2009 Subaru STI Oil Recommendation

[after5hock]

Hey guys,

I read a sticky on here that says you may be able to give me some suggestions for what type of oil to run in my 2009 STI? I had just purchased it with 90,000 kms on it.

I will be running the OEM filters, and the manual calls for 5W-30.

I had looked on STI sites and the posts shows that everyone runs different oil, amsoil, RP, Mobile One. you name it.

I live in Vancouver, BC, the temperature here ranges from -10 Celsius in the coldest of winters to 30 Celsius on a hot summer day.

I drive from home to work and back every day, make trips to errands in around 40 KM legs, with lots of rest in between usually. I would say I drive an average of 50KM a day.

About half of that is in traffic condition, but not really stop and go condition, more like limited to 60km/h driving and with frequent stops for lights.

I like to drive the car kinda hard, but I RARELY go above 4000 RPM. I have my shift lights set to 4000, and I will usually shift before it goes off. Definitely no track stuff!

I am wondering what weight of oil to run? I read most of the Oil University stuff, but still don't know what oil I should be running to avoid excessive engine wear during cold starts.

I try to let the car idle when first starting for about 2 minutes or more, then will run very lightly (under 2000 RPM) until the engine (coolant im pretty sure) temp goes to normal operating condition.

I do not have a target for gas consumption, and I would probably change my oil and filter every 5000KM anyways even though people tell me that synthetic can run for longer.

people have told me the STIs like to drink oil, but mine seems to be doing fine on 5W-30 Liqui Moly synthetic oil. (from a mechanic when he changed my oil last, about 2000KMs ago)

I do not know this brand of liqui moly, and I would like to look into alternatives anyways (cheaper is good always!)

I am looking for a brand of oil and a weight to go with, i read that I should be aiming for a lower weight oil, then people say the low weight will shear easily and become even lower weight oil. (but isn't this a good thing? because you want less viscosity at lower temperatures anyways according to the oil university source on this site)

people on other sti forums say that I have to find a oil that works for my engine, because everyone seems to find ones that work well with their car. So I guess I am more concerned with what weight to aim to get for my running conditions with the car. any suggestions on the brand would be nice too!

anyways, sorry for the long post, I just want to find a good oil! Cheap is always an up if it doesn't cost me an engine eventually!

Cheers,
Peter

P.S. let me know if you would like more information to help with making an oil decision!

 

[Bandito440]

There are a million turbo Subaru oil threads, but I'll give you the recommendations that you'll see mostly. Most run heavier oils in these turbo motors.

Mobil 1 0w-40
Mobil 1 TDT 5w-40
Delvac 1 5w-40
Castrol 0w-30 or 0w-40
Rotella T6 0w-40 or 5w-40

Are any of them easy for you to get?

Run it for 5,000 miles with an OEM or Wix filter. Get a UOA if you want to go longer.

 

[after5hock]

Thanks for the recommendations!

What is the reason for running heavier oils in the subaru turbos?

and what is the difference between the 0w-40 and the 5w-40?

 

[901Memphis]

Depending or which specific oils we are talking about, generally a 0w40 will flow better at negative temperatures than a 5w40.

It's important to know where each oil is in the viscosity range and it's viscosity index.

Above freezing there's not much difference between most 0w40 or 5w40.

An important spec to look at is HTHSV or high temperature High shear viscosity. This tells you truly how thick the oil is in service. Some 0w30 oils have a higher HTHSV than other 5w30s, specifically ones formulated for European vehicles.

Looking at ACEA ratings.

http://www.oilspecifications.org/acea.php

 

[05LGTLtd]

Turbo boxers have a tendency to shear many 5w-30's to a 20grade very quickly. That's why an oil with hths rating of 3.5 or more is often recommended. The oils listed above are good choices. Synpower 5w-40 or Pennzoil PU 5w-40 are two more choices.

http://www.epc.shell.com/Docs/GPCDOC_X_cbe_24855_key_140007500286_20130123090_5.pdf

Since your in Canada, you may have access to rotella 0w-30 as well.

For your usage, I'd start with a PCMO like one of the castrol choices, the M1 0w-40, or Synpower 5w-40. Keep your oci at 4-5k miles and you should be fine. UOA is never really a bad idea with a new to you car.

LiquiMoly oils have some nice offerings, but due to cost and and availability, they don't get much use here in the US market. Motul has a small but proven following and uoa's generally look nice in these cars. Again price and availability.

 

[Ramblejam]

Originally Posted By: after5hock
the manual calls for 5W-30.

 

[wemay]

If going with a Xw40, Chevron's Delo 5w40 is also sold at WMart for less than M1 TDT. It's an API SM though, not SN.

 

[thunderfog]

Originally Posted By: 05LGTLtd
Turbo boxers have a tendency to shear many 5w-30's to a 20grade very quickly.


This. Lots of spun bearings with these engines.

On NASIOC, everyone seems to love the Rotella T6.

I'd go for a UOA also. Make sure you're not getting lots of wear metals already.

 

[Bandito440]

Originally Posted By: after5hock
What is the reason for running heavier oils in the subaru turbos?

As mentioned, these motors shear oil quickly. 40-weight oil and avoiding extended oil change intervals helps combat that.

Originally Posted By: after5hock
and what is the difference between the 0w-40 and the 5w-40?

Each oil has different properties, but in general the 0w-40 will have better cold start performance, but may also shear faster.

Are any of those oils I mentioned easier or cheaper for you to acquire? Amsoil Euro Full SAPS 5w-40 is another choice if you're an Amsoil guy. The majority of people that I know went with Rotella T6 5w-40.

 

[after5hock]

Thanks guys,
I am still hesitant to go with the heavier oil than 5W30
The manual does say it can run 5W40, but it says it prefers 5W30.

If I found an oil with higher HTHS than 3.5, would it be okay to use 5W30? I want to keep the wear on the engine to a minimum, and to do that, wouldn't I want a lower weight, to achieve lower friction and viscosity between components?

 

[Bandito440]

You won't see any wear difference between an HTHS of 3.5 and 4.0; be more concerned about shear, a hot turbo, and your bearings.

If you must use 5w-30, Amsoil HDD or Redline would be my choices.

Another note: check the NASIOC forum and you'll find another thousand oil threads suggesting 5w-40. It's generally accepted among the turbo Subaru crowd that these oils with an HTHS of 4.0+ are best for the application.

 

[thunderfog]

Originally Posted By: Bandito440
You won't see any wear difference between an HTHS of 3.5 and 4.0; be more concerned about shear, a hot turbo, and your bearings.

If you must use 5w-30, Amsoil HDD or Redline would be my choices.

Another note: check the NASIOC forum and you'll find another thousand oil threads suggesting 5w-40. It's generally accepted among the turbo Subaru crowd that these oils with an HTHS of 4.0+ are best for the application.


Follow Bandito's post. I'm telling you, there are scores of people over at NASIOC that have had problems with 5w-30 in their turbo Subies. Shear, shear, shear! Again, they love Rotella T6, and do not try to do extended OCIs.

 

[147_Grain]

Originally Posted By: thunderfog
They ... do not try to do extended OCIs.

 

[MCompact]

I am wondering what design characteristic(s) of the Subaru engine cause the oil to shear down. I am not doubting anyone here, but ask because I run M1 5W-30 in the DI turbo motor of my MS3 and the oil stays in grade for over 7,500 miles.

 

[thunderfog]

Originally Posted By: MCompact
I am wondering what design characteristic(s) of the Subaru engine cause the oil to shear down. I am not doubting anyone here, but ask because I run M1 5W-30 in the DI turbo motor of my MS3 and the oil stays in grade for over 7,500 miles.


I wonder if Bluesubie will chime in. He's pretty knowledgeable about this...much more than I am.

 

[MCompact]

M1 5W-30 gets slammed quite a bit on the Mazdaspeed boards as well, but in that case I don't think there is a factual basis for the bad rap...

 

[05LGTLtd]

SM PU 5w-30 showed a fairly good result in several Rex UOA 's if you really want to stay 5w-30, might check out how SN has been trending.

 

[Garak]

Originally Posted By: after5hock
I am still hesitant to go with the heavier oil than 5W30 The manual does say it can run 5W40, but it says it prefers 5W30.

If I found an oil with higher HTHS than 3.5, would it be okay to use 5W30?

If you do opt for a 40 grade, watch your pricing. An Imperial Oil or Shell distributor will give you your best pricing in Canada for Rotella 5w-40 or Delvac 1 ESP 5w-40. If you want a 5w-30 with an HTHS of 3.5 or higher, Imperial Oil will sell you Delvac 1 LE 5w-30 for under $7 a litre. There currently is no competing product, to my knowledge, readily available in western Canada.

 

[gpshumway]

Originally Posted By: MCompact
I am wondering what design characteristic(s) of the Subaru engine cause the oil to shear down. I am not doubting anyone here, but ask because I run M1 5W-30 in the DI turbo motor of my MS3 and the oil stays in grade for over 7,500 miles.


Check the oil at 2,000 miles in your MS3, it might be shearing down and thickening back up.

There's nothing about the Subaru boxer that makes it especially hard on oil relative to other high output turbo engines, but in many engines a thick 20wt is not much concern. Subaru EJ engines however, have fairly loose tolerances (and clearances) for the rods & mains. The factory tune is also a bit suspect on 2007+ cars, with a long delay at full throttle or near full throttle before power enrichment mode kicks in. The engine has to deal with a bit of knock especially on the 91 octane E10 fuel common in much of the country. The net effect is lots of EJ turbos fail by spinning the #4 rod bearing. The failures aren't that common overall, but of those that fail a spun bearing is very common. Broken ringlands (fron knock) are also fairly common. Those of us in the Subaru community who've studied the issue recommend a thicker oil as a basic safety margin against spun bearings.

All of this is true for EJ turbo engines from 2002, and especially 2007+, but not necessarily the new FB and FA series engines. It also doesn't apply to the non-turbo engines as they're a lot easier on oil and don't have the tuning issues.

To the OP:
If you read your owner's manual carefully it will recommend up to 10w50 for heavy use and high temperatures. The use of a light 40wt like M1 0w40, RT6 or TDT is a pretty small step up from 5w30. If you still are nervous about stepping up a grade, use a heavy duty 30wt with HTHS viscosity over 3.5 cSt. A common choice is Castrol Syntec European Formula 0w30. I personally am using Mobil 1 ESP Formula 5w30 which has been working well, it's expensive and a bit of an odd choice in many minds. I'll elaborate if you're interested. Redline 5w30 is the other good 5w30 choice, I've used it extensively. Expensive and in the bearings nearly identical to a 5w40 synthetic.

 

[after5hock]

Thanks guys,

So I think I am okay with going with the Rotella T6 5W40, I will probably be buying it in Washington when I drive down.

it sounds like a higher weight is the better choice. I just hope the start ups aren't too much wear on the engine! any start up tips to keep the wear to a minimum?

Thanks again guys, lots of useful info!