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Argument for thicker oils

5972 Views 95 Replies 27 Participants Last post by  s2mikey
Savage Geese has a video on YT about the perils of direct injection.
He says the problems that arise are deposits building up on the backside of intake valves, in part due to evaporated motor oil fumes and blowby products, not being washed off by port injection. At about 15:50 in the video he starts discussing why its not good to run the thin oils due to their high evaporation rate. He suggests that 0w-16,0w20, 0w-30 are best replaced by 5w-xx oils because they generally are less evaporative.
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I'm seriously considering skipping my free oil changes -- even though they've noticed me that my first freebee is set for 3750 miles, which is good to see -- because they'll surely use 0-20. I don't see ever using 0 weight in this car. PS I did DIY oil change at 1K miles with 5-20.

I have a bunch of 0-20 in my garage and will use it up on my 4Runner, which is not picky! But gonna stop using 0 weight on that thing too once my 0-20 is gone.
Yeah man you wan a dump that factory oil asap.
Personal experience.

During the winter my BRZ was running 0w20, since I don't have the factory oil warmer anymore, I let the car warmed up for at least 5 mins before I drive it to work. It burnt half a quart of oil during the 2000 miles I have driven it during the winter.

Now I switched it back to 5w30, the dip stick hasn't shown me I have burnt a single drop of oil 🤷‍♂️. Go figure right? Lol
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Once and for all, this is a good video about why manufacturers are being forced to run lower viscosity oil.

New modern engines have extremely tight clearances. Using too thick of an oil will prevent the oil from going in between all the moving parts.
Shouldn't tight clearance means less efficient on making power? Since more friction is created under load. And I think FA engines have looser clearance than the old EJ, and the old EJ was recommended to run 5w30.

+ by no means jamming 20w50 into your engine is a good thing. However running 0w20 is strickly an economy thing.

And im not discrediting the liquimoly guy at all, he probably knows more than I do. And he probably knows what to say on camera more than I do as well.
My biggest question.

Can we please define "colder climate"?? Like 32°F(0°C) is pretty damn cold to me. But according to the viscosity chart, that is not cold enough for 5w30.
Idk if you guys missed the point the video is about 22 wrx 😅. Not brz/86, pretty sure fa24dit sees more heat than fa24d. Makes sense if he wants to run 5w40 if he is at somewhere the spring is picking back up.
Nah. That is too thick for daily use. He will be doing more harm than good. Any wear he thinks he is preventing under high temps is being offset by the extra wear occuring during warmup. The difference being that will happen every single time the car gets started and that "extra super high temp protection" he thinks he needs will probably occur for a total of 10 minutes over the course of a 5000 mile oil change interval. I could understand using a 0w40 for a long hard track session then dumping it immediately after for something more reasonable. But not as a daily use thing. Its not an air cooled Harley.
Interesting take. This is what 2015 wrx FA20DIT owner's manual asked for.

Unless the FA24DIT internals really changed (bearings tolerance, piston rings tolerance, turbo design, oil galley channels), I don't see why subaru decided to ditch 5w40. Knowing how cheap subaru is, i highly suspect nothing changed, beside bore size and conrods. Or 5w40 conventional oil is that much the same as 5w30 synthetic oil, I'm not the expert, you are.

Btw dumping oil after track days is a huge waste, did a few oil analysis after a few hard events for them to tell me the oil was absolutely okay.

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I will agree that quality oil does not need to be dumped after reasonable track use. I say to dump it not because its bad, but that it is definitely overly thick and excessive for daily street use. Unfortunately, Subaru is not a manufacturer I deal with and in all honesty I dont know nearly as much about them as I do most other engines. I dont know what, if any changes were made to their engines when making the change to thinner oil. But in general most manufacturers did make changes. Things like coated cylinder walls rather than sleeves, tighter ring gaps, new ring\bearing materials, oil passage sizing all were part of this thin oil and reduced friction initiative. I wonder what the reliability track record looks like before\after the change. I mean EJs were never reliable. Was there any more\less bearing\rod failures when oil weight changed?
EJ engines' oiling failures usually came from cracked pickup tube, oil sloshing during track use, and oil thinning out at heat. All can be fixed under aftermarket mods, after that in stock form they are plenty reliable. Problems came in when people turned up the boost, and piston ringslands start cracking, or you had the good ole joke about their single layered head gasket (which was fixed with a multi layer steel head gasket, even though subaru never made a recall about it)

Spinning bearings happened when folks lugging the engine on highways. (Trying to pass traffic at high gears while trying to build boost). But other than that, many lasted 100k+ miles as I can recall. And they were all running 5w30 / 5w40 😂. That's why I said, it made no sense for subaru shoving 0w20 to our face, when their tighter tolerance EJ engines were running 5w40 all seasons. Bruh a turbo engine runs 0w20 is kinda risky business in my opinion.
And I highly doubt a lot of sti owners don't run 5w40 when they bought their VA STI. They should know what they are getting into, and have plenty of research.

But like I said, ringlands failures were more common in EJ25.
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