Using 5w20 Oil

[bg]

Subaru normally recommends using 5w30 oil. See any objections in trying
5w20...for possibly better fuel milage?

TIA...bgin

 

[y_p_w]

Subaru normally recommends using 5w30 oil. See any objections in trying
5w20...for possibly better fuel milage?

TIA...bgin

Don't do it. I'd guess a Subaru would likely survive through the
warranty period with a 5W-20 oil, but what would be the long-term
consequences?

I've heard that Mobil 1 5W-30 is pretty close to being a 5W-20 oil.

 

[Jim Stewart]

Don't do it. I'd guess a Subaru would likely survive through the
warranty period with a 5W-20 oil, but what would be the long-term
consequences?

I've heard that Mobil 1 5W-30 is pretty close to being a 5W-20 oil.

I agree. I run Mobil 1 10W-30 because it significantly
reduces valve clatter on startup.

 

[Rockin Ronnie]

Subaru normally recommends using 5w30 oil. See any objections in trying
5w20...for possibly better fuel milage?

TIA...bgin

I would go with the manufacturer's recommendations. However I run 5W-20
in a Ford Focus ZX-3 and have noticed good fuel economy. BTW Ford (of
America) recommends 5W-20 for it's ZTEC engines.

 

[name]

Subaru normally recommends using 5w30 oil. See any objections in trying
5w20...for possibly better fuel milage?

Subarus run lower coolant temperatures, so 5w20 might operate thicker
than 5w30 in another car. You could always do an experiment, and tell
us the results.

 

[al gu]

Subaru normally recommends using 5w30 oil. See any objections in trying
5w20...for possibly better fuel milage?

TIA...bgin

It will do nothing for fuel milage
it will protect your bearings less though

 

[Edward Hayes]

Dumb idea to even consider it with present engine replacement/rebuilding
cost

 

[Mike]

I asked SOA via e-mail this question a few months ago. Their reply was
the generic "refer to you owners manual" for recommended oil
viscosity. In other words "don't do it."

Mike

 

[y_p_w]

It will do nothing for fuel milage

I disagree. Ford, Mazda, and Honda seem to believe that 5W-20 improves
fuel economy. Ford even has a list of 5W-20 approved vehicles going
back to before they started using it.

it will protect your bearings less though

That I do agree with. There seem to be the macho Ford F-150 truck
owners who refuse to use the recommended 5W-20 oil.

My biggest problem would be going counter to the manufacturer's
recommendations. Ford and Honda have extensively tested their
vehicles for use with 5W-20 oil and Subaru hasn't (or hasn't made
it public).

 

[Jkpoulos7]

My biggest problem would be going counter to the manufacturer's

recommendations. Ford and Honda have extensively tested their
vehicles for use with 5W-20 oil and Subaru hasn't (or hasn't made
it public).

Subaru "prefers" 5w30 but if you read the manual 20w50 is preferred for towing
and in 100F plus temps. I imagine that using any of the listed oils at a given
temp range will not result in damage. With 10w30 my 2.5 04 OBW is quieter and
mpg is the same. Since 10w30 is listed as suitable for NJ temps in spring in
summer I'm not worried about engine damage especially when using syn blend oil.

 

[Carl 1 Lucky Texan]

I think the CAFE rules have created a somewhat artificial impetus for
auto monufacturers to recommend extremely low viscosity oils to get an
xtra .5 mpg during govt. testing. I've heard (anyone confirm?) that many
models sold overseas with identical drivtrains to the US versions have
manuals listing higher weight oils.

Carl
1 Lucky Texan

I asked SOA via e-mail this question a few months ago. Their reply was
the generic "refer to you owners manual" for recommended oil
viscosity. In other words "don't do it."

Mike

 

[Jack]

Why would you do this. In 5w30 the 5 refers to viscosity of the oil
at cold temperatures (yes, I know that is not precisely true, but
close enough for the arguement) while the 30 refers to viscosity at
high tempuratures. Before I would go with a 5w20, I would investigate
a 0w30. That might actually be of more benefit, but only slight.

 

[oothlagre]

It would depend on the climate you live in. If it doesn't get really hot for
long periods in the summer, then it should be fine.

I run 5-30 in the winter and 10-40 in the summer. Thinner oil in the winter
will help it start easier and the oil is thinner when starting so you get
better lubrication. A thicker oil in the summer will be thicker at higher
temperatures and will give better lubrication.

Subaru engines have a lower operating temperatures than some. I am
especially amazed at how well mine dissipates heat with such a puny
radiator. I had an old AMC 360 V8 in my old Jeep that ran 240 most of the
time. I didn't run anything thinner than 10w40 in that beast. In the summer
I ran 20w50.

Henry

As for fuel economy, I seriously doubt you can measure the difference
between 5w30 and 5w20.

 

[Rick Courtright]

My biggest problem would be going counter to the manufacturer's
recommendations. Ford and Honda have extensively tested their
vehicles for use with 5W-20 oil and Subaru hasn't (or hasn't made
it public).

Agreed, and I'd be especially careful during the warranty period. And,
regardless of what Ford, Mazda or Honda recommend, we're talking Subaru.
IF (and that's ONLY if) one has an oil-related warranty problem, telling
the Subaru dealer "Well, my Honda book says it's ok" isn't likely to get
one too far.

Since I live in a warm climate--SoCal near the desert--the cold starting
part of the equation's not as important to me as hi-temp protection.
I've seen virtually no difference between 10W-30 and 10W-40 or 15W-40 as
to fuel economy, but a major difference in oil pressure, which makes me
a bit nervous. So I doubt any fuel economy increase from dropping to a
20 weight would be significant vis a vis the risk of engine wear if it's
not mfr approved. Naturally YMMV depending on climate and other factors.

Rick

 

[y_p_w]

y_p_w wrote:




Agreed, and I'd be especially careful during the warranty period. And,
regardless of what Ford, Mazda or Honda recommend, we're talking Subaru.
IF (and that's ONLY if) one has an oil-related warranty problem, telling
the Subaru dealer "Well, my Honda book says it's ok" isn't likely to get
one too far.

Since I live in a warm climate--SoCal near the desert--the cold starting
part of the equation's not as important to me as hi-temp protection.
I've seen virtually no difference between 10W-30 and 10W-40 or 15W-40 as
to fuel economy, but a major difference in oil pressure, which makes me
a bit nervous. So I doubt any fuel economy increase from dropping to a
20 weight would be significant vis a vis the risk of engine wear if it's
not mfr approved. Naturally YMMV depending on climate and other factors.

As an aside, I recall that Mobil 1 first came out in a 5W-20 weight.
Mobil's rationale was that it could provide protection that was at
least equivalent to the 10W-30 and 10W-40 motor oils available in the
early 80's. The alleged benefits were better fuel economy as well as
better cold starts.

Of course Mobil had a hard time convincing people to run counter to
the manufacturers' recommendations. They used to recommend 1 year
or 25K mile oil changes (with regular filter changes) in addition
to the oddball (at the time) 5W-20 oil weight.

 

[Rick Courtright]

Of course Mobil had a hard time convincing people to run counter to
the manufacturers' recommendations. They used to recommend 1 year
or 25K mile oil changes (with regular filter changes) in addition

IIRC a major reason for consumer reticence lay in the fact manufacturers
made it pretty clear if you didn't follow their recommendations, they
did they not have to (nor would they) honor warranty claims. Lessee,
now: I use the wrong weight oil in my engine, the transmission goes out
and it's not covered? It would be a hard sell to get ME to change...

Rick

 

[y_p_w]

y_p_w wrote:




IIRC a major reason for consumer reticence lay in the fact manufacturers
made it pretty clear if you didn't follow their recommendations, they
did they not have to (nor would they) honor warranty claims. Lessee,
now: I use the wrong weight oil in my engine, the transmission goes out
and it's not covered? It would be a hard sell to get ME to change...

Well - **technically and legally** the responsibility for proving
that improper maintenance led to a failure lies with the manufacturer.
Practically speaking, the dealer/manufacturer might not go through
the trouble if they think they have the owner with his pants down
(i.e. "you used what?").

From what I understand about the early Mobil 1 was that they had a
host of problems with seals leaking, but otherwise cars ran
extremely well. I remember an '84 Mercedes-Benz approved oils
list, and Mobil 1 5W-20 was on it, but only for colder ambient
temps.

 

[Mike]

Funny, at least one manufacturer I know does not recommend 10W-40.
Years ago a major oil company had a bad lot of 10W-40 get out, seems
it went to something like 10W-20 real quick & killed a few engines.
5W-30 in the winter & 10W-30 in the summer for me.

Oh, also a few years back GM had a recall on cars to have the oil
changed. Seems they left the factory with 10W-30 & the recall was to
change them to 5W-30 because that's what they ran for the EPA tests.

Mike
'01 OBW

 

[y_p_w]

Funny, at least one manufacturer I know does not recommend 10W-40.
Years ago a major oil company had a bad lot of 10W-40 get out, seems
it went to something like 10W-20 real quick & killed a few engines.
5W-30 in the winter & 10W-30 in the summer for me.

I can't think of any current manufacturer that says conventional
10W-40 is OK for "standard" use in certain climates, except Subaru.
The vast majority of US owner's manuals specify 5W-30 or 10W-30
as the preferred weight. 5W-20 is the preferred weight for most
recent Honda/Ford/Madza engines. Some German cars come with
recommendations for 5W-40 or 0W-40 synthetics, but those come with
a specific oil (Mobil 1, etc) in mind.

My guess is that most engines can tolerate a wide range of oil
weights without any kind of major catastrophe occuring for a long
time. It's been established that virtually identical engines
can come with different recommendations in the US compared to
Europe or Asia. Whether or not 5W-20 oils can reduce the long-
term life of engines hasn't been established. However - I have
heard reports that oil analyses from Fords/Hondas running 5W-20
oil have shown metal wear rates similar to running 5W-30/10W-30.

Oh, also a few years back GM had a recall on cars to have the oil
changed. Seems they left the factory with 10W-30 & the recall was to
change them to 5W-30 because that's what they ran for the EPA tests.

Seems about right. Never underestimate the power of a recall
campaign to show that the automaker "cares".

 

[BG]

Well, I went ahead and put Motorcraft 5w20 Premium Synthetic Blend
motor oil into my '00 OBW and to thicken it a bit added 1qt. of Mobil
1 T&SUV 5w40. After 1298 miles with this mix I got no change in gas
mileage. Acceleration seems to be better. Once the car is up to
temperature, she sounds the same...maybe even a little quieter, but
thats really a subjective motion. The infamous Subaru cold start
ticking is still there, no better or worse sounding, but takes longer
to dissipate which bothered me. So yesterday I drained a quart out
and added Chevron Supreme 10w30 to try and thicken it a bit more.
Seems to have worked, the cold start ticking is still there but
dissipates a whole lot sooner.

bgin