Mobile1 15w-50?

[wrx666]

Hi kids,

Say, i've been snooping around the forum and I've read that using 15W-50 will void our warranty. Is this true? Any thoughts on why or is it just that it's been printed that way. And does it say that using this oil will VOID (note caps) the warranty? Thoughts? Thanks for your time.

[GV27]

Well, void is too strong a word. Nothing can completely void your warranty, but lots of things can be the basis for warranty service being denied on certain parts. If you run 15-50 and you lose a bearing in the motor it is conceivable that SUbaru might decline to service it due to the thicker oil being used.

The problem w/ 15-50 is w/ flow - especially cold flow. Cars designed to run on thinner oils often have smaller passages for the thinner oil to flow through. Trying to put a thicker oil through those smaller passages could result in oil starvation of certain parts of the engine resulting in failure.

C

[SD_GR]

15W-50 is not listed in the manual.

You can actually run a 20W-50 and be perfectly *fine* with the warranty in the US. A dino 20W-50 will run like molasses compared to Mobil 1 15W-50. If you can find M1 20W-50 (not in the US!) it won't be API SL rated, so it's out too despite being a "blessed" weight.

You can also run a 10W-50 (you might have a look around in Australia to find one...) as long as it's API SL (it won't be...). But since 15W-50 is not *specifically* on the ordained list in the manual, it's off.

The M1 15W-50 itself is one of the best oils available *anywhere* in the world; it's an ACEA A3-02 oil with better low temp pouring than many conventional 10W-30s and ought to flow well most places south of Wisconsin even in winter.

It's really an issue of semantics, but it's best to be cautious. I'd not mind using M1 15W-50 or M1 0W-40 at all, and have no doubt they're both excellent. But the manual says otherwise so I run 10W-30 M1 and will do so for the next 45K miles. After that I'm free to run anything I please.

SD

[bdoug]

Yep, SOA is a crazy beast.

10W-50 and 20W-50 are OK, but 15W-50 is strangely omitted. Heck, even a straight 30 or 40 weight oil is allowed.

I also find it interesting that, in other countries, Subaru actually recommends a 15W-50 synthetic oil for the WRX.

Anyway, I run M1 0W-40 (unless you work for SOA, then it's 5W-30 dyno)

[wrx666]

Hey guys, thank you very much for your time and informative posts.

Upon re-reading the manual, i guess it's quite obvious that they've left the 15w50 out of the picture. Living in the steamy south, i was hoping to use something in the 50W category, but i think i'll stay w/ the 10w-30.

On another note, Should i be doing more than just tire rotation and an oil and filter change at 7.5K? My manual says that is all (or that's how i interpret it ), but i would hate to overlook something.

BTW, this is one of the best bulletin boards out there.

[SD_GR]

Since the wheels are off, clean them all, including the back of each rim, and check for any damage. Check along the tread on each wheel also. Remove any stuck gravel etc., and look for nails and weird wear patterns. Adjust the pressures since you've rotated wheels (I think it's 220 kPa front, 200 kPa rear for size 205/55/16, other pressures apply for 17s; check the driver's door sill plate for correct #s). Check the spare.

Check the brake pads through the caliper inspection slots, check the lines visually for scuffing or leak problems, check all the hoses and rubber parts on the driveshafts for slits, check everywhere for oil stains and grease smears. Once you put the wheel back on, check for wheel bearing damage by wiggling laterally etc.. You might also want to have a look at the steering while you're poking around under the car.

Check all the fluids under the bonnet too - gear oil, steering and clutch fluid, battery electrolyte, motor oil, coolant, washer fluid etc.. Glance at the external belts and the battery terminals.

Wipe the undercarriage down so you have a reference point to go from for next time.

[Lightndattic]

I'm running M1 15W-50, but I live in Texas where it's routinely 90+degrees. My oil temp is regularly running 90-100 Celcius, so I figured a heavier oil wouldn't be a problem.

Once it starts getting cooler, I'm switching back to 10W-30.

[SD_GR]

I've gone through about 400 ml of M1 10W-30 in 3600 miles, and expect to use about 600 ml in my 5,000 oil change interval (put oil in at 15,000 miles, will change at 20,000).

What consumption are you seeing with the 15W-50 vs. the 10W-30? I realise the environment is different (winter vs. summer) but am curious to see if my motor's use is typical. I use 10W-30 year-round.

Thanks!

[WRXG0blin]

I just did an oil change to 10w-30 due to the extreme desert heat we have. Hawwwttt.

[stickman]

what about M1 5w-30 fully synthetic.

should i be worried?

[SD_GR]

Sorry but what are you asking? Should you worry about what?
SD

[stickman]

Originally posted by SD_GR
Sorry but what are you asking? Should you worry about what?
SD

that im using 5w-30 instead of 10w-30.

[GV27]

That's fine. Most people in colder climates run 5-30 in the winter.

Actually 15-50 is fine as well - I hadn't looked at my owner's manual in a couple of years and had forgotten Subaru's extremely abiguous recommendation when I posted my comments above. With the wording in there, anything will work and you'd have an excellent case if it ever came to it - but I'm quite sure it wouldn't with the wording they use. If 10-50 and 20-50 are on the recomended list, 15-50 will be fine since the lower number is between the two and the higher number is the same - there's just no way they could logically argue that 15-50 shouldn't be used. There's no "magic" to the numbers - you just want to make sure you have enough flow in both hot and cold situations. Cold usually being more important as, for example, with a 20w-50 the oil is actually "thicker" when cold than warm, even with a big spread in the viscosity grades.

Only in cases like a normal manual where they say something like "use 10-30 summer, 5-30 winter" could there be a potential warranty problem - they could easily say that 15-50 is too thick acd they warned you against it. In Subaru's case usinf either viscocity so you're OK.

Personally I wouldn't use 15-50 'cause I want good flow when cold. But that's just my thang. I've switched all over the place trying to figure out what I want to use. I have been using 5-30 M1 as that's what my wife's car takes as well, but may switch to the 0-40.

C

[SD_GR]

Originally posted by GV27
That's fine. Most people in colder climates run 5-30 in the winter.

Actually 15-50 is fine as well... With the wording in there, anything will work and you'd have an excellent case if it ever came to it - but I'm quite sure it wouldn't with the wording they use. If 10-50 and 20-50 are on the recomended list, 15-50 will be fine since the lower number is between the two and the higher number is the same - there's just no way they could logically argue that 15-50 shouldn't be used.
C

I fully agree logic is on your side, and am completely convinced your position is well thought out and founded on good reasoning and science. 15-50 will work just fine, no question.

My worry is that nobody has established a relationship between SOA and logic!

So I'm taking a more coservative (OK, anal retentive, I accept it) stance on this one. When I pass the warranty mileage I'll consider M1 0W-40 like you say, or 15W-50; although I think you're right I am unsure what SOA would think and don't want the 1 in million chance of a hassle.

[GV27]

I can sorta see your concern. But really it's gonna be awful hard for them to tell the difference between 15-50 and 20-50. And I've yet to hear of a warranty claim being denied by SOA over something as small as that. In fact the only claims SOA has denied have been pretty major - bigger turbo, etc.

As far as the dealership is concerned they're not gonna know or care the difference if there's somethin' oil colored in there. Yeah, if my tranny goes and they see my powder-blue Redline Shockproof in there they might have something to say - but when the manual says you can use straight 40-weight ( ) I just can't see them spending anytime to figure out if you had 10-50, 15-50 or 20-50 in there!