Legacy Engine

There's one thing that I wonder about with my old Legacy, is how come the engine despite having 271.000ks on the clock, still burns no oil. I mean why doesn't it? Does it have special type of rings in it or something. I would expect it, or any high mileage engine to be burning through it by now.

Maybe someone can enlighten me on the matter?

The car that I replaced it with, a brand new Mazda3 has been burning oil since day one. About half a liter per 10.000ks. I complained about it, but was told that it was within Mazda's guidelines. I complained further about how a brand new car in my opinion shouldn't be burning any oil at all. One of their mechanics told me in confidence that they have found that all the new ones are, and that they think it is due to the super thin oils that they are using these days.

Looks like I'll just have to wear it. Maybe it's time to bring on the electrics.

I wouldn't even say it's a Subaru specific thing, I've had a bunch of Subarus, including one with 190k that uses a quart every 2000 miles or so, but then another with 230k that never consumed a noticeable amount. I'm not even going to mention the mini I had that burned a quart of oil every 500 miles haha. I think a lot of it comes down to maintenance, engine break in and overall how it's driven.

EPA regulations are forcing all the car companies to search for fuel efficiency in increasingly silly ways. One of these is running 0w20 oil. This oil passes rings no matter what design or materials are used. It also passes valve stems and burns off there as well. The only solution is to use an oil that is capable of filming and shearing in a way that makes sense for internal combustion engines and accept the .04% reduction in fuel efficiency. Gains many orders of magnitude better could be had by simply not producing 4400 pound cars and 6500 pound trucks for the average person to use daily.

I wouldn't even say it's a Subaru specific thing, I've had a bunch of Subarus, including one with 190k that uses a quart every 2000 miles or so, but then another with 230k that never consumed a noticeable amount. I'm not even going to mention the mini I had that burned a quart of oil every 500 miles haha. I think a lot of it comes down to maintenance, engine break in and overall how it's driven.

Yes I think you could be right, in that not everybody looks after their cars the same way.

EPA regulations are forcing all the car companies to search for fuel efficiency in increasingly silly ways. One of these is running 0w20 oil. This oil passes rings no matter what design or materials are used. It also passes valve stems and burns off there as well. The only solution is to use an oil that is capable of filming and shearing in a way that makes sense for internal combustion engines and accept the .04% reduction in fuel efficiency. Gains many orders of magnitude better could be had by simply not producing 4400 pound cars and 6500 pound trucks for the average person to use daily.

Yes I think you're on to something there, in respect to the newer cars burning oil these days. I am going to start using a thicker oil myself in my Mazda, after noticing the dealership was putting in a thicker oil themselves when it was going in for servicing when it was still under warranty.

This is a tricky path to take. In order to keep reasonable oil pressure the main/rod/cam bearings have tighter clearances for the 0w20. If you then switch to a thicker oil you risk too much pressure popping the bypass and reducing flow throughout the engine. If the dealer is putting in 10w30 in place of 0w20 then they did it first so trying it won't be that bad. I wouldn't go any thicker without talking to an engine builder with decades of building and race experience. The real solution is for the OEs to stop building these silly engines and go back to what has worked extremely well for the last 120 years.

This is a tricky path to take. In order to keep reasonable oil pressure the main/rod/cam bearings have tighter clearances for the 0w20. If you then switch to a thicker oil you risk too much pressure popping the bypass and reducing flow throughout the engine. If the dealer is putting in 10w30 in place of 0w20 then they did it first so trying it won't be that bad. I wouldn't go any thicker without talking to an engine builder with decades of building and race experience. The real solution is for the OEs to stop building these silly engines and go back to what has worked extremely well for the last 120 years.

Well when I say a thicker oil I mean 5w30. That's what the dealership changed to, from the 0w30 that it had in it from Japan. When I asked about the change, they told me that the thinner oil was ok when it was running in. But here in NZ they said wasn't needed as our Winters are not as cold as Japan. Not in the North Island anyway. So I thought ok I'll be using 5w30 from now on.

It's funny when you say be careful using the thicker 10w30. It reminds me of a time back in my younger days in the mid seventies when 30/40 was the only oil there was. It was horrible thick gluggy stuff. The damned cars wouldn't drive unless they were warmed up for 10-15 minutes first. Thank God we don't have to do that anymore.

Sounds good. That is a minimal change on the cold and hot weights.

 

I expect NZ is somewhat like where I grew up in MI/US. All that water just a little way off helps buffer the temps in the winter. At similar latitudes in the middle of the US, -25F is common, but in MI the Great Lakes, that don't freeze, heat the air back up and we rarely see below 0F. But all that water adds up to more snowfall.