I have a question about the likelihood of my warranty being voided.

1481 Views 26 Replies 15 Participants Last post by AstroKats, 7 d ago

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Discussion Starter · 21 d ago

Hey guys,
2023 crosstrek 2.0l 6mt.
I've had it for a month now. It currently has 4,700 miles on it. I purchased the car with 0 miles.

When I do the first oil change, (After I run out of my 4 free dealer changes). I would like to switch to a 0w30 or 5w30 since I live in central Mississippi. It's hot out here.
It would also make me a little more comfortable with fuel dilution.

Will switching to a quality 0w30 or 5w30 void my warranty? (I use mobil1 in everything else.) I didn't really see any specifics in my manual regarding oil weight.

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[email protected]

· #21 · 19 d ago

unless your family rat you out how the dealer gonna know? worst case, put in 0W20 before warranty repairs. But I highly doubt they care.

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ProfMonkey

· #22 · 17 d ago

Oil ratings involve a bunch of tests and cover a range of values for various parameters.

There is a lot of overlap between grades. If the dealership tested your used oil it would be nearly impossible for them to definitively say which grade it was when new as numerous factors can change the viscosity as the oil is used/ages. They'll be looking for evidence that your oil changes weren't frequent enough - too much fuel dilution and too thin viscosity or too thick from oxidation, TBN depleted, sludge, etc.

The only reason I see to go outside of the recommended grade is if you're regularly seeing high oil temperatures due to extreme climate or use (towing). ie. A resource conserving 5W-30 (non-euro spec) will have the same viscosity at 230F as a 0W-20 at normal operating temperature of 212F. Subaru manuals do say that a higher grade might be necessary for proper protection in high heat, but don't provide any guidance on what to use.

Put in what's appropriate for your temperatures, change the oil regularly, keep records/receipts of the changes, and enjoy driving.

FYI: Idemitsu's (Subaru) new 0W-16 that's called for in the 2024's has a 100C viscosity of 6.866 cSt.

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jack ffr1846

· #23 · 10 d ago

MA Subie said:
Yes.

Well, there are 2 proposals there. Tolerances are looser in order to reduce friction in order to increase MPG. Oil viscosity is reduced in order to increase MPG alone. Maybe you're not old enough to have been into roadrace car building years ago, where looser tolerances were used to build race engines so resistance was reduced to get more power out of the engine. But oil used back then was pretty consistently raised to 50 weight. Today, it's become opposite world in order to meet the MPG requirements.

In my 13 Crosstrek, we had the short block replaced by Subaru under warranty at 98k miles for oil consumption. Hey, free Legacy loaner car for 2 weeks and a new short block and the valve springs replaced while we're at it. I just did an oil change yesterday at 190k miles (about 90k on the short block) and I've found that if we use 0w 20, the oil light comes on before 3000 miles. What did I do the change with yesterday? 10w 40. This will hopefully get the car 5000 miles until the next oil change without an oil light. If not, yes, I'll up it even more.

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Fate

· #24 · 9 d ago (Edited)

jack ffr1846 said:
Well, there are 2 proposals there. Tolerances are looser in order to reduce friction in order to increase MPG. Oil viscosity is reduced in order to increase MPG alone. Maybe you're not old enough to have been into roadrace car building years ago, where looser tolerances were used to build race engines so resistance was reduced to get more power out of the engine. But oil used back then was pretty consistently raised to 50 weight. Today, it's become opposite world in order to meet the MPG requirements.

In my 13 Crosstrek, we had the short block replaced by Subaru under warranty at 98k miles for oil consumption. Hey, free Legacy loaner car for 2 weeks and a new short block and the valve springs replaced while we're at it. I just did an oil change yesterday at 190k miles (about 90k on the short block) and I've found that if we use 0w 20, the oil light comes on before 3000 miles. What did I do the change with yesterday? 10w 40. This will hopefully get the car 5000 miles until the next oil change without an oil light. If not, yes, I'll up it even more.

You do realize that that oil light comes on when the oil is around a quart low, right?

I'm old enough (really) and raced and built enough to know a few things, too.

One is, whoever is responsible for a vehicle checks the oil at least every other fill of the tank. Further, should that person find the oil low, to about any degree whatsoever, they top the oil off to the Full mark. No one waits until the oil is a quart low before adding oil for several reasons: Consumer vehicles only hold just enough oil to both supply the engine with oil under all conditions, it is also responsible for cooling the engine... especially the hotspots near the combustion chambers, which is crucial to the machinery's long term life (rings, valve system, for example). The water jackets only do so much.

So running a few thousand miles with a significant percentage of the engine oil missing isn't, IMHO, responsible maintenance. That requires the remaining oil to do it all... which significantly accelerates its aging and reduces its ability to oil and cool.

Subaru's low oil warning light was implemented in the first place to reduce their warranty costs... repairing and replacing engines for the dummies who never checked their oil. It was never intended to be used as a reminder to add oil. It's a warning.

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MA Subie

· #25 · 9 d ago

Fate said:
You do realize that that oil light comes on when the oil is around a quart low, right?

I'm old enough (really) and raced and built enough to know a few things, too.

One is, whomever is responsible for a vehicle checks the oil at least every other fill of the tank. Further, should that person find the oil low, to about any degree whatsoever, they top the oil off to the Full mark. No one waits until the oil is a quart low before adding oil for several reasons: Consumer vehicles only hold just enough oil to both supply the engine with oil under all conditions, it is also responsible for cooling the engine... especially the hotspots near the combustion chambers, which is crucial to the machinery's long term life (rings, valve system, for example). The water jackets only do so much.

So running a few thousand miles with a significant percentage of the engine oil missing isn't, IMHO, responsible maintenance. That requires the remaining oil to do it all... which significantly accelerates its aging and reduces its ability to oil and cool.

Subaru's low oil warning light was implemented in the first place to reduce their warranty costs... repairing and replacing engines for the dummies who never checked their oil. It was never intended to be used as a reminder to add oil. It's a warning.

And I'm old enough to remember when some car engines inherently burned off the first quart of oil and stayed there. My dad had a 1971 AMC Gremlin which did this throughout its life until it was totalled at 130K miles. The engine was still good.

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r135130s

· #26 · 7 d ago

I'm not sold on 0W16 since it is largely a function of fuel mileage and not protection. I asked someone I trust at my dealership about running a heavier grade of oil. They said Subaru never asked them about oil grade when a customer had a warranty claim. But they always asked for documentation for oil change intervals.

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AstroKats

· #27 · 7 d ago

r135130s said:
I'm not sold on 0W16 since it is largely a function of fuel mileage and not protection. I asked someone I trust at my dealership about running a heavier grade of oil. They said Subaru never asked them about oil grade when a customer had a warranty claim. But they always asked for documentation for oil change intervals.

That's what I would expect, especially since the manual says you can use a heavier weight oil.

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