Anyone else using conventional w/ 3.6R

Was thinking of switching to synthetic... Been doing conventional for past 4 years.....

does Subaru recommend it? if no, do not change. I drive many a car well over 200K on regular oil. Changing it on time is the important part

Id have to look it up to be certain but I believe 3.6 calls for synth, not conventional.

Mine has had a steady diet of Amsoil since its first oil change.

 

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Was thinking of switching to synthetic... Been doing conventional for past 4 years.....

 

I've been using synthetic from day one. The following article claims synthetic is "required' in some Subaru's ??? ... I'm not sure that is totally correct ... but it's what I prefer to use. When I first bought my car 3 years ago, my local dealer did not stock synthetic, which wasn't a problem for me because I brought my own oil ... but not long after that they started stocking it ... so I don't know if it was a change in Subaru oil policy or not ???

 

https://www.patriotsubaru.com/synthetic-oil.htm

My 3.6R got conventional every 6k miles. Which is what was listed in my manual.

Car served me well.

Thanks for the replies. I'm gonna stick with Conventional. In this day and age it's rare for a manufacturer to recommend conventional, so they must have done it for a reason. Being naturally aspirated it's not stressed like a turbo or revved to death like a 4 banger..

I have been using M1 since the first oil change but I am considering a switch to conventional next time. Just can't justify synthetic with the 6K mile/6 month change interval required to keep the warranty valid.

It simply astounds me how some people steadfastly refuse to consult the Owners Manual. The authoritative answer to the OP's original question is right there in black & white.

Either is fine for the 3.6R according to the owner's manual. I bought mine used and it had conventional until the first oil change under my ownership at about 24k. It burned maybe a half quart of oil before the next oil change, but after that I haven't noticed any burning of oil so maybe it was just that transition period. I didn't notice a difference in how the car runs before and after, but I buy oil on sales so it's <$20/yr more to run synthetic vs conventional, and that's worth it to me living in the cold Wisconsin climate.

It simply astounds me how some people steadfastly refuse to consult the Owners Manual. The authoritative answer to the OP's original question is right there in black & white.

 

Can you tell me what your manual says. I have consulted my owners manual and whilst it certainly specifies a grade of engine oil, it does not specify either conventional or synthetic.

 

Mine states ....

 

" Always use the Subaru approved engine oil. For further details we recommend that you contact your Subaru dealer. If the approved engine oil is unavailable, use the alternative engine oil described on the next page ..."

 

On the next page that they refer to, it merely mentions the necessary API or ILSAC certifications.

 

I don't know about you, but I would hardly call that a definitive or authoritative answer to the question of whether conventional or synthetic oil is the "approved" option or not. And leaving it up to the discretion of a dealer would again not be authoritative from my experience, because if you rang 6 dealers and asked them the question, I doubt very much if you would get a unanimous answer.

Don't overthink this. 5w30 is 5w30. Synthetic just breaks down slower and performs better at low and high temps. You can choose either.

With the frequent changes required for warranty, synthetic may well be overkill in moderate conditions.

 

For the 2.5, synthetic is required -- I've never seen the 0w20 in mineral. With my final change before warranty is up, I will likely move to a European formula or Amsoil and change at a 10,000 mile interval, using WIX filters.

Can you tell me what your manual says.

 

From my 2018 Owner's manual, for 3.6L models. Page 12-6

 

"Your vehicle is designed to use 5W-30 conventional motor oil, however 5W-30

synthetic may be used for optimum engine performance.

*: If 5W-30 synthetic oil is not available,

10W-30 or 10W-40 conventional oil

may be used if you need to add oil.

However, you should change to 5W-30

synthetic or conventional oil at the next

oil change."

Can you tell me what your manual says. I have consulted my owners manual and whilst it certainly specifies a grade of engine oil, it does not specify either conventional or synthetic.

See attachment, from the 2015 Legacy/Outback Owners Manual (North America).

 

And leaving it up to the discretion of a dealer would again not be authoritative from my experience ...

Sad, but true. Most dealer personnel don't read the manuals either, and many will just make up an answer rather than admit, "I don't know." Human nature, I guess.

OM_12_p5-6_Engine_Oil_Specs.pdf

Edited August 29, 2019 by ammcinnis

From my 2018 Owner's manual, for 3.6L models. Page 12-6

 

"Your vehicle is designed to use 5W-30 conventional motor oil, however 5W-30

synthetic may be used for optimum engine performance.

*: If 5W-30 synthetic oil is not available,

10W-30 or 10W-40 conventional oil

may be used if you need to add oil.

However, you should change to 5W-30

synthetic or conventional oil at the next

oil change."

 

Thanks for that ..... that is what I would call definitive. My 2016 manual, for what ever reason, does not say that. Yesterday I actually rang one of the local dealers nearby and asked the question regarding what is the recommended engine oil for my vehicle and why it wasn't stated in the manual and he was surprisingly honest and said "because they want you to ring the dealer."

Don't overthink this. 5w30 is 5w30. Synthetic just breaks down slower and performs better at low and high temps. You can choose either.

 

Whilst with respect I think your list of benefits of Synthetics is pretty short (refer the link below) ... I agree that it's not worth stressing over the use of conventional or synthetics, provided regular oil changes are carried out.

 

Like with most issues concerning my vehicle, I have done the research on engine oils and made up my mind from the beginning what my preference was going to be .... I just found it a bit odd that my owners manual (unlike the 2018 version as tumbleweed has pointed out) is strangely silent on the possible options. If I was going to be a bit cynical I might suggest that the reason they do it is perhaps because they want their smaller dealerships not to have to carry both conventional and synthetic, and therefore these dealerships can just promote conventional. As I posted previously, at my very first service, my dealership did not carry synthetic ... but now they do.

 

https://www.idrivesafely.com/defensive-driving/trending/synthetic-oil-vs-conventional-oil

From the 2019 Owners Manual, Verbatim...

 

NOTE

Synthetic oil of the grade and viscosity

noted in chapter 12 is the recommended engine oil for optimum engine

performance. Conventional oil may be

used if synthetic oil is unavailable.

Edited August 30, 2019 by johnm304

Dealer just put conventional oil in my 3.6R. (Far as I know there are very few cars that require synthetic.)

Dealer just put conventional oil in my 3.6R. (Far as I know there are very few cars that require synthetic.)

 

I guess that depends on your definition of "few" and "require."

 

The following is taken from this link https://www.angieslist.com/articles/synthetic-motor-oil-better-your-car.htm

 

" .. Whether or not synthetic oil is right - or required - for your vehicle first depends on what type of vehicle you drive, mechanics say. New and late-model vehicles from European makes such as BMW, Volkswagen, Mercedes-Benz and Audi typically require the use of full synthetic oil. Bell adds that certain new vehicles from Subaru, some Hondas and Toyotas (typically hybrids), and some high performance cars also require synthetic oil. ..."

 

And when the recent post from Johnm304 is taken into account .... if owners "require" optimum engine performance they should use synthetic.

 

Again, I repeat, I am not necessarily a "synthetic oil pusher" ... but with respect, I think the statement in your post is a bit too general.

From the 2019 Owners Manual, Verbatim...

 

NOTE

Synthetic oil of the grade and viscosity

noted in chapter 12 is the recommended engine oil for optimum engine

performance. Conventional oil may be

used if synthetic oil is unavailable.

 

I just saw this yesterday in my manual. For what it's worth the dealer used synthetic in my oil change today but when we bought the car 5 months ago they made very sure to tell us that conventional was what they recommended. Bit of a disconnect there. I don't care - I'd rather have synthetic.

I just saw this yesterday in my manual. For what it's worth the dealer used synthetic in my oil change today but when we bought the car 5 months ago they made very sure to tell us that conventional was what they recommended. Bit of a disconnect there. I don't care - I'd rather have synthetic.

 

This is exactly the problem that myself and ammcinnis commented on in an earlier post ... the fact that certain dealerships either don't read the manual ... or for their own self serving reasons, deliberately choose not to follow the manual. Again I will say that the overiding factor in most cases is to ensure that owners do the specified regular oil changes, rather than the actual type of oil used .... but I agree with your comment that there is a bit of disconnect there.

I don't have much to add (aside from a huge quote), but I wouldn't expect owners manuals and fluid recommendations to be the same in owners manuals around the world. Different climates and different oil basestock availability may affect what oils are available, and what automakers recommend.

 

This came up years ago with 5w-20 and CAFE on BITOG, but I think things have changed now. I know I'm going off topic a little, but I think it's interesting info, even if it's 13 years old.

 

"These recommendations of different weight oils for the same engine in different parts of the world has to do with the different oil basestock supplies around the world. Grp I basestocks are still predominately used outside of North America (Canada/US) -- and even in Europe. There is comparatively very little Grp II supply of basestocks outside of NA.

 

A couple of new Asia-Pacific plants that produce GrpII/III�s (and in Europe) have come on stream in the last couple of years, but before that there was virtually no supply of Grp II�s in Asia or Europe. Even then, these Grp II plants can only supply a very small fraction of the base oils needed if areas like Asia wanted to switch from Grp I to II basestocks for their motor oils. To put this in perspective, in 2003 about 75% of the world Grp II supply was in NA, and we just have enough Grp II supplies to meet our demand for motor oils. Some independent producers were worried about the supply of Grp II�s to meet the new GF-4 spec�s, because Grp II�s would basically be required to meet the NOACK volatility requirements and Grp I would basically almost be shut out completely. For the rest of the world, they have to use mostly Grp I�s or synthetics -- no choice. In Japan (2003) 84.4% of the oil basestock supply was Grp I -- 7.4% Grp II.

 

There is simply no way to make a quality 5w-20 oil from a Grp I that is going to hold up very long in an engine. Without any supply of Grp II hydrocracked oils, the only way to make a good 5w-20 would be to use synthetics -- Grp III�s and up. But then, if a manufacturer spec�s 5w-20 outside NA, they would basically be forcing these people to use synthetics -- and the cost issue comes into play. The average motorist will balk at the cost of synthetics.

 

Ideally, one wants to use a thinner oil like a 5w-20 or 5w-30 over a 10w40 because of fuel mileage and likely better oil circulation, but the problem is that thinner basestocks don�t hold up as well a thicker ones -- particularly with regard to NOACK volatility, and I�d imagine somewhat with regards to thermal stability. The aromatics in a Grp I break down quickly and the oil losses it lubricity causing more wear. Thinner oils also generally show somewhat more wear. So using a Grp I thinner oil is going to be like a double whammy as far as wear is concerned. One can compensate this somewhat by using higher weight oils that don�t show as much wear and hold out better. If you �re using a Grp I oil, you need every edge you can get in better protection. Fuel economy and the relatively very small benefits of thinner oil (few %) are of a distant secondary concern. There also is the issue that in very warm or �tropical� climates like Indonesia and many parts of the world, lighter weight oils probably won�t make as much difference in fuel mileage as in cooler climates. And, if you�re already using much smaller more fuel efficient engines to begin with (rest of world outside US) then a few % gas mileage really doesn�t really hurt that much. Engine protection becomes a more important parameter with Grp I based oils.

 

The problem is also compounded by the fact that Grp I oils don�t flow at cold temperatures as well as Grp II�s, so to make a 5w-20/30, you have to use thinner basestocks with I�s than if you blended with Grp II�s -- making things even worse.

 

Were seeing OCI�s of 10,000 miles in a lot of vehicle�s these days, and half that -- 5K for severe service. I think a 5w-20 blended from Grp I oil would be severely stretched to make 5K or much over that. With a Grp II -- no problem. I like this quote that pretty well sums up the performance gap between Grp I/II�s �

 

quote:

 

chevron.pdf

 

The inherent oxidation stability advantage that Group II stocks have for passing these tests is apparent in today�s engine oils. For example, Cummins and Chevron found that some commercially available engine oils consistently passed the MRV TP-1 after a 400-hour double-length Cummins M-11 test while others failed1 Subsequent analysis showed that the oils that passed were formulated with Group II. The oils that failed were formulated with Group I. A more recent study showed that Group I formulated oils stayed in grade only about a third as long as Group II (125 hours for Group I vs 400 hours for Group II) in heavy-duty engine oils formulated with the same non-optimized general offering package.

 

Grp II basestocks, because they cost the same as Grp I�s, change the equation. Why not get the benefits of a thinner oil if it protects just as well or better and costs no more. I�d take a Grp II based 5w-30 (or even 5w-20) over any Grp I based oil -- by a country mile."

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/674209/re-5w-20-people-explain-this-please#Post674209

 

Though, when I look at page 5 and 6 in the pdf below, it looks like things may not have changed as much as I thought? I'm not sure.

https://www.infineuminsight.com/media/1776/rd-b-stocks-inf-t18-june-18.pdf