Need some advice for my 2008 Subaru Impreza STI...

[Merlot]

Hi, I just bought a new 2008 Subaru Impreza STI and I'm deciding what route to go with my oil. I previously owned (well, still own and trying to sell) a 2003 Subaru Impreza WRX.

With the WRX, I started out using Castrol GTX 5w-30 then at 7500 miles I switched to Mobil 1 5w-30 using that manufacture intervals of 7500 miles for normal driving. I switched to Rotella T synthetic 5w-40 after I rolled 100k miles. However, the check engine light has intermittently light up. I ran the code and it's one of my catalytic converters that's dieing.

Anyway, Subaru now says turbo engines need to change every 3,750 regardless, so I suppose I'll go that route. They also suggest to change both the oil and filter before and after a track day or autocross. I think that's overkill...

I was originally thinking of going with Rotella T synthetic 5w-40 after my first oil change. But here I read someone claiming it's too thick for Subaru's, and I'm a bit worried about an early death of my catalytic converters (I don't like to pollute), such as may be happening with my '03 WRX. So I'm thinking to remain within Subaru's guidelines of a preferred SM 5w-30 Energy Conserving oil, that I'd go with Pennzoil Platinum 5w-30. Is this a good choice? How about for autocross and an occasional track day? Do I really need to replace the oil and filter before and after such events?

Thanks!
Mike

 

[HTSS_TR]

PP or Valvoline Synpower 5W30 are good group III synthetic oils for your new car, your local Walmart may have Synpower at $4.01/qt, it is cheaper than $23/5qt jug.

5 qts German Castrol 0W30 on sale at Autozone for $29.99 with K&N oil filter included, is another good oil.

 

[rg200amp]

Id use Redline 5w30. Group IV Base oil. Top of the line for HIGH heat HIGH pressure turbos.

If you want to save cash, any name brand Synthetic oil will work great.
you can use a 0w30,5w30,0w40,or 5w40.

I would stick to a 0w/5w 30.

 

[iunderpressure]

Red Line uses group V base oil.

 

[scoobie]

You must replace ur oil before and after the meet. Otherwise a 4000 mile interval is necessary, or ur very nice engine will die.
a google search will reveal a sorry tale of dead engines.
the difference between a 40w and 30w UNDER RACE CONDITIONS, is VERY VERY LITTLE. I would encourage u to use redline for track day, an engine rebuild is quite expensive.

 

[webfors]

I want a wrx, or even better an STI, so I can finally worry about oil for a reason!!

My boring 2.5l NA forester doesn't need half the oil thought that I give it.

PP 5w30 or 10w30 is a great choice for those short intervals. Good oil, good price and should hold up well in that high pressure turbo sti. I'm soo jealous!

I've been drooling over other peoples cars a lot lately... Forgive me father, for I have sinned.. "thou shalt not covet another mans' ride"

 

[rg200amp]

Originally Posted By: iunderpressure
Red Line uses group V base oil.



Yes, Thats what I meant to say.

I was thinking of Royal Purple while I was typing!!

 

[Solo2driver]

I have 3 or 4 UOA's from a friend's '08 STi before it blew up (warranty, #4 piston defect and bad injector). 30-wt not sufficient in this application, just for the record.

Let me upload them somewhere and post them for you.

 

[rg200amp]

Originally Posted By: Solo2driver
I have 3 or 4 UOA's from a friend's '08 STi before it blew up (warranty, #4 piston defect and bad injector). 30-wt not sufficient in this application, just for the record.

Let me upload them somewhere and post them for you.



It may show alot of wear due to it being a new motor. alot of wear metals shown in the uoa's of a new motor is not alarming.


Post them up, so the gurus can give there views. I am intrested to see.

 

[Solo2driver]

Found the two UOA's, but I don't have any programs that can erase his personal information....I can email it to someone if you volunteer to "fix it" and post the pdf as an image. PM me.

Looking at them again, the problem was that the dealer dino 5w-30 and his next run of 10w-30 both sheared down to a 20-wt within 1K miles, either from abuse or fuel issues...with 7K miles total on engine. High in Al, Copper, and Silicon, SUS Viscosity @ 210°F below 55 and below 9cSt for a 30-wt. This is repeated in other people's reports from the '08 STi. With the new engine, my friend now is using Shell Rotella Synth 5w-40 with great results, as far as I know.

-JW

 

[rg200amp]

Originally Posted By: Solo2driver
Found the two UOA's, but I don't have any programs that can erase his personal information....I can email it to someone if you volunteer to "fix it" and post the pdf as an image. PM me.

Looking at them again, the problem was that the dealer dino 5w-30 and his next run of 10w-30 both sheared down to a 20-wt within 1K miles, either from abuse or fuel issues...with 7K miles total on engine. High in Al, Copper, and Silicon, SUS Viscosity @ 210°F below 55 and below 9cSt for a 30-wt. This is repeated in other people's reports from the '08 STi. With the new engine, my friend now is using Shell Rotella Synth 5w-40 with great results, as far as I know.

-JW


Yes, I can see the high heat and pressure of the turbo shearing dino oil out to a 20wt.

You have a good point.

I think a good synthetic 0w/5w 30 would/should work great.


Good point Solo2driver

 

[Merlot]

Originally Posted By: Solo2driver
Found the two UOA's, but I don't have any programs that can erase his personal information....I can email it to someone if you volunteer to "fix it" and post the pdf as an image. PM me.

Looking at them again, the problem was that the dealer dino 5w-30 and his next run of 10w-30 both sheared down to a 20-wt within 1K miles, either from abuse or fuel issues...with 7K miles total on engine. High in Al, Copper, and Silicon, SUS Viscosity @ 210°F below 55 and below 9cSt for a 30-wt. This is repeated in other people's reports from the '08 STi. With the new engine, my friend now is using Shell Rotella Synth 5w-40 with great results, as far as I know.

-JW


Hmmmm, so maybe I should run the Rotella T 5w-40 synthetic. I'm just worried about warranty issues because it's not Energy Conserving, and 5w-40 is a weight not listed in the Owner's Manual (although it does list a number of other alternative weights).

As an aside, I CAN NOT wait to run the STI through autox!

 

[Merlot]

Originally Posted By: webfors
I want a wrx, or even better an STI, so I can finally worry about oil for a reason!!

My boring 2.5l NA forester doesn't need half the oil thought that I give it.

PP 5w30 or 10w30 is a great choice for those short intervals. Good oil, good price and should hold up well in that high pressure turbo sti. I'm soo jealous!

I've been drooling over other peoples cars a lot lately... Forgive me father, for I have sinned.. "thou shalt not covet another mans' ride"

I had no intentions of picking up the STI, even though it was my "affordable" dream car; I was going to run the WRX until the wheels fell off. But then Subaru offered the 0% for 63 months and $7k of MSRP so I just HAD to get it!

 

[Audi Junkie]

Mobil 1 Hi-Miles 10w-30 in summer, any 30 weight synth in winter.

 

[joflewbyu2]

0% financing for up to 63 months and up to $5,000 dealer cash as these are not selling. Almost makes it tempting if I liked the 08 like I did my 05. Anyway, Subies have very robust engines. The boxer 4 has a stout super short crank. Castro 5w-30 is a great beak in oil for the 1st oil change after the factory recommended 1k change then change to a high quality synthetic. I fancy the Mobil 1 because of their plus years of experience and it is widely availability everywhere. I would start with 5w-30 till she is about 50k or burns oil in between changes then go to 10-30. I use Mobil 1 extended 5w-30 every 7,500 miles with a mobil 1 extended performance oil filter.

 

[Solo2driver]

Not that we need more fuel for the fire, but on the Subaru message boards it is fairly well-known that M1 5w-30 has proven inadequate for the turbo engines, and an unusual amount of spun bearings and poor UOA's (bearing wear) have surfaced when using that specific oil. It has gotten so that most generally shy away from any M1 products in their Subarus, but I do think that the TDT 5w-40 or 0w-40 would be fine, seeing that those particular product versions are very stout, if you must use that brand.

 

[joflewbyu2]

Originally Posted By: Solo2driver
Not that we need more fuel for the fire, but on the Subaru message boards it is fairly well-known that M1 5w-30 has proven inadequate for the turbo engines, and an unusual amount of spun bearings and poor UOA's (bearing wear) have surfaced when using that specific oil. It has gotten so that most generally shy away from any M1 products in their Subarus, but I do think that the TDT 5w-40 or 0w-40 would be fine, seeing that those particular product versions are very stout, if you must use that brand.
is that for regular mobil 1 or extended mobil 1 with 50% more additives?

 

[Solo2driver]

Originally Posted By: joflewbyu2
[/quote]is that for regular mobil 1 or extended mobil 1 with 50% more additives?


Doesn't seem to make a difference in this particular application.

 

[VK56VD]

Look into Valvoline MaxLife Full Synthetic 5w-30. This oil is very robust and on a thicker side of 30wt.

You can also go to a less expensive and more commonly available route of MaxLife Semi-Synthetic and change it every 3k miles to keep the engine clean and turbo healthy.

I'm not sure what is stated in your owners manual but when I/my family had a '92 Legacy with the EJ22 engine, it was on a diet of 10w-40 all it's life w/o issues. I believe this was the recommended oil for all temp. ranges.

 

[VK56VD]

Below is the image of my '92 Subaru Legacy Owner's Manual Oil Recommendation pages. It clearly shows to use a thicker oil when the engine see's more heat and stress, such as in the case of AutoX that you plan to do. 5W-30 is not suitable for cooling and lubrication under these circumstances. In fact, they recommend 10w-40 & 10w-30 for relatively all temperature ranges under normal driving.

This manual is from '92 but unless the engine design changed significantly in this flat 4 configuration, I would assume the same would apply for your STI. Manufactures are pushing the 5w-30 energy conserving oil for these engine for optimum fuel economy but probably at the cost of engine durability and reliability after the warranty period expires, such as in the case of spun bearings of M1 5w-30 users. The M1 probably did shear down to a 20wt oil and did not provide enough cooling and lubrication for proper operation of those engine. If a more robust and thicker oil was used, Ie: 5w-40, 10w-40 the spun bearings never would have happened. I hope these 2 pages help as they clearly show a need for thicker oil as stress and temperature increases. I hope this info still applies to the '08 STI engine. If you look at the second page, SAE 30, SAE 40, 10w-50, 20w-40 and 20w-50 are recommended as suitable to use in extremely heavy duty and high temperature applications in this engine. The recommendations above are the same for the EJ22 (2.2 n/a) flat 4 and the EJ22T (2.2 Turbo) flat 4 engines.