15W50 to quiet piston slap in 98 obw?

G

greendoom

I've got a '98 Outback Legacy with 170,000 miles on it. Being a 98 it
suffers from a loud piston slap for the first 10 minutes of running
until it reaches normal operating temperature. This noise can be very
annoying - it gets many stares especially in busy parking lots. Would
running 15W50 help this at all or would it just cause other problems
for the engine? Until this point I've been running Valvoline Max Life
5w30 since I got the car (at 159,000). Any help would be appreciated
- thanks.
 
I've got a '98 Outback Legacy with 170,000 miles on it. Being a 98 it
suffers from a loud piston slap for the first 10 minutes of running
until it reaches normal operating temperature. This noise can be very
annoying - it gets many stares especially in busy parking lots. Would
running 15W50 help this at all or would it just cause other problems
for the engine? Until this point I've been running Valvoline Max Life
5w30 since I got the car (at 159,000). Any help would be appreciated
- thanks.

try an Xw-40 first
 
I've got a '98 Outback Legacy with 170,000 miles on it. Being a 98 it
suffers from a loud piston slap for the first 10 minutes of running
until it reaches normal operating temperature. This noise can be very
annoying - it gets many stares especially in busy parking lots. Would
running 15W50 help this at all or would it just cause other problems
for the engine? Until this point I've been running Valvoline Max Life
5w30 since I got the car (at 159,000). Any help would be appreciated
- thanks.

The only 15w-50 oils that I know of are Mobil1 and Chevron synthetics,
and these can trigger leaks if gaskets are weak, so watch out. You
may want to try dino X-40, or even 20-50 instead, and if you don't live
in Minnesota, or some cold mountainous location.

I've had good results quieting piston slap with single weight oils straight
40, 50, Valvoline but these were used in V-6 GM engines in hot Southwest
locations (example: summertime Phoenix). I think Japanese engines may not
like stuff that extreme but you may try a straight 30 dino (in above
freezing
ambient temps). The thicker oils don't drain off of cylinder walls, rings,
as
fast thus help quiet piston slap at start-up.

5w-30 is very thin stuff for an engine with 170k miles.

M.J.
 
The only 15w-50 oils that I know of are Mobil1 and Chevron synthetics,
and these can trigger leaks if gaskets are weak, so watch out. You
may want to try dino X-40, or even 20-50 instead, and if you don't live
in Minnesota, or some cold mountainous location.

I've had good results quieting piston slap with single weight oils straight
40, 50, Valvoline but these were used in V-6 GM engines in hot Southwest
locations (example: summertime Phoenix). I think Japanese engines may not
like stuff that extreme but you may try a straight 30 dino (in above
freezing
ambient temps). The thicker oils don't drain off of cylinder walls, rings,
as
fast thus help quiet piston slap at start-up.

5w-30 is very thin stuff for an engine with 170k miles.

M.J.

Would 10w30 provide any noticable improvement, or would I need to go
for something more drastic?
 
As far back as I can remember, my Subaru manuals have stated
specifically, do not use 5W30 oil for sustained high speed driving and then
only when suitable low temperature conditions are present. Unless Subaru
has since changed the recommendation for '98 or newer engines, would this
not be at least a tiny concern to anybody?

My '89 GL Turbo used to have plenty of noise until it warmed up
sufficiently. I ended up having best results with is Amsoil 10W30. However
I also came up with a creative variety of oil solutions just for the
entertainment of it all, which also worked quite well to quiet the noise and
cut oil consumption. The quietest mix only had two real quarts of cheap
10W40 in it with the rest comprising generous amounts of Marvel Mystery oil,
motor honey, and various other additives to bring it up to the full mark,
and yup, they were all in there at the same time. Was fun to experiment
with the ratios, and then feel and hear the results. The death of the motor
wasn't related to oil, so no worries there. The motor died because it blew
the turbo coolant inlet line and dumped the contents of the radiator while I
was away from the car knocking on somebody's door to go to work, munched the
head gasket(s) and warped the head(s), all before I got back in and realised
something wasn't right. Was an interesting sort of catastrophic failure to
come back to the car and find; and I can laugh about it, now. The coolant
evacuated the system so quickly the temperature gauge never even rose past
75% of the way up before it stopped measuring altogether. Ended up with a
cracked radiator before the ordeal ended.

Anyway, my Subaru manuals lists several straight motor oil weights you
can use, and mentions multi-weights up to 50, but since my manual is not
specifically for your motor, I would recommend looking in your own for the
details you're seeking. Also, I've been told by mechanics that, if I want a
10W40, don't. Instead go with 10W30 or 15W40, as either of those contain
far less friction modifiers. From my understanding up to 25% of 10W40 oil
is used in just getting the viscosity to stay where it belongs. But I'm
hardly an expert, so always do your own research the best you can. (-;

~Brian
 
strchild said:
As far back as I can remember, my Subaru manuals have stated
specifically, do not use 5W30 oil for sustained high speed driving and then
only when suitable low temperature conditions are present. Unless Subaru
has since changed the recommendation for '98 or newer engines, would this
not be at least a tiny concern to anybody?

My 01 outback manual is open in front of me. They show an api service
label for SJ/SH service with teh words "energy conserving ii", and SAE
5W-30 as the general recommendation.

For "severe driving conditions" in high temp and desert areas, or for
heavy duty applications such as towing, they recommend SJ or SH
classification with SAE 30 SAE 40 10W-50 20W-40, or 20W-50.
 
KLS said:
AgreedL 15w-40 (I use either Mobil or Castrol) is a nice oil for
heavy duty engines, and it's what I use in my 98 Audi A4Q 2.8liter
5sp, now at 110k miles. The 99 Subaru Legacy OBW still eats 5w-30,
which seems ok for it.

Chevron states that Delo 400 15w-40 oil is good for engines with
shorter piston crowns. Aren't short pistons in general the reason
why many Subaru engines experience piston slap?

Here are some quotes, first from Subaru then from Chevron:

http://www.drive.subaru.com/SubaruDrive-Sum02/Piston-Cranky.htm

Through experimentation, the engineers at Subaru discovered that a slightly
barrel-shaped piston produces less friction, vibration and noise. The
engineers then focused on improving the piston skirt (the lower part of the
piston that makes contact with the cylinder wall). In a radical break with
convention, the skirt was made shorter and thinner to reduce weight.

and

http://www.chevrondelo.com/en/deloworldwide/uscanadamexico/default.asp

Applications
Chevron Delo 400 LE SAE 15W-40 is a mixed fleet motor oil recommended for
all naturally aspirated and turbocharged four-stroke diesel engines and
fourstroke gasoline engines in which the API CJ-4 grade and SAE 15W-40
viscosity grade are recommended. It is formulated for engines operating
under severe service and a wide range of climatic conditions. Chevron Delo
400 LE SAE 15W-40 is excellent for use in new advanced engines developed in
response to 2007 emissions standards and in engines equipped with features
like four-valve heads, supercharging, turbo charging, direct injection,
shorter piston crowns, higher power density, intercooling, full electronic
management of fuel and emissions systems, exhaust gas recirculation, and
exhaust particulate traps.
 
Chevron states that Delo 400 15w-40 oil is good for engines with
shorter piston crowns. Aren't short pistons in general the reason
why many Subaru engines experience piston slap?

Here are some quotes, first from Subaru then from Chevron:

http://www.drive.subaru.com/SubaruDrive-Sum02/Piston-Cranky.htm

Through experimentation, the engineers at Subaru discovered that a slightly
barrel-shaped piston produces less friction, vibration and noise. The
engineers then focused on improving the piston skirt (the lower part of the
piston that makes contact with the cylinder wall). In a radical break with
convention, the skirt was made shorter and thinner to reduce weight.

and

http://www.chevrondelo.com/en/deloworldwide/uscanadamexico/default.asp

Applications
Chevron Delo 400 LE SAE 15W-40 is a mixed fleet motor oil recommended for
all naturally aspirated and turbocharged four-stroke diesel engines and
fourstroke gasoline engines in which the API CJ-4 grade and SAE 15W-40
viscosity grade are recommended. It is formulated for engines operating
under severe service and a wide range of climatic conditions. Chevron Delo
400 LE SAE 15W-40 is excellent for use in new advanced engines developed in
response to 2007 emissions standards and in engines equipped with features
like four-valve heads, supercharging, turbo charging, direct injection,
shorter piston crowns, higher power density, intercooling, full electronic
management of fuel and emissions systems, exhaust gas recirculation, and
exhaust particulate traps.

I just bought 5 quarts of max life 10w30. If that doesn't improve
things any I'll step it up to the 15w40. My Subaru manual recommended
either 5w30 or 10w30 so I figured I'd try that first.
 
I just bought 5 quarts of max life 10w30. If that doesn't improve
things any I'll step it up to the 15w40. My Subaru manual recommended
either 5w30 or 10w30 so I figured I'd try that first.

I doubt 10w-30 is going to make any difference but
there is logic in taking a step-by-step approach and
progressing if need be. Please update us on your results.

M.J.
 
I, too have a 98 OBW. My mechanic recommends that all cars with 100K+
miles use a 20W-50W motor oil. I have been using Wal-Mart house brand
oil of that weight for some time during warm weather. Car runs just
fine. I live in Indiana, in the winter, I switch to 10W-40 for cold
weather. Engine runs without complaints. With engine wear in any car
beyond 100K miles, it is good to use the heavier weight oil to
compensate for engine wear causing looseness inside the motor. Just my
2 cents worth.
 
Sorry it took me so long to update - I've been really busy. I decided
to go for 15W40 instead of the 10w30 and noticed an improvement. The
slap goes away much quicker now - about 2 minutes instead of 10.
 
to go for 15W40 instead of the 10w30 and noticed an improvement. The
slap goes away much quicker now - about 2 minutes instead of 10.

Hi,

I've been away for a few weeks and am just getting caught up on your
"adventures." What oil filter are you using? Over the years, we've had
many discussions of "lifter noise" at startup (before piston slap became
problematic) and most posters, myself included, have found some oil
filters to be better/worse in this department. Suggest OEM filters (made
by Purolator in the US, but slightly different than what you get at the
auto parts store, though the PureOne is probably very close), followed
by Wix/NAPA Gold (same filter as far as anyone can tell, just rebadged
for NAPA.) Not to badmouth anyone's brand, but "orange" filters (and
their many rebadged clones) seem to be more problematic in this
department. A combo of 15W40 (my choice was Delo 400 for my '90 Loyale
that finally died, of a non-oil related malady, at 360k miles) w/ a bit
of filter swapping might cure most of your problem.

Good luck--sounds like you're on the way!

Rick
 
Rick Courtright said:
Hi,

I've been away for a few weeks and am just getting caught up on your
"adventures." What oil filter are you using? Over the years, we've had
many discussions of "lifter noise" at startup (before piston slap became
problematic) and most posters, myself included, have found some oil
filters to be better/worse in this department. Suggest OEM filters (made
by Purolator in the US, but slightly different than what you get at the
auto parts store, though the PureOne is probably very close), followed
by Wix/NAPA Gold (same filter as far as anyone can tell, just rebadged
for NAPA.) Not to badmouth anyone's brand, but "orange" filters (and
their many rebadged clones) seem to be more problematic in this
department. A combo of 15W40 (my choice was Delo 400 for my '90 Loyale
that finally died, of a non-oil related malady, at 360k miles) w/ a bit
of filter swapping might cure most of your problem.


Here's a nice bunch of pictures from a NASIOC thread
illustrating filter quality issue.

http://forums.nasioc.com/forums/showthread.php?t=891014&page=2

Thank's to the OP for the follow-up on his oil remedy.

I recently started using NAPA-Gold for my '00 Impreza
(previously OEM filters). The Napa Gold 1334 is
supposed to be an excellent filter composed of a mix
of synthetic (glass) and cellulose media, with outstanding
oil flow properties. I think it may be a good complement
for a thicker oil (I am using Mobil 1 15w-50 mixed with
Mobil110w-30 at 50/50 proportions), and it may be helpful
for start-up piston slap issues. Supposedly, it does not filter
the smallest of smalll particles as good as a a Purolator
PureOne, or Mobil1, but is not as restrictive as these two.
There is always a trade-of between good filtration and good
oil flow.

M.J.
 
M.J. said:
Here's a nice bunch of pictures from a NASIOC thread
illustrating filter quality issue.

http://forums.nasioc.com/forums/showthread.php?t=891014&page=2

Hi,

Looks like another guy got a cutoff wheel for his Dremel tool and has
become an oil filter expert!

Pix like this have been circulating for quite some time, and while they
DO illustrate certain cosmetic and/or structural differences, the
"appearance" of the filter belies what really happens when you fill it
w/ hot circulating oil. For example, EVERY one of these "scrapbook
analyses" makes the lowly orange Fram out to be horrid. Yeah, it's
definitely at the "cheap" end WRT to how it's built, but if it WERE as
bad as one might believe from hanging out in car forums, we'd have dead
cars strewn so thick we couldn't drive thru, around or over them! Fram
only sells about a kazillion and a half of them every year between their
Fram brand and all the house brands they make--how many actual
documented failures do we actually see? And while I don't use them
anymore, I have run them up to nearly 200k miles on other cars before my
Subie came along, w/ zero defects or complaints. And, to tell the truth,
the only reason I bothered looking for something else was that my
Subie's the ONLY car I've ever owned that's persnickety about its oil
filters!

There ARE tests to determine how well the filter actually does its job,
but even they can result in skewed results if one says it's X% efficient
and the next one's only 0.95X%--are they testing the same thing? Look up
"beta ratio" for some info on how some of these tests are done. My tiny
bit of research indicates the industry's been pretty much on its own for
setting standards and advertising test results, though some people have
been working to come up w/ some universal standards so we're always
comparing apples to apples, not sometimes oranges, bananas and grapes.

But the pix ARE nice...

Rick
 
Rick Courtright said:
Hi,

Looks like another guy got a cutoff wheel for his Dremel tool and has
become an oil filter expert!

Pix like this have been circulating for quite some time, and while they
DO illustrate certain cosmetic and/or structural differences, the
"appearance" of the filter belies what really happens when you fill it
w/ hot circulating oil. For example, EVERY one of these "scrapbook
analyses" makes the lowly orange Fram out to be horrid. Yeah, it's
definitely at the "cheap" end WRT to how it's built, but if it WERE as
bad as one might believe from hanging out in car forums, we'd have dead
cars strewn so thick we couldn't drive thru, around or over them! Fram
only sells about a kazillion and a half of them every year between their
Fram brand and all the house brands they make--how many actual
documented failures do we actually see? And while I don't use them
anymore, I have run them up to nearly 200k miles on other cars before my
Subie came along, w/ zero defects or complaints. And, to tell the truth,
the only reason I bothered looking for something else was that my
Subie's the ONLY car I've ever owned that's persnickety about its oil
filters!

There ARE tests to determine how well the filter actually does its job,
but even they can result in skewed results if one says it's X% efficient
and the next one's only 0.95X%--are they testing the same thing? Look up
"beta ratio" for some info on how some of these tests are done. My tiny
bit of research indicates the industry's been pretty much on its own for
setting standards and advertising test results, though some people have
been working to come up w/ some universal standards so we're always
comparing apples to apples, not sometimes oranges, bananas and grapes.

But the pix ARE nice...


Not only nice, they provide valuable information.

From an engineering point of view the Fram filters may be
adequate for their application but from the consumer/market
economics point of view the consumer ought to know whether
he wants to pay USD 5.00 for quality A or essentially the
same amount of money for quality B. They seem to speak
a thousand words to me.

M.J.
 

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