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Premium Member
'01 2.5RS sedan, silver
25 Posts
Discussion Starter #1
I fought the temptation to wake a dead thread lol

I just wanted to add my 2 cents

This is a copy from what I was going to post.

The red text are my new additions.

This discusses oil in general.

As a former mechanic, former auto-parts retail manager, and a current polymer chemist

NO, using X brand synthetic oil is not why you spun a bearing

NO, Synthetic oil isn't a scam

Conventional oil has a greater change in both lubricating properties and viscosity in a given service interval than comparable synthetics would.

NO, Synthetic oil isn't worse at transporting waste away from critical areas. (not really sure what the logic is of this assertion).

YES, there are levels of certain additives both inorganic and organic. These vary depending on which standard the oil is meeting.

OIL change intervals? Use what the dealer says unless you are built... Then check out this video [STi High Power and Maintenance]. IF you want to know more about which weight oil then ->[Which Oil Do I Put in my Subaru WRX?] by buff productions. (not sure about the rules on links).

These videos aren't one-stop-shop guides but the reasoning is spot-on.

You will have to use your own judgment and the expertise of others

NO, synthetic engine oil will not smoke your old engine... being old is was smoked your engine. This is the anti-vaxxer argument of the car world.

BUT, if your engine was from ye-olden-days when we didn't use detergents in oil... then that could be an issue. Even modern conventional oil uses detergents UNLESS otherwise noted(30w, non-detergent oil for mowers as an example).

YES, AT fluid that isn't changed in proper intervals will have this issue... but just service your damn car.

OIL BRAND, probably, doesn't matter as long as you are using a name brand.

Why do I think that? Some fields in polymer chemistry involve making some of these cleaning and viscosity modifying additives. I, therefore, have a decent comprehension of these species.

Generally these brands will use the same class of polymers unless there is a specific requirement that one brand meets and the other doesn't (Chevy had/has the DexOs or whatever it's called but now everyone seems to meet that standard)

What do I use?
Castrol Syntec (EDGE or whatever dumb-shit name they use now)

Royal Purple
Mobil 1

depends on which is on sale.

Oil change interval?

I do so as prescribed by Subaru. BUT, I know that syntec is good for what the bottle says.

Take note: most oil test are sponsored so try to find one that is independently performed before you see an ad and go "wow, X brand is clearly better than Y".

A lot of oil test may use ICP-MS or ICP-OES instruments. Of which, I am familiar with ICP-OES. These are great for looking at inorganics but the organic additives like polymer friciton modifiers are not going to show up in these test. Make sure you ask what you will get to see if you want to compare oil on your own.

Premium Member
'01 2.5RS sedan, silver
25 Posts
Discussion Starter #3
Yeah I've always liked Castrol products.

If you service it regularly then just about any oil will work.

It's not like engines were exploding until we developed synthetic oil and it's not like they started to after we switched.

Synthetic oil is objectively better. But, that isn't to say that conventional isn't perfectly fine.

I would argue that blended oils are pointless but ... eh, whatever floats your boat. lol

95 Coupe, 95 Sedan & 95 Wagon
12,326 Posts
Oh I was just dding that in support!

Also, I honestly think a part of developing synthetic is for the masses of non-car people who go way to long without changing their oil because they don't care, know better, time, money, etc.

I just saw Google is really pushing a translator program where you can speak English and it will translate in 27 languages for now. That just tells me I don't have to learn a lick of that language anymore, Google will do it for me. Thanks! I can go be lazy again and scroll on IG and spend money on useless things. +1 for Corporations LOL

Anyways, keep it lubed!
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