I have been using Mobil 1 - 0W-40 oil for all of my oil changes but I am interested in increasing the bottom end a bit since I don't drive the car in the winter and I want additional start-up protection.

My thinking is that with a slightly higher low end viscosity, say 5W, there will be a little more residual oil left on all of the moving parts during startup.

Please enlighten me here. I was always under the impression that 0W is roughly equivalent to the viscosity of water as a reference. Am I all wet with this? If that is the case, upon shut down, I would expect much of the beneficial effects of the oil to drain off of the components that require them during startup! This is why I was thinking of going to a 5W. I feel it will cling better between startups and thus lower the wear rate.

With all of this said, I was looking on the Mobil site and they have the following oils in the Mobil One line:

• Mobil 1 0W-30
• Mobil 1 0W-40
• Mobil 1 5W-20
• Mobil 1 5W-30
• Mobil 1 10W-30
• Mobil 1 Truck and SUV 5W-40

If I were to choose, I would go for the Truck and SUV 5W-40 oil. Just because it markets the oil as "Truck and SUV" doesn't mean squat to me. It is 5W-40 oil. As long as it meets API SL/SJ requirements, I feel I am good to go.

I would appreciate intelligent thoughts on this subject. Please share............

 

http://www.mobiloil.com/USA-English/...s/Mobil_1.aspx

The "Truck and SUV" Mobil One 5W-40 oil can be found here.........

http://www.mobiloil.com/USA-English/...SUV_5W-40.aspx

 

I like the idea of the 5w-40 too. It seems like a good choice in warm weather climates like CA. I am sure that we will hear a kinds of opinions.

 

Mobil 1 SL, lots of antiwear (Zinc) and detergent (Ca).

 

Less Zinc, boron, Calcium, Moly.
It MAY have some improved base oils that partially compensate for the reduced additives found on elemental analysis.

 

Note the 5w40 truck & SUV has more Zn and Ca than current Mobil 1 0w40. The 5w40 also has lots of Magnesium which is a good antiwear and detergent additive, but it might have a slight tendency to foul plugs if an engine burns oil.

 

Redline may be the best oil generally available. It is made from expensive ester base oil and has LOTS of zinc and moly antiwear/ friction reducer additive.

Redline 10W-40Lab:
Blackstone Laboratories
Sample Date: April 19, 2005..

Molybdenum 592
Boron 13
Silicon 14
Sodium 21
Calcium 2852
Magnesium 7
Phosphorus 1355
Zinc 1360

Sus Viscosity @210F 75.3 (Should be 65-76)
Flashpoint (F) 420 (Should be >375)

It costs about $8/qt. vs. $4/qt. for Mobil 1 truck and SUV.

I got this info from the forums at Bobistheoilguy.com.

 

Don't forget that flow relates to how quickly new oil
gets to the parts at startup too. Whatever remains
on a part from last night may be scrubbed off quickly,
so you probably want what Porsche tells you you want.
The idea of Mobil-1 truck oils is excellent if you can get
them in the correct viscosity, because some of the
beneficial additives in oil have been diminished recently
because of emissions concerns, not performance, so
other oils, like motorcycle or truck oils are freer to have
more good stuff.
Molybdenum is one excellent startup friction-fighter,
but is in few oils. In fact it causes loss of grip in motorcycle
wet clutches and starter clutches. Redline oil is among
those that do have it.
So look to additives, not viscosity change, for
startup/wear protection.
Lastly, viscosity does not equate with retention/binding.
Even if an oil is as thin as water (and I don't believe 0-weight
oil is that thin), the film retention (how much of a film
stays on a part), is very different. Oil won't dry off, and it's
affinity to adhere to metal surfaces is better and different
than water. You may be worrying too much.
Joe

 

Oh, another game you might consider is that additives are
arithmetic, in that if you have 4 qts of zero-additive oil
mixed with 4 qts of X ppm of an additive, you end up with
8 qts with X/2 ppm of the additive, which may provide
much of the benefits of the additive. However, viscosity
is not linear, it's logarithmic, which means that if you mix
two viscosity oils, the result will be much closer to the
viscosity of the thinner oil than the thicker. Therfore, if
you put in, say 3 qts of 0-40 Mobil-1, and 5 qts of 5-40
truck and SUV, or even 2 and 6, you gain lots of the
additives, but keep the viscosity very close to 0-40 as
Porsche recommends, and as will be best for startup.
I think I'll start doing that myself.
Good thread, and thanks for the link on truck/SUV
additives.
Joe