What oil should I use - Subaru Legacy 2018
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I would stick with 5W-30 and a maximum of 6,000 mile OCI's. I know a WRX owner in WI that has run Rotella T6 5W-40 in -20F and had no problems starting. IMO, a battery upgrade would probably be a wise move since Subaru batteries are on the weak side. There is absolutely no problem with a 9 month oil change interval but Subaru says to stick with 6 months or 6,000 miles.
The factory fill generally has higher ZDDP and moly than the dealer service fill, although FF uoa's over the past couple of years have shown this is pretty inconsistent. Some uoa's have shown GF5-like levels of ZDDP and some have shown very high ZDDP. Not sure if this is due to the lab or if Subaru is having Idemitsu tinker with the formula.
Good luck with the infotainment. The '18's have been buggy.
The factory fill generally has higher ZDDP and moly than the dealer service fill, although FF uoa's over the past couple of years have shown this is pretty inconsistent. Some uoa's have shown GF5-like levels of ZDDP and some have shown very high ZDDP. Not sure if this is due to the lab or if Subaru is having Idemitsu tinker with the formula.
Good luck with the infotainment. The '18's have been buggy.
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I live in hilly terrain a ways NW of Boston and spend a lot of weekends skiing up in the White Mountains of NH.
I park outside overnight when I go up to ski and going below -20F is certainly not unusual, so I take some interest in the cold properties of my oils.
One important thing to note is that synthetic and conventional oils of any given grade are tested to the same specs, so you're not necessarily getting better performance by picking a synth 5W30 over a dino one. But, I will say that I have noticed that there are many synthetic 5W30s that meet the cold specs by a wide margin while most dino 5W30s tend to be closer to the limits. However, an oil has to be marketed by the lowest temperature test that it passes, so one that meets 0WXX requirements has to be sold as a 0WXX and not a 5WXX.
5W30 oils are test for pumpability (MRV) at -35C and for cranking (CCS) at -30C. I generally ran conventional 5W30s in my previous vehicle and it never failed to start up North, but there were a few times when it cranked for a while and the car shook a lot and was quite noisy after it got going on really cold mornings. Subaru recommends synthetic 5W30 for my FXT and I have chosen to select oils with good CCS and MRV test results for the grade to use in winter as I have learned about the topic here and on other car sites. I haven't tried a 0W30 yet for various reasons, but I am thinking about using M1 0W30 AFE this coming winter (0WXX oils are tested for pumpability at -40C and cold cranking at -35C).
Of course, your battery is probably of much greater concern than your oil as far as cold starts are concerned. The only time I was ever stranded at work (this when I worked a good hour plus away from my house for under a year) was during a sudden snap down in temps from around 70 to the mid 30s, which revealed that my battery had deteriorated badly over the previous summer.
Your boxer 6 will be easy to pick oil for compared to my turbo 4...besides the fact that Subaru says dino is OK for your car but not mine, you don't have to worry about the LSPI issue that my car was recalled for a few years ago. I have been careful to use dexos1 Gen 2 oils lately and did my own research into LSPI and its connection to oil properties before that and chose oils based upon my findings (mostly M1 5W30s). Now LSPI resistance is included in d1G2 as well as SN+ testing, but that is only an issue in direct injected turbo (DIT) engines and basically means nothing to you.
Enjoy your new ride! I'm hoping my wife will look at a Legacy with a 6 for her next car, she really needs something with AWD given our winters and I'd like for her to have something with some kick for when I drive her car. ;^)
BTW, Rotella T6 5W40 is a very popular oil amongst those who mod their WRXs and turbo Foresters for more power, but I don't see any particular reason to recommend it for a Subie 6.
I park outside overnight when I go up to ski and going below -20F is certainly not unusual, so I take some interest in the cold properties of my oils.
One important thing to note is that synthetic and conventional oils of any given grade are tested to the same specs, so you're not necessarily getting better performance by picking a synth 5W30 over a dino one. But, I will say that I have noticed that there are many synthetic 5W30s that meet the cold specs by a wide margin while most dino 5W30s tend to be closer to the limits. However, an oil has to be marketed by the lowest temperature test that it passes, so one that meets 0WXX requirements has to be sold as a 0WXX and not a 5WXX.
5W30 oils are test for pumpability (MRV) at -35C and for cranking (CCS) at -30C. I generally ran conventional 5W30s in my previous vehicle and it never failed to start up North, but there were a few times when it cranked for a while and the car shook a lot and was quite noisy after it got going on really cold mornings. Subaru recommends synthetic 5W30 for my FXT and I have chosen to select oils with good CCS and MRV test results for the grade to use in winter as I have learned about the topic here and on other car sites. I haven't tried a 0W30 yet for various reasons, but I am thinking about using M1 0W30 AFE this coming winter (0WXX oils are tested for pumpability at -40C and cold cranking at -35C).
Of course, your battery is probably of much greater concern than your oil as far as cold starts are concerned. The only time I was ever stranded at work (this when I worked a good hour plus away from my house for under a year) was during a sudden snap down in temps from around 70 to the mid 30s, which revealed that my battery had deteriorated badly over the previous summer.
Your boxer 6 will be easy to pick oil for compared to my turbo 4...besides the fact that Subaru says dino is OK for your car but not mine, you don't have to worry about the LSPI issue that my car was recalled for a few years ago. I have been careful to use dexos1 Gen 2 oils lately and did my own research into LSPI and its connection to oil properties before that and chose oils based upon my findings (mostly M1 5W30s). Now LSPI resistance is included in d1G2 as well as SN+ testing, but that is only an issue in direct injected turbo (DIT) engines and basically means nothing to you.
Enjoy your new ride! I'm hoping my wife will look at a Legacy with a 6 for her next car, she really needs something with AWD given our winters and I'd like for her to have something with some kick for when I drive her car. ;^)
BTW, Rotella T6 5W40 is a very popular oil amongst those who mod their WRXs and turbo Foresters for more power, but I don't see any particular reason to recommend it for a Subie 6.
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Originally Posted By: 853okg
Presumably, he ain't parking overnight in the mall parking lot.
Nope but I also doubt he’ll take his car out for a ride and coming back home without stopping anywhere.
If your car has trouble starting unaided in the garage, then it will surely give you trouble starting somewhere out in the open where you don’t have an electrical power outlet available.
Presumably, he ain't parking overnight in the mall parking lot.
Nope but I also doubt he’ll take his car out for a ride and coming back home without stopping anywhere.
If your car has trouble starting unaided in the garage, then it will surely give you trouble starting somewhere out in the open where you don’t have an electrical power outlet available.
Ok. then cold start the thing EVERYWHERE and EVERY DAY and knock the >blank< out of the motor.
"warm" oil trumps 0W EVERYTIME. Nobody says you cant use BOTH.
"warm" oil trumps 0W EVERYTIME. Nobody says you cant use BOTH.
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Originally Posted By: Virtus_Probi
Of course, your battery is probably of much greater concern than your oil as far as cold starts are concerned. The only time I was ever stranded at work (this when I worked a good hour plus away from my house for under a year) was during a sudden snap down in temps from around 70 to the mid 30s, which revealed that my battery had deteriorated badly over the previous summer.
I'd agree with that. I've generally stuck with 5w-XX options over the years, year round. And we certainly have our share of bad weather. If my vehicle was always outside and unplugged on the coldest days of the year, I would reconsider.
Of course, your battery is probably of much greater concern than your oil as far as cold starts are concerned. The only time I was ever stranded at work (this when I worked a good hour plus away from my house for under a year) was during a sudden snap down in temps from around 70 to the mid 30s, which revealed that my battery had deteriorated badly over the previous summer.
I'd agree with that. I've generally stuck with 5w-XX options over the years, year round. And we certainly have our share of bad weather. If my vehicle was always outside and unplugged on the coldest days of the year, I would reconsider.
Hope he survived the four winters since the OP. I would likely just have put M1 AFE 0W-30 in it and called it a day.
Hello again,
I am surprised at myself for not replying here 4.5 years ago thanking everyone for their input. (So... thanks!!) I'm happy to report that my engine has indeed survived its 4 harsh winters so far.
Hats off to the prophetic users here who anticipated a short lived battery. It died hard on a cold winter morning of its 4th winter after a rather short trip around town. No amount of boosting helped, to illustrate how bad it was, my HUD barely lit up even while I had booster cables connected to a running car and it was reporting all sorts of random engine/transmission issues. It's interesting because it wasn't the first cold snap of the season that killed it, but rather the first short trip I made in those temps. Apparently my previous 30 minute highway commutes were just enough to top up its charge each way. Also worth noting that my car is parked outside. Oh the humanity!
The infotainment has indeed been buggy, even after the dealer updated its firmware it would sometimes not boot up, requiring a complete power cycle of the entire car. Other than that, various parts of the interior trim makes lots of jiggling/rattling sounds as I drive. A bit disappointing considering this is a "sub-luxury" car but oh well. At least the engine appears to be rock solid. But I digress...
Probably to the community's chagrin, after my OP I opted to operate at "minimum OEM warranty compliance mode" and opted for conventional 5w30 changes every 6 months (since I never surpassed 6k miles during those periods.) I would get whatever's on sale/the cheapest, as long as it meets rating, so I've fed my car a variety of brands like Pennzoil, Quaker, Castrol, but mostly Canadian tire motomaster branded dino (apparently it's made by Shell.) As for filters I predominantly used Motomaster OE Plus (apparently similar to Fram TG,) or better.
I am legitimately curious if any measurable wear occurred on my engine as a result of this. I haven't done any UOAs but would doing one now give me any useful info? Or will it only show the wear that occurred since my last oil change? I am supposed to replace my spark plugs soon, so if I'm feeling up for it I might measure cylinder compression while I'm at it. Anything else I can check to gauge engine wear?
As for the future, since my warranty will be up soon, I plan to go for 6K OCIs, regardless of how much time elapses, using a "standard" full synthetic 5w30 like the Pennzoil Platinum (or Motomaster synthetic lol.) Reading around here I hear the 3.6 is very easy on oil. I am aware of at least one user here that has been able to pull off a 10K OCI with this engine no problems. But would love to hear any other comments or pointers regarding this.
I am surprised at myself for not replying here 4.5 years ago thanking everyone for their input. (So... thanks!!) I'm happy to report that my engine has indeed survived its 4 harsh winters so far.
Hats off to the prophetic users here who anticipated a short lived battery. It died hard on a cold winter morning of its 4th winter after a rather short trip around town. No amount of boosting helped, to illustrate how bad it was, my HUD barely lit up even while I had booster cables connected to a running car and it was reporting all sorts of random engine/transmission issues. It's interesting because it wasn't the first cold snap of the season that killed it, but rather the first short trip I made in those temps. Apparently my previous 30 minute highway commutes were just enough to top up its charge each way. Also worth noting that my car is parked outside. Oh the humanity!
The infotainment has indeed been buggy, even after the dealer updated its firmware it would sometimes not boot up, requiring a complete power cycle of the entire car. Other than that, various parts of the interior trim makes lots of jiggling/rattling sounds as I drive. A bit disappointing considering this is a "sub-luxury" car but oh well. At least the engine appears to be rock solid. But I digress...
Probably to the community's chagrin, after my OP I opted to operate at "minimum OEM warranty compliance mode" and opted for conventional 5w30 changes every 6 months (since I never surpassed 6k miles during those periods.) I would get whatever's on sale/the cheapest, as long as it meets rating, so I've fed my car a variety of brands like Pennzoil, Quaker, Castrol, but mostly Canadian tire motomaster branded dino (apparently it's made by Shell.) As for filters I predominantly used Motomaster OE Plus (apparently similar to Fram TG,) or better.
I am legitimately curious if any measurable wear occurred on my engine as a result of this. I haven't done any UOAs but would doing one now give me any useful info? Or will it only show the wear that occurred since my last oil change? I am supposed to replace my spark plugs soon, so if I'm feeling up for it I might measure cylinder compression while I'm at it. Anything else I can check to gauge engine wear?
As for the future, since my warranty will be up soon, I plan to go for 6K OCIs, regardless of how much time elapses, using a "standard" full synthetic 5w30 like the Pennzoil Platinum (or Motomaster synthetic lol.) Reading around here I hear the 3.6 is very easy on oil. I am aware of at least one user here that has been able to pull off a 10K OCI with this engine no problems. But would love to hear any other comments or pointers regarding this.
