AO

Yes... another oil use thread, but since people are now starting to move away from some of the old standard oil because of changes in their formulations, I think it's important to post our results.

When i first got my car I tried Mobil1 10W-40 (I think) and did not like the oil pressure reading I was getting. It seemed very low. So I switched back to my old standby, Castrol GTX 10W-40, and have been running it for the past year and a half. I don't know what the PO used.

Now I have learned a lot credited to Doug Hilary(sp?)'s extremely informative posts. I also have learned that oil pressure does not = oil flow, but since we don't have a flow meter, we use pressure as a gage of flow.

2 days ago, I decided it was time to make the switch to Shell Rotella T Synthetic 5W-40. I was expecting lower oil pressure similar to what I had experience with Mobil1, but to my surprise, oil pressure seemed fine. Upon initial start-up, oil pressure read 4.5bar. After 20 minutes of running, oil pressure at idle was just shy of 1 bar and at 3k RPM was about 4 bar. The Mobil1 IIRC was less that 3bar at 3k. Maybe the Mobil1 was fine, but I remember someone telling me that I should look for 1bar above RPM level. That's what I have now, so that makes me happy.

I'll monitor the oil when we head down for SITM and see if it degrades at all during the trip and will report back.

As for initial impressions, I'm happy.

Oh yeah, it costs <$17/gal. at Wally World.

hacker-pschorr

What Andrew doesn't know is while he was in Green Bay, we dumped out his containers of Rotella in exchange for Folgers Crystals.

AO

I thought that was my Royal Purple Gear oil that you did that too...

RyanPerrella

Andrew,

I think you should look for 2bar oil pressure at idle when warm. mine is between 1.5-2.0 and i would like to see it at 2. If your only at 1.0 bar I would not be happy with that. But I could be wrong. I thought 2 is ideal at idle.

AO

With a thicker oil, yes. But a thinner oil should flow better (assuming there is pressure which there is). Think about this: If you suck with the same amount of force through a straw, which will flow better, a tripple thick shake or a coke?

hacker-pschorr

Assuming his gauge is accurate at idle, he's seeing 14+psi of oil pressure at idle. That is plenty, I wouldn't worry about it.

928ntslow

Depends on what orifice you're using.

I was thinking of doing the switcharooni as well, but couldn't find it at my local Target. Guess I will keep looking. The Mobil One is great, but justifying the cost is....well....no longer justifiable!

BTW Andrew...What the hell does "CLECK" mean?

ew928

AO,
Got a pic of your oil pressure gauge?
My Mobil 1 0-40 pegs the pressure gauge at cold. Takes about 10-15 minutes to warm the oil up. Then will idle at around 2 on my 88's gauge.
Needs around 2200 revs before the pressure gauge gets pegged again.
Are the numbers = bars on the earlier pod gauge. I've read the owner's manual ages ago and forgotten all the useful stuff.
Been only up to 80 around here so no real Texas hot weather testing.

Wouldn't mind a nice thick chocolate shake now.
(As long as it's not being frothed in my oil pan)

AO

I have no idea what you're talking about...

I'll get some pics on the way home today.

Tony

....and soaked his hands in Palmolive!

FlyingDog

Damn, it used to be $12 and last time I bought it, it was $14. Still cheaper than M1 5qt bottle at $23-25, but getting closer.
IIRC, M1 0w40 does not meet Porsche's minimum HTHS spec for the 928 engine.

hupp

Someone posted a Porsche technical publication in another thread that advised that 0w-40 or 5w-40 grades are to be used "retroactively" in all 4, 6 and 8 cylinder Porsche engines. This publication lists all of the approved brands also -- everything was 0w40 or 5w40. AND, based on soe other reading, Doug Hillary had some good stuff to say about Rotella.

I was sold and I've got Rotella 5w-40 in my '79. Solid 2 bar at hot idle and 4.5 bar at 2000rpm 5bar at 3000rpm.

Bill Ball

M1 0W40
HTHS Viscosity, mPaˇs @ 150ēC ASTM D 4683 = 3.6
Porsche spec is >3.5, IIRC.

just put in the new M1 10W40 for high mileage cars with an HTHS of 4.06.

FlyingDog

Cool, thanks. I knew it was close, but thought it was just under, not just over.

ew928

Matt, I'll keep the motor under 4800 revs.
That make you feel better.

Doug Hillary didn't say anything bad about the new Porsche recommended M1 0-40 fill.
But then Porsche is in the business of selling motors. If they have any 5 liter V8's left.