3,750 mile OCI too extreme??

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Originally Posted By: OVERKILL
Originally Posted By: lubricatosaurus
Otherwise, Subaru is saying the SN GF-5 based full synthetics are the ones that can go almost 4,000 miles, got to believe that.


Does Subaru spec a synthetic 5w-30? I don't believe so, I think it is just your typical 5w-30 PCMO.


For a 2015 WRX or WRX STI (turbo), Subaru says use a full synthetic of 5w-30 or 0w-30 or 5w-40 or 0w-40. I'm not sure about the other turbo Subies. That means any euro-spec 0w-40 or 5w-40 is warranty approved. Of course M1 0w-40 is a tougher oil than M1 0w-30, so my reasoning is that a 0w-40 can go longer, although Subaru doesn't bother making that distinction, they consider all oils equal. Consider 0w-40 will handle fuel dilution better as well and still have reserve viscosity left over. Any oil like M1 0w-40 that is approved for everything from Nissan GT-R's to Porsche GT3's to Audi A4's might survive in the Subie turbo models.
 
Originally Posted By: lubricatosaurus
I see IF its a 2015 Forester subie turbo, then Subaru just says use a full synthetic 5w-30 or 0w-30.


Looks like the OP has an '08 WRX:
Originally Posted By: OP
BUT my 08 WRX is leak free with 62k miles. The only mechanical issue I've had with it was with the intake manifold gaskets not sealing against the head. Got it replaced with a redesigned gasket and it's all good now.


Link to OP's post in another thread

From the 2008 Owner's manual, found here:
http://www.wrxinfo.com/owners_manuals/

It states:

Originally Posted By: Subaru

Oil grade: ILSAC GF-4, which can be identified with the ILSAC certification mark (Starburst mark) or API classification SM with the words “ENERGY CONSERVING”

ILSAC Certification Mark (Starburst Mark): In choosing an oil, you want the proper quality and viscosity, as well as one that will add to fuel economy. The following table lists the recommended viscosities and applicable temperatures. When adding oil, different brands may be used together as long as they are the same API classification and SAE viscosity as those recommended by SUBARU.

SAE viscosity No. and applicable temperature *: 5W-30 is preferred. Engine oil viscosity (thickness) affects fuel economy. Oils of lower viscosity provide better fuel economy. However, in hot weather, oil of higher viscosity is required to properly lubricate the engine.

Recommended grade and viscosity under severe driving conditions If the vehicle is used in desert areas, in areas with very high temperatures, or is used for heavy-duty applications, use of oil with the following grade and viscosities is recommended.
API classification SM (or SL): SAE viscosity No.: 30, 40, 10W-50, 20W-40, 20W-50


Then regarding synthetic oil:

Originally Posted By: Subaru

Synthetic oil: You can use synthetic engine oil that meets the same requirements given for conventional engine oil. When using synthetic oil, you must use oil of the same classification, viscosity and grade shown in this Owner’s Manual, and must follow the oil and filter changing intervals shown in the maintenance schedule


So it would appear as to the OP's vehicle, a synthetic oil is not spec'd, but if he uses it, he still has to change it at the same interval. I'd imagine this is due to the 4 quart sump, which is insanely small for a turbo engine IMHO.

I ran M1 0w-40 in our '05 Forester XT we had briefly (that was bought back and we got the Charger to replace it). It was quieter than the 10w-30 that was spec'd for it but I'd be hesitant to extend the drain intervals due to the small sump size and tendency for the engine to fuel dilute.
 
Originally Posted By: OVERKILL
So it would appear as to the OP's vehicle, a synthetic oil is not spec'd, but if he uses it, he still has to change it at the same interval. I'd imagine this is due to the 4 quart sump, which is insanely small for a turbo engine IMHO..


It wasn't until years later (last few years) Subaru went to full synth-only in their WRX. In 2008, they were saying you could use the worst oil you could find on the shelf basically, just an SM oil ! That tells us something. Those OCI's were short due to the weakest oil used. Therefore, you should easily go to a M1 0w-40 or Castrol 0w-40 and go twice as long since they are more oxidative stable.
 
It appears to me that Subaru cares more that fresh oil, meeting at least API SM is kept in the sump and changed often, over any high end synthetic. That would explain:

Quote:
Synthetic oil: You can use synthetic engine oil that meets the same requirements given for conventional engine oil. When using synthetic oil, you must use oil of the same classification, viscosity and grade shown in this Owner’s Manual, and must follow the oil and filter changing intervals shown in the maintenance schedule


...basically what Hyundai says too.
 
Originally Posted By: wemay
It appears to me that Subaru cares more that fresh oil meeting at least SM is changed often over a high end synthetic. That would explain:


Subaru learned something 3 years ago that we should learn now. Use a full syn in the hard-use WRX turbo models. Sure 8+ years ago Subaru was saying put in SM dino and change 'weekly' but later they said synth-only. I'd think the newer synth-only rule could apply to earlier WRXs for benefit.
 
Originally Posted By: Nick1994
If it's under warranty, go by the owners manual.

If it's not under warranty, go 5,000 miles and get a UOA and see if you can stretch it out further.


+1
 
Originally Posted By: camrydriver111
Originally Posted By: wemay
Agreed

http://www.waynesubaru.com/oil-change-guide.htm


If this information is accurate synthetic is 7.5k and not 3.75k.

I agree, and in most applications synthetic should be good for at least 7.5k if not more.


Ah, but that information is not correct for the OP's 2008 WRX. The original recommendation was for SM oil for 7500 miles. Due to problems with coking and the resulting plugging of screens in the turbo and VVT oil feed lines, a TSB was issued changing the OCI to 3700 miles and requiring synthetic oil. Now you know the rest of the story.

Ed
 
Originally Posted By: wemay
Boy, how often does Subaru change their recommendations?


Every time they figure out the engineers were right and the marketing department was wrong.

Ed
 
That reminds me of how Infiniti had (not sure if they still do) regular service intervals, severe service intervals, and platinum (or some such thing) intervals. The latter were much the same as the severe, with extra things to be checked, of course to make the dealer upsells much easier. Now, they should have engineer based intervals as separate from the marketing based ones.
wink.gif
 
Originally Posted By: Garak
That is true, but I'm also thinking how some makes prefer to treat everything that isn't engine oil (and possibly coolant) as lifetime fills.
wink.gif



+1
 
You could probably extend your intervals to 5-6k if you switched to Mobil 1 0W40 or if the clog prone banjo bolts have been removed.

Remember - No one from bitog will pay for your turbo replacement.
smile.gif
 
Originally Posted By: bluesubie
You could probably extend your intervals to 5-6k if you switched to Mobil 1 0W40 or if the clog prone banjo bolts have been removed.

Remember - No one from bitog will pay for your turbo replacement.
smile.gif



Good reminder, and absolutely true. My sig car calls for 3k miles on M1 0w-40. Do I extend it? Nope. Fuel dilution is the reason, but whenever you have a special situation oil is cheap. I bet a new turbo can get expensive...
 
Originally Posted By: SteveSRT8
Originally Posted By: bluesubie
You could probably extend your intervals to 5-6k if you switched to Mobil 1 0W40 or if the clog prone banjo bolts have been removed.

Remember - No one from bitog will pay for your turbo replacement.
smile.gif



Good reminder, and absolutely true. My sig car calls for 3k miles on M1 0w-40. Do I extend it? Nope. Fuel dilution is the reason, but whenever you have a special situation oil is cheap. I bet a new turbo can get expensive...

Around $2k when I had mine replaced by the dealer after failure due to clogged banjo bolt screens!

Quote:

Under normal driving conditions, the recommended oil and oil filter change interval for turbo vehicles is every 3,750 miles or four months, whichever comes first.
However, for vehicles driven in conditions beyond normal, such as racing conditions, the oil and oil filter may require more frequent changes.

http://drive2.subaru.com/Sum08/Sum08_Turbo.htm

Here's Amsoil's guidance for the OP's MY:

Quote:

Subaru has published Service Bulletin # 02-103-07 that identifies a factory design related problem with premature clogging of the oil mesh screen located inside the oiling system that supplies the turbo charger on all model turbo charged cars. A clogged screen will result in oil starvation and turbo charger failure.

Subaru has since published Service Bulletin #02-110-10R indicating that 2010 MY and prior turbocharged engines continue to require oil and filter change intervals of 3,750 miles (6,000 km) or 3 3/4 months, while all 2011 MY turbocharged engines have returned to the original requirement of 7,500 miles (12,000 km) or 7 1/2 months, and they are required to use synthetic oil.

Due to the issues outlined in this document, AMSOIL recommends following Subaru drain interval recommendations.
 
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