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Discussion Starter #1
I'm do for my first oil change. I've always changed over to fully synthedic, never had a turbo or subaru. Is the subaru performance oil a special blend to get the most out of your boxer engine? or should i just change over to full syn.?
 

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I was wondering the same thing, im due in about 800KM, i always used Mobil 1 in my other car. thx for bringing this question
 

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Discussion Starter #3
I just set up my apt. for tomorrow. I'll see what they say and let u know. I also asked them about retuning, theres no charge. That depends on your dealer tho.
 

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Im doing my oil change myself, my father is a mechanic so i have every snap-on tools and a hydrolic lift :D

but they told me i have to buy a OEM oil filter from them for warranty reason... Do you know if there is a different more performant oil filter for STI ? maybe you can ask them hehe
 

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Discussion Starter #5
Never thought about the sti filter option. I'm all about changing it myself, my first 3 oil changes r free tho. If its free its for me! I'll deff. see about the sti filter tho. thanks bro!!
 

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On my 04 I used Castrol Syntech and never had an issue with it. I felt that was a pretty good oil, but there are some better oils out there. Anyone have an opinion on the best synthetic oil?
 

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On my 04 I used Castrol Syntech and never had an issue with it. I felt that was a pretty good oil, but there are some better oils out there. Anyone have an opinion on the best synthetic oil?
haha if we were to discuss about which is the "best", the discussion will NEVER end hahahaha
 

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I tend to run regular oil in my cars for the first 5k. The way I figure it is they ship it with regular, they expect the majority of people will use regular, so its likely a good ide to let the engine break in on the stuff expectation they designed around. I've never had a problem switching over to synthetic afterwards. (Mobil 1).

Regarding oil in general, Motorcraft (a Ford subsidary) sells an "OEM" sythetic blend that is cheaper then the branded ones. I highly recommenced it. I put it in the wifes Jeep for a while with no issues, costs the same about regular oil and we saw a +2mpg from just doing that.
 

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Discussion Starter #10
From What the dealer told me the STI oil filter is the same as the WRX. As for oil they said changeing over to fully synth. would be a better choice. They use mobil 1. Hope it was a help. I might switch to a K&N oil filter and try the blitz that pehon mentioned.
 

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My cars is due for its first oil change this week. I'm going to use Royal Purple.
 

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When are you guys going in for your first oil change? With my other WRX I keep regular oil in until the first oil change and then swapped out for synthetic. I was told that the regular oil helps the gaskets seal properly during break in and that is why you use it in the beginning and then you change over to synthetic.
 

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I will do the first one at 1500 miles and the second one around 5000 miles. Both on Dino oil, then switch to Synthetic and change every 5k. I know some will say that is to long, but it is what I did with my last WRX and it went 100k without as a burp from the engine.
 

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I will do the first one at 1500 miles and the second one around 5000 miles. Both on Dino oil, then switch to Synthetic and change every 5k. I know some will say that is to long, but it is what I did with my last WRX and it went 100k without as a burp from the engine.
To long? I usually go 8-10k on full synthetic, and thats with auto-xing. :)
 

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I went to a local oil change place. brought my own oil and filter. Royal Purple FTW.
Since i kind of know one of the guys at the shop, i just gave him some money. Worked out well for both of us.
I didn't have to change my oil out in the freezing cold and he got $10 in his pocket.
 

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I hate to point to another board for answers, but nasioc.com has FULLY discussed oils and which ones are the best for our engines...although there are some varying opinions.
I've been a member on there and rs25.com for about 4 years. Although I just got my 08 impreza, so I'll contribute to this community a bit :)

Sooo....

I've also been considering this question as my first oil change is looming...

In a nutshell...not only do you need to consider the brand/type of oil, but the viscosities numbers as well.

Synthetic oils are really good and you can go longer between changes, but they tend to be alot thinner than conventional oils and *can* cause oil leaks in older engines (especially when the engines are pushed hard) Oils like Mobile 1 fully synthetic 5w30 are pretty thin. Many RS/WRX/STI drivers have reported that they have had undue engine wear using m1 5w30 (blown engine bearings, that sort of thing)...or a leak problem (not burnoff). Once these individuals switched to a thicker fully syn oil or switched to conventional again, the oil leak stopped and/or they didn't have any more engine issues.

That being said, I used m1 5w30 in my RS till about 95k miles and never had a problem....no leaks, no engine damage...and I did autocross for about 2 seasons. However, people have done alot less than blown their engine....your mileage may vary.

People have pointed to faulty engineering on subaru's part for these blown engines and not the oil...others to specific driving styles of owners and racing their vehicles.

The owners manual recommends (or at least it used to, not sure about the 08 manual) using a higher viscosity oil when pushing the engine harder than normal or living in an excessively warm climate.

An explanation of engine oil viscosities and what that numbers mean are below...I did NOT write this, but it is correct as far as I can tell and it is well written.

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A note on oil weights...
Example: 5w30
5w30
where the 5 is the base weight. The lower the weight, the more refined the oil, also thinner. The lower the number, the more usable it is in cold temps. I'll note the government is testing sub 0 weights right now in cars. Tighter tolerances means thinner oil and better fuel economy.
5w30
where the w is just a winter/cold weather designation for the oil
5w30
where the 30 is the equivalent "hot" viscosity. A 5w30 will be as thick as a straight 30 weight oil when hot, which will be relatively thin compared to cold for a straight 30 weight. This is the important number as this is the primarly operating viscosity.

So, what's good then? Well, ideally we'd like a flat, "optimum" viscosity throughout the operating temperature range, potentially from -20F to 200F. A straight 30 weight oil will be very thick cold and thin out very quickly as it heats up. There's a steep curve. A 10w30 provides a thinner base oil so cold viscosity isn't tremendously high but has additives that allow it to stay relatively thick as temps go up, enough so that the thinner 10 weight oil acts like a 30 weight oil when hot. Further steps are 5w30, 0w30, 5w40, 0w40, etc. As we get more progressive, we get to this flatter "optimum" where the viscosity really doesn't change at all through its entire temp range. A 0w40 oil provides nearly ruler flat viscosity from cold to hot resulting in very minimal thinning of the oil when hot. The best available that I'm aware is 0w40. It offers the very good cold weather usability of a 0 weight oil with the relative thickness of a 40 weight oil when hot. If you need a 50 weight hot viscosity, I think the lowest base is 10, but I've never really looked for those.

So what's right for you? Well, anything that fits your application. If you don't see temps much below 60F, a 0 weight or 5 weight base oil really isn't needed. It's simply extra cost to you for no real benifits. If you see -20F, a 0 weight base is very benificial. The same applies for the "hot" side. Normal operation only needs 30 weight equivalent hot, 0w30, 5w30, 10w30 will all be the same here. If you're hard on the vehicle, you might consider a higher "hot" viscosity, so 0w40, 5w40, 10w40, etc. You pic the weight ranges for your application.

So you live in southern California and you are light on your car. All you need is 5w30. Well, what if you run 0w30 or 5w40? Will anything bad happen? Nope. You're simply overprotecting yourself and probably spending more than you need. There's no downside to running a 0w40 in a car that's intended for 5w30. The world won't end. In fact, it's safer. The engine will be more usable cold and better protected hot. You just pay a premium as that super oil will most likely be synthetic and expensive. Isn't a 0 weight too thin? No. Hot viscosity is always thinner. Even a 0w40, it will be thicker cold. It will also pump easier and build pressure quicker.

One note on oil consumption. I've read it's normal when you switch types that there will be some consumption. I can't say why. Chemical make up, whatever... If you find the car loosing oil, then bump up the "hot" viscosity. Go from a 5w30 to a 5w40. That will limit burn up.

When I first went to Mobil 1 synthetic(0w30), I too noticed consumption. After around 2000 miles I needed to add another quart. I then switched to 0w40 and that stopped. Later I used up some extra 5w30 dino I had left over, ran through that and switched back to Mobil 0w30 again. I have not seen any consumption since. I probably could have stayed with 0w30 on the second change and not noticed any either, but I've been back on it for a little while now and no problems.

Dino vs synthetic? I don't know enough to comment much on this, but I know a few things. Dino is always derived from petroleum, and there's always some level of contaminants(sludge). Cheapy oils may have higher numbers, but most oils today are pretty good, far better than the oils of yesteryear. Group III oils, sometimes referred to as "hydro crack" oils are the very clean versions of dino, sometimes enough so that manufactures like to label them as synthetics and slap on a high price. This is similar to synthetic blends, which are majorly dino oil with a small amount of synthetic blended in for a premuim price. Reguardless of marketing, these Group III oils are very clean oils. Synthetics are man made and have zero contaminants(zero sludge), the only type that doesn't have any. These are labeled a Group IV. No dino oil can be labed as a Group IV oil. A Group V exists, but it's not a motor oil but more of a pure base that's used in laboratories to produce the Group IV oils.

A side note on additives...
Additive packages make the oil behave the way it does. It makes thin 5 weight base oil stay as thick as 40 weight oil when hot. Most oils use relatively simple additve packages, small chain polymers that get the job done. However, when we push the envelope, we create fancier, bigger polymer chains. We can stretch the capability of the oil so we can make a thinner 0 weight base stay as thick as a 40 weight when hot or a base 5 weight stay as thick as a 50 weight oil when hot. The downside with this is that these uber long(many magnitudes longer than the simply polymers) polymers are prone to getting sheared appart during normal engine operation. The PAO type synthetic Mobil 1 uses is like this. You get this great 0w40 oil that does everything you ever wanted, but the complex polymers break down quickly. The oil breaks down faster than a simpler type. During extended use, your 0w40 will turn into a 0w30 and then a 0w20 as the additive package breaks down. For a standard 3000 or 5000 mile change, it's not a big deal. However, some do push intervals, especially industry and the break down time has to be taken into consideration. For those that are heavy on their cars, they may also have to keep this in mind. A 5w30 with a simple additive package may last 7500 miles withouth breaking down too much, but a 0w30 with a complex one might degrade enough to no longer protect. You may have to step up to a 0w40 to regain the longevity/protection.


I have no real comments on the spun bearing debate though. I know a coworker and his brother have gone through issues with spun bearings with crate motors and such. He attributes it primarily to how much side clearance is available for the rod, not enough from the factory. If there's not enough, and you're putting high loads, you can widen the parts enough to catch. He's gotten into a habit of side clearancing all the rods every time he runs a new engine and has never spun one since. I only bring this up as in stock form, or perhaps from a variation of tolerances in manufacturing, the stock engine may not have a lot of expansion room. Some may have a lot of room, others may be on the virge. I've also seen talk of detonation as a big factor, again a source of very high forces. It's definately a dangerous event.

A stock car shouldn't do this, and this is independent on the oil. Frankly, oils these days are all good. You can't go wrong with anything out there as long as you keep it full and change it regularly. Luckily, you're well within the warranty range, so the dealer will happily throw in a new one for you. I'm still going to lean towards a simple matter of defect/variation of build tolerances of the engine. Hopefully the rebuild/new engine will fair a good deal better.
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So, I still don't know which Oil I'm going to use, hehe. And I'm not trying to bombard the board with useless information, but I feel it is good for everyone to try to make an educated decision, since most want their car to last and run forever :)

Also, most subie gurus have said that the OEM filter is great, stick with it :)
 

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WOW... Great info... So, I live in So Cal, do you think that a 5w40 would be overkill, I can be hard on the car when driving.
 
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