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2012 5.7 L Oil Pressure with Mobile 1

21K views 26 replies 13 participants last post by  comnjeep 
#1 ·
I just sold my 1999 GC and got a 2012; it has ~1k miles, and this weekend I drained the convention oil and put in 7.5 qt. of mobile 1 with a Purolator filter.

I didn't look at the oil pressure before the change, but after this is what I get now.

Wanting to know what others get (it seems low to me).

idle: 34 psi
freeway: 52 psi
oil temp: 200 F
coolant: 210 F
Outside: 68 F

Thanks.
Robert
 
#5 ·
The manual does say 7. I will put in 7, drive off the ramps and let it idle for a few. After turning it off and letting it sit for 20-30 mins it'll read below the hashed area, a little above add. I add another .5qts and check it the next morning and its 3/4 or more to the top of the hash area.

Changed mine 3 times so far and that's been the case each time.
 
#11 ·
I went to M1 at about the same time (~2500 miles) in my Hemi. I just passed 41k in my truck.

I've noticed that the pressure seems low (in the same ranges as yours), but this also is the first new car I've ever owned, leading me to believe that this is the pressure that it is supposed to be running at.

I tow/haul a bit, so I change the oil every 8k miles or so. I pay someone to actually change it, but use the M1 and M1 filter. Further, I stay with 7Q; not more. (Man this thing takes a ton of oil...) Check it immediately after the oil change, looking for the level on the dipstick, should be about in the middle.

I wait till the next day or so, and check again. Then - after some miles and when I remember, I check again.

In general - it is not good to run too much oil in any engine. I therefore am very hesitant to add oil above and beyond the 7Q in my Hemi.

Next time I am in the truck I will look at the pressure at a stop light/sign after warming up and post up for you.
 
#15 ·
In general - it is not good to run too much oil in any engine. I therefore am very hesitant to add oil above and beyond the 7Q in my Hemi..
Yes I agree, and I also agree with the person that said it's not easy to get an actual reading from the dipstick.

I read a few posts (in my search to find out why I don't have a door in the hole in the plastic "air dam thing" under my engine) that said that they needed to put in 7.5 vs. 7.0 qt to get a full reading; so that's what I did when the dip stick reading was not full at 7 qt.

I plan to just put in 7 qt and then remember where "full" is on the stick, then add to there as necessary.

BTW, does anyone have a door on the hole on the dam thing under their engine, or is it just a hole that looks like there should be a door/cover?

Robert
 
#12 ·
34 at idle when warm is fine. My 6.1 and my 426 both sat around 28-30 when warm. According to the service manual, anything above 4psi(!) is fine.
 
#14 ·
I get 20 at idle and 49 hwy on my 2005 hemi
 
#19 ·
From what I understand, the door "cover" is there for the V6 guys, but the door "cover" is not there for us Hemi guys. I too wouldn't mind adding the door cover.
 
#20 · (Edited)
Is one of the differences between a gear type and a georotor pump. Gear type is almost linear vs rpm until it hits relief, georotor varies very little. As for pressure, the old adage of 10 psi per 1000 rpm is pretty good & is a function of bearing area.

Been years since I had a Jag but still watch for 40 psi at 3,000 rpm.

That said I remember seeing somewhere that the Purolator Gold was abetter filter than most and slightly more restrictive. Coupled with the lower average viscosity of Mobil-1 might result in a lower pressure than expected. However 30+ at idle and 50+ on the road sounds just fine to me.


Back in my racing daze I always ran my FI SBC a quart over but also had a 7 quart trap door oil pan all to keep from starving on a hard high rev corner.
 
#21 ·
I have been putting synthetic oil in my cars and motorcycles for years. In each case when I switched from dino oil to synthetic oil I noticed that the oil pressure ran lower at all RPM's.

As PADGETT said it's probably because of the lower viscosity and that synthetic oil is more "slippery" so it's easier to push through the engine which results in lower oil pressure.

That being said, I have never had a problem my cars or motorcycles because of the lower oil pressure.

Just my two cents. :).
 
#23 · (Edited)
MSR, welcome to the board and congrats on your rig. Your vitals look good across the spectrum.

IME in both vehicles and boats with V8's, another half quart of oil seems to be the norm, which generally tops off the new filter as added capacity to the block.

^nice work on the flap door comnjeep.
 
#24 ·
I will second moosehead's comments: your vitals look OK.
While warm, with M1....

At idle: ~30psi
At a stop sign: ~30psi
At 35MPH: ~48-50psi
at 'highway speed': ~50-55psi

I wouldn't be too concerned with your vitals...

R
 
#25 ·
Istarted this thread about 26 months ago, my GC now has 26777 miles, about 1kper month.

SoI thought I’d recheck my oil pressure, and it’s essentially identical to the 1kmiles readings:

Then Now
idle: 34 psi 34 psi
freeway: 52psi 52 psi
oil temp: 200F 203 F
coolant: 210F 212 F
Outside: 68 F 69 F

The oil was changed at dealer with synthetic, about 3k miles ago. Not sure what kind of synthetic, maybe Pennzoil.

Robert
 
#26 ·
Istarted this thread about 26 months ago, my GC now has 26777 miles, about 1kper month.

SoI thought I’d recheck my oil pressure, and it’s essentially identical to the 1kmiles readings:

Then Now
idle: 34 psi 34 psi
freeway: 52psi 52 psi
oil temp: 200F 203 F
coolant: 210F 212 F
Outside: 68 F 69 F

The oil was changed at dealer with synthetic, about 3k miles ago. Not sure what kind of synthetic, maybe Pennzoil.

Robert
The oil pressure also varies 30 ish to 90+ ish depending on rpm, throttle, crankcase vent/vac, oil age etc...
 
#27 ·
"synthetic" from a oil change place is not really synthetic.

Just look at amsoil OE versus signature series. Both say synthetic on the label, one says 100% synthetic..!! What the! Oh, and one is 5$/qt, the other 10. Don't get me wrong, they're both good oil, but one is better.
 
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