Actually, 5W and 0W are the same by the SAE Standard for the
low-temperature viscosity rating; only the low temperature cranking
effort is slightly lower for the 0W as opposed to the 5W.
So, you'll have no lubrication issues using a 5W-20.
Here's the SAE J300 chart for comparison purposes...
SAE Low Temp. Low Temp. Kin. Visc-cSt
Grade Cranking Pumping Min. Max
0W 6,200 @ -35 60,000 @ -40 3.8
5W 6,600 @ -30 60,000 @ -35 3.8
10W 7,000 @ -25 60,000 @ -30 4.1
15W 7,000 @ -20 60,000 @ -25 5.6
20W 9,500 @ -15 60,000 @ -20 5.6
25W 13,000 @ -10 60,000 @ -15 9.3
20 5.6 9.3
30 9.3 12.5
40 12.5 16.3
40 12.5 16.3
50 16.3 21.9
60 21.9 26.1
I truncated and additional column for the high-temp high-shear viscosity
as it didn't fit well and the above seemed adequate to demonstrate the
general nature of the rating system.
The Low Temp cranking and pumping columns are in cP(oise) @ the listed
temperatures in C. The kinematic viscosities are in cSt(okes).
It's the low temperature lubrication before the engine is warm that the
W rating is for anyway as once it gets to operating temperature the
other end of the spectrum is the key item.
Upshot is, go w/ the 5W-x and you'll be fine (and as someone else noted,
if you take it to the dealer for service in all likelihood that's what
they'll use, anyway... :) )
Some people do care about compatibility issues etc because additives
vary with viscosity. Running straight weight oil is a relic from the
long ago past. A car engine isn't some industrial gear box that is
always in the same temperature range. Using a lubricant that changes
viscosity as required is quite sensible and good engineering. This is
especially true where using a heavy straight weight oil would make the
vehicle unusable for half the year because you could never start it.
Actually, that could be a major benefit under that scenario since if it
isn't running at least it isn't running cold unlubricated because the
oil is too viscous at low temperature to get to the upper parts of the
engine. (wry :) )
This is particularly important w/ OHV engines...
On Mon, 05 Oct 2009 16:30:21 -0400, email@example.com wrote:
It was an accurate statement. He said it was "especially true where
using a heavy straight weight oil would make the
vehicle unusable for half the year because you could never start it."
That's in about 1/2 to 2/3 of the world for 1/4 to 1/2 the time.
My only point is you shouldn't beat someone up about their experience
on an international newsgroup based on your experience in the arctic.
The other thing I would say is just about any oil will work in most
engines for the life most people expect out of their car. Most cars
are junked long before the engine blows up. In the little latitudes I
care more about what the oil pressure is on a hot day than what the
cold cranking characteristics are. Multi viscosity oils don't seem to
hold up as long. 10w30 is 10 weight oil with a magic ingredient that
makes it 30 when it gets hot ... until that ingredient stops working.
Then it is just 10 weight or less
On Tue, 06 Oct 2009 10:34:48 -0400, firstname.lastname@example.org wrote:
Long chain polymer VI improvers coil up and thicken the oil somewhat
when hot. (not thicher than when cold, but thicher than they would be
without them) If and when these long-chain polymers shear, they loose
their ability to stabilize the viscosity.
This is about half of how multigrade oils work. At the other end,
pour point depressants keep the oil from thickening as much when cold,
and friction modifiers reduce the cold strat friction, reducing the
cranking power required to start the cold engine (which is part of the
SAE test sequence for the XW part of the rating - so in reality a
10W30 oil is closer to a 15 weight oil with addatives - or even a 20,
in the "real world"
On Tue, 06 Oct 2009 10:15:09 -0400, email@example.com wrote:
I'll "kinda" agree with you.
Even here in Cenral Ontario, the "interlaken: region " of the "great
white north" it gets hot enough in the summer that I do not trust an
Xw20 or Xw30 conventional oil for highway use.
My summer oil in the 2.5 Mystique is 10W40 - changed before 6000 km
(usually before 5000).
The 3.0 liter Chrysler (mitsubishi) that preceded it used 10W40 in the
winter and 20W50 in the summer for over 240,000 km an 18 years, as did
both 3.0 liter Aerostars.
My 2003 PT Cruiser runs 5W30 full synthetic Mannheim oil year round.
3 changes a year - no more than 4 months on a change which varies from
5-8000 km. If I hit 8000 km before 4 months (happens once in a while)
it gets changed.
Today's "quality" multigrades do not suffer from serious shear
degredation of viscosity in normal use with 5000km change intervals.
With 10,000km change intervals (particularly summer highway driving
with a load) I'd be worrying.
blah blah blah. did you notice that the straight 30 still has the same
sg or sh rating as your wonderful multi-vis? Also, multiple hundreds of
thousands of miles on my '02, '03 and '04 vehicles with no ill effect.
the multi-vis thing is a scam for gas mileage ratings only.
Tell the poor sucker in Moose Jaw Sak or Billings Montana that when he
tries to start his car New Years Eve with 30 weight oil in it.
Or even in London Ontario, Detroit Michigan, or Oshkosh Wisconsin.
Now the 0W20 and 5W50???
Yup - fuel mileage ratings. Pure and simple.
Actually multi-viscosity has nothing to do with gas mileage, it has to
do with excessive engine wear at start-up. At operating temperature the
5W30 and the 30 have the same viscosity.
In tropical climates you're probably fine with straight 30 in a vehicle
that specifies 5W30, you'll get slightly more engine wear at start-up
but not enough to worry about.
OH, and BTW, i live in zone 5, granted not the coldest place in the US,
but the oil has nothing to do with the ability to start the engine. I
ran straight 50 in a 400 ford for years due to consumption issues and
never had a bit of problem with it either. It also was used to push
snow, so yes, it was used in the winter.
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