Going synthetic at next oil change. 0w20?

pilot1226pilot1226 Member Posts: 166
As the title suggests, I am changing over to synthetic oil at my next service which also happens to be the 30k. I noticed my manual and my oil cap calls specifically for 5w30 which is very standard for conventional oil. (I have an '11 OB 2.5i). Newer models call for the new Subaru rebranded synthetic.

Is it okay to put 0w20 like a Mobil 1 into the car or should I just find a 5w30 Motul or comparable synthetic to run it.

I plan on going 5k before oil changes which will probably take about 6 months. I check my oil regularly (every 2 weeks sometimes more) so if there is any burnoff from 0w20 I should catch it and add some before it becomes a problem.



  • bpeeblesbpeebles Member Posts: 4,085
    edited September 2013
    Certainly you can (and perhaps should) change to synthetic oil. However DO NOT alter the 5w30 viscosity. (Castrol is my preferred oil - Mobil1 is *not* a true group5 synthetic.)

    Were you aware that your 2011 SHOULD be running synthetic anyway? Why would you be running anything else?

    Also, I believe your 2011 calls for 7500 mile OCI (Oil Change Interval) so 5000 would be just fine. Again, why waste your money and envrionment by changing perfectly good oil too soon?

    The clearances within the engine are DESIGNED for the specified oil-viscosity. Thinner oil (0w30) may allow metal-to-metal contact between the moving parts.

    Besides, most engines which call for thinner oil only do so to enhance econemy.... (less pumping-losses within the engine)...the thinner oil ALWAYS provides less engine-protection due to its tendancy to get squeezed out from between the metal parts. Again, if the engine is DESIGNED for the thinner oil, it is OK.
  • chuck1chuck1 Member Posts: 1,405
    edited September 2013
    The 2.5 loves conventional oil. The tolerances of these motors are not as tight as most motors. I have a 2012 Legacy 2.5 and the manual calls for conventional oil.

    Your vehicle is designed to use 5W-30
    conventional motor oil, however 5W-30
    synthetic may be used.

    I would also recommend spending time over at bobistheoilguy.com

    The conventional wisdom with all oils being better than ever that your motor is not going to last any longer (under normal driving conditions) using conventional over synthetic, unless of course the manual calls for synthetic.
  • bpeeblesbpeebles Member Posts: 4,085
    edited September 2013
    (chuck1) I agree that using synthetic oil does NOT 'protect' any better than a good dino-oil changed regularly.

    HOWEVER: Lets not forget some reasons why synth-oil may be called for:
    1) Cold-weather starting (if you start your car in sub-zero temps.)
    2) Reduced coking (Turbochargers will actually burn dyno-oil and leaving abrasive carbon deposits which grind the bearings)
    3) Extending drain-intervals. (My last car went over 160K miles with 10K mile OCI...oil was $10 per liter and shipped from France)
  • winter2winter2 Member Posts: 1,801
    edited September 2013
    I have been using synthetic oils since the early 1990's and here is what I have observed.

    1. Synthetics are superior to conventional motor oils. Newer engines, especially four cylinder engines are now making the same horsepower as some V-6 engines made only a few years ago. These four cylinder engines run hotter and synthetic oils are far more tolerant of heat than conventional oils.

    2. Engines now are more complex than earlier versions, especially the valve trains of which most have some form of variable valve timing. That stuff needs to be kept spotless in order that it work properly. Synthetics do a better job of keeping an engine clean than conventional motor oils.

    3. Synthetic flow better when cold and have better viscosity at all temperatures versus conventional oils. Also, most synthetics are more slippery thus improving fuel economy a little bit.

    4. As advised by others, use a 5W-30 and not a 0W-20. If it calls for a 5W-30 use that. I have a 2013 Outback with the FB25 engine and that calls for a 0W-20 synthetic oil.

    5. As someone said, Mobil 1 is not a great oil any longer. I am using Amsoil mid-grade synthetic (XL) and with shipping and tax is still cheaper than many other name brands, if you are a preferred customer.

    6. The OCI for me is 5000 miles. I would not do that with a conventional oil as it simply would not hold up for that distance.
  • chuck1chuck1 Member Posts: 1,405
    Today's conventional wisdom says that your motor will not last any longer with synthetic vs. a good conventional oils. There are many fleet buyers that use recycled oil that performs just fine under conditions most would consider extreme.

    If you did an oil analysis you would learn changing synthetics at 5,000 miles are a waste of money.
  • chuck1chuck1 Member Posts: 1,405
    Winter 2

    Go down to used oil facts-

    Read what the California Highway patrol uses-
  • winter2winter2 Member Posts: 1,801
    edited September 2013
    If I were to use a conventional oil, I would be changing oil every 2500 miles. As to using recycled oil in fleets, those fleets are parts of businesses and they can write off wear and tear on their fleet whereas the average person cannot.

    In most fleets, they purchase the cheapest vehicle possible and the engines in those vehicle lack much of the sophistication found in the Subaru boxer engines, so the use of recycled oils is no big deal to them.

    I have done oil analysis and yes, I did have a few thousand miles left on the oil, but I am not going to take it to the end of the oil's life an find out what happens later.

    BTW, I recycle all of my used oil.
  • pilot1226pilot1226 Member Posts: 166
    After reading up on the bobistheoilguy website I've come to a reasonable conclusion that I'm going to run around 6k on the Motul 5w30 I'm running.

    I'm sure the oil can last longer, but at that point we're talking around 5-6 months of driving, maybe less since it's the winter season, and for me it becomes more a question of the integrity of the Subaru filter on there at that point.

    I can stomach the extra cost for the synthetic oil changes considering I'm doing them twice a year per car.

    Especially in the winter time, where I've read lots of documentation that the synthetics result in a faster startup and more importantly faster lubrication in the colder months.

    Thanks for the input on the thread. I'll stick with the Motul for now. I've heard some mixed reviews about Mobil 1 having a tendency to burn off in the boxer engines.

    As a matter of good housekeeping, I'm in a habit of checking the oil level and tire pressure about once a week for both vehicles. It's easy peace of mind that takes literally 5 minutes to do. If that.
  • fibber2fibber2 Mid Hudson Valley, NYMember Posts: 3,786
    Recycled oil: In normal use, oil gets contaminated with a number of metals found in the modern engine. Additives & modifiers separate out and are either burned off or are oxidized by the presence of air, daily condensation moisture or blow-by combustion gases. Longer chain molecules crack. In time, the oil is considered worn out. However, I’m sure that the worst used motor oil is probably more suitable for immediate use than the best sweet crude. If used motor oil is put thru a proper refining process, it has the potential to be as good as, if not better than new. At issue, of course, is who is doing the refining, and what’s their control plan like? Frankly, I’m not yet feeling inclined to gamble with my motor.

    I’ve always run M1 synthetic (5W-30) in my OBW, as I figured it was better than conventional, and really not all that much more expensive. So bang for the buck, I view M1 is pretty good stuff. Not as good as some premium products, but it works fine in my use case. I only drive about 9k per year (111K miles in 12 years), and change oil every 6-7 months or so. It’s more about the drive cycles and weather extremes over that time period than total miles or months. And the belief (right or wrong…) that synthetic just might hold up a little bit better while circulating a little bit faster on those near zero degree days.
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130

    I would stick with the 30-weight. 0w-30 vs. 5w-30 changes the pour point, so 0w-30 is good for colder climates (regularly drops below -20C or ~-10F), but operating viscosity remains the same. Optimal OCI is dependent on the oil. I guarantee you the oil you're running is fine at a 5/6K OCI.

    If you go with extended OCIs, synthetic oils will perform better than standard. But, 6K is not an extended OCI. "Extended" is anything over the interval recommended by the manufacturer (7,500 miles). I run annual oil changes on my vehicles, which is generally 10-15K intervals. The cost of the oil change (in lubricant and filter) is $50. I also pull an oil sample and have it analyzed ($28 including mailing costs) so that I know the oil is performing satisfactorily under that OCI, there are no problems developing in the engine (an important aspect given the EJ25's propensity to eat head gaskets), and, on the first three changes, I also do a TBN (total base number - costs an extra $10) to determine the safe operating interval of my particular brand/grade of oil. The TBN represents the oil's buffering capacity against acids that are created as part of the normal combustion process, so you definitely don't want that capacity eroded.

    I have determined that my oil, when operated in my EJ25 SOHC engine, is operating effectively up to 16,000 miles without worry. I could probably push it a little further, but I see no sense in doing so as I have yet to exceed that number in a single year (TBN was 1.3 on the sample I sent in with just over 16K miles, and you want your TBN >1). So, I spend $80-90 a year in oil changes on each of my daily drivers, but I only have to change my oil once. That's a good compromise when multiple oil changes a year would mean lying on my back on an ice-packed driveway at sub-zero temperatures (sometimes VERY sub-zero!). I've been there before, so no thanks. :-D
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • bpeeblesbpeebles Member Posts: 4,085
    edited October 2013
    I admire that you seem to actually TESTED your oil to determine its condition.

    I also prefer high TBN oils. (Total Base Number) Which is a measure of an oils' PH capability of neutralizing acid caused by combustion by-products.

    One of the longstanding reasons why Subaru engines in particular need attention to the oil is the EXTREMELY small oil-filter....Heck most riding-lawnmowers have larger oil-filters!!!

    This small filter has a limited capacity to contain contaminants. Hence, the small filter goes into BYPASS mode within 8K miles. At that point, the oil is just circulating around the engine without be filtered.

    Due to the engine-design of the "EJ" engine... the oil-filter is located very close to the exhaust-pipes. Although a larger filter will physically fit... it is known that using a larger filter tends to 'cook' the oil due to the hot exhaust.

    The only reasonable way to extend oil-changes on the "EJ" engine is to change the filter half-way thru. (and replace the lost oil)

    This is one reason that the new "FB" engine has the oil-filter located on the TOP of the engine.
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    edited October 2013
    I was definitely concerned about the tiny oil filter size (even smaller in overall capacity than the previous EJ filter. Even though they are cross-compatible on the cars with the older exhaust routing design, the new exhaust format makes the larger ones unfittable) when I first bought this car. Therefore, I was sure to run my first extended interval such that I could test for evidence of reduced filter performance.

    On my first oil change, I sent in a sample mid-cycle (at 7,500 miles - car had ~10K miles) to have it analyzed. It came back looking very well, so I went ahead and let the oil stand until the July 4 holiday (that's my standard weekend for auto maintenance). At that point, it had ~11,000 miles and it was changed along with another oil sample being sent in for analysis.

    In both cases, TBN and particulates (the part that the filter handles) were excellent. I'm interested in learning more about your concerns (after all, this is an engine that I want to perform well over a long while to come!), however, so if you are interested, I recently had my sixth analysis performed on this car and it catalogs the results since the car was essentially new. I am happy to share this PDF document with you for further discussion.

    I also want to reiterate that the intervals I have established as being effective for my car is only applicable to my scenario with the current parameters (eg., engine, oil, filter, and overall operating environment). I would never advocate that anyone approach the miles I run without establishing safe parameters within their own scenario first.
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • bpeeblesbpeebles Member Posts: 4,085
    It sounds as if you have 'done our homework' and are confident regarding your OCI decisions. Not everyone takes the time to do the oil-testing to get to that confidence-level. This is why, for the rest of us, the manufacturers recommend OCIs based on their own testing.

    Most people do not realize that, for one reason or another, they fall into the 'severe service' category and should change at the shorter OCI. (Short trips, Cold weather, dusty conditions...etc)
  • KCRamKCRam Mt. Arlington NJMember Posts: 3,516
    Most people do not realize that, for one reason or another, they fall into the 'severe service' category and should change at the shorter OCI. (Short trips, Cold weather, dusty conditions...etc)

    One thing Chrysler did back in the mid 2000s was rename their maintenance schedules. Instead of normal and severe, the "severe" became "B" and the normal was renamed to "A", with a note that most vehicles fell under B. More recently, they dropped the light maintenance schedule altogether and just list what used to be the severe/B schedule for all vehicles and driving styles.

    KCRam - Pickups/Wagons/Vans+Minivans Host
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