and add the additive with oil analysis at 7500 , and get the oil report stating what metals and silica are in the oil, and change oil sooner if recommendations are made by blackstone labs thats what i do and get oil pressures of 20psi at idle and 45-50 at 70 mph,