is it really needed to change the oil every 5k miles?

[hedron]

I mean, since you have to dump a quart in every 500 to 1000 miles, what's the point of changing it? I mean, you'd only need to change it because of the filter. No? So, if you get a filter that's rated 20,000 miles you wouldn't need to change the oil for quite some time, just make sure you top it off every 1000 miles.

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[Kostamojen]

I assume its the 2011 Impreza in your description? Subaru recommends 3750 miles or 3 3/4 months under "severe driving", which is basically anything other than driving on a flat freeway at under 3000rpms for long stretches. Any hills, lots of stop+go, corners, etc. goes under "severe". If you use synthetic and drive under 10k miles a year, go for just once every 6 months.

You shouldn't need to add that much oil over time, you've got bad rings or valve seals and need a rebuild. Run a thicker oil like 5w40 to maybe help mitigate it in the mean time. Changing the filter gets the debris out that your motor is probably generating right now, if you leave it it just keeps building up and will get into the bearings and other important bits.

[Elbert Bass]

Go ahead and try that - come back and let us know how that works out for you.
20,000 mile oil filter, some people's kids....

Just to not be a total prick:
There are the acids and other chemicals that build up from the reaction with condensation in the crankcase.
The solids build up as the oil breaks down.
The additives in the oil break down (detergent, friction modifiers, etc...).
The oill filter medium clogs causing the bypass to open - no more oil filtration - all those solids getting in the oil passages and bearings.
I could go on but you would have ruined your engine by the time I finish.

[arse_sidewards]

Change your filter every 5-10k. Don't worry about the oil in the sump as it's never going to be more than a few thousand miles old with the amount you're adding.

[hedron]

Originally Posted by Kostamojen

You shouldn't need to add that much oil over time, you've got bad rings or valve seals and need a rebuild.

That's what I thought, but everyone I've talked to with this car has the same problem.

[Kostamojen]

Originally Posted by hedron

That's what I thought, but everyone I've talked to with this car has the same problem.

That specific car or Subarus in general?

The "Subarus burn oil" thing is a myth. I'm a former service advisor and parts guy, some of the newer cars (fb20/25 engines, in their early years) had actual bad oil burning issues that were difficult to deal with.

But the EJ engines only burned oil because of poor maintenance from owners along with lots of miles. I've had lots of customer car 200,000+ mile EJ motor cars around that don't burn a drop of oil, and none of my dozen or so ever have either.

[hedron]

Yea, the same generation Impreza.

[arse_sidewards]

1qt per thousand is fine, heck many OEMs won't consider that high oil consumption for a brand new engine.

Originally Posted by Kostamojen

That specific car or Subarus in general?

The "Subarus burn oil" thing is a myth. I'm a former service advisor and parts guy, some of the newer cars (fb20/25 engines, in their early years) had actual bad oil burning issues that were difficult to deal with.

But the EJ engines only burned oil because of poor maintenance from owners along with lots of miles. I've had lots of customer car 200,000+ mile EJ motor cars around that don't burn a drop of oil, and none of my dozen or so ever have either.

The boxor is fundamentally going to burn more oil than an equivalent displacement normal engine because there's less dead space vs swept space in the crankcase resulting in more windage to get sucked up via the PCV.


Combine that with with their propensity to blow the coolant out (especially during the head gasket era) and then get chronically run that way until they can be fixed resulting in lightly scored upper cylinders which results in higher consumption.


And then there's the valve cover leaks that nobody wants to deal with because they're kind of a PITA


You should know all this.

[crazyhunter2.5]

If you're burning oil then I guess, yes you wouldn't need to change it that frequently lol....but you may want to still frequently "change it" just to ensure you're looking at the dipstick and catch it incase it burns a little more than usual and you haven't looked at it for a while.