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2018 Subaru Outback 3.6R Limited
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Discussion Starter #1
2018 Outback 3.6R engine oil...conventional vs synthetic?

Time for my first oil change at 6,000 miles, and wondering whether to get conventional oil for about $35, or synthetic for about double the price. Anyone know the pros and cons? Does the car come with conventional off the lot? Can you switch back and forth? Can you mix the oils?
 

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I simply cannot abide useless people.
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I suggest your owner's manual.

It will state 5w30 API SN or newer synthetic recommended but not required.

It comes with synthetic.

Yes you can switch if you want.

Of course you can, otherwise there would be no such thing as synthetic blends.
 

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2015 Outback Limited 3.6r
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2018 Outback 3.6R engine oil...conventional vs synthetic?

Time for my first oil change at 6,000 miles, and wondering whether to get conventional oil for about $35, or synthetic for about double the price. Anyone know the pros and cons? Does the car come with conventional off the lot? Can you switch back and forth? Can you mix the oils?
The manual recommends and ships with synthetic for the 2.5i. It ships with conventional for the 3.6r and gives the viscosity, however it reccomends synthetic as an alternative.
It is written very weirdly in the manual, but yes you can add synthetic. Viscosity is labelled in the manual, don't know off the top of my head.
You can switch back and forth, but not recommended. Personally I would flush with some extra oil. You also should not mix oils, but as a guy coming from a 2.5 that would consume it, I did top it off with another brand of oil, as I don't know what was in before hand.
Your mileage may vary lol

My Professional recommendation is to follow the manual in this regard. The service intervals on the Gen 5's are pretty good, although I personally think the CVT is a wear item that should be changed at 100k.
 

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I suggest your owner's manual.

It will state 5w30 API SN or newer synthetic recommended but not required.

It comes with synthetic.

Yes you can switch if you want.

Of course you can, otherwise there would be no such thing as synthetic blends.
What he said.
 
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2018 Subaru Outback 3.6R Limited
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Discussion Starter #6
still confused!

Thank you all for your input! I'm still confused though. One person says it ships with conventional oil, another says it ships with synthetic. I get the feeling that the people in the Subaru service department don't know what's best. I've heard synthetic is better for the engine. Does it really make a difference?
:confused:
 

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2007 2.5 L Obsidian Black Outback XTL
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I have used Mobil 1 full synthetic for more than 12 years in my Mercedes. It is a Class IV/ V oil that is not made from mineral oil base-stock.

Because it is not made from mineral-oil it does not have problems with viscosity changes, unstable hydrocarbons that turn to acid and then to sludge, deposit buildup or changes in lubricity.

Oil Base Stock (about 80% of what makes up an oil);

Type I Solvent refined Mineral Oil
Type II Hydrotreated Mineral Oil
Type III Hydrocracked Mineral Oil (gas to liquid)
Type IV PolyAlphaOlefins (PAO)
Type V Esters and Alkylated Napthalines (AN)

IV and V, no waxes (that inhibit low temp operation), naturally high viscosity
no blends of hydrocarbons, low volatility, nothing to boil off
no unstable hydrocarbons that oxidize (less deposits), does not break down

The two best oils are Mobil 1 (#1) and Amsoil (#2)

Here is a good article on Type 4 oils; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jsl.3000130105

And for the chemists out there; http://utsrus.com/documents/seminary_doklady/exxon_mobil_pao.pdf
 

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moved thread to oil section.

we need another there anyway to fill in the gaps.:wink2:
 

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2018 Subaru Outback 3.6R Limited
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Discussion Starter #11
I have used Mobil 1 full synthetic for more than 12 years in my Mercedes. It is a Class IV/ V oil that is not made from mineral oil base-stock.

Because it is not made from mineral-oil it does not have problems with viscosity changes, unstable hydrocarbons that turn to acid and then to sludge, deposit buildup or changes in lubricity.

Oil Base Stock (about 80% of what makes up an oil);

Type I Solvent refined Mineral Oil
Type II Hydrotreated Mineral Oil
Type III Hydrocracked Mineral Oil (gas to liquid)
Type IV PolyAlphaOlefins (PAO)
Type V Esters and Alkylated Napthalines (AN)

IV and V, no waxes (that inhibit low temp operation), naturally high viscosity
no blends of hydrocarbons, low volatility, nothing to boil off
no unstable hydrocarbons that oxidize (less deposits), does not break down

The two best oils are Mobil 1 (#1) and Amsoil (#2)

Here is a good article on Type 4 oils; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jsl.3000130105

And for the chemists out there; http://utsrus.com/documents/seminary_doklady/exxon_mobil_pao.pdf
Thanks for the info on the oil types!
 

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2015 3.6R Limited w/ES
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There was some evidence (at least for the 2015 MY), from 1 or 2 folks claiming to have had correspondence with SOA, that the 3.6 engine is indeed filled with conventional from the factory. There was also someone claiming to have been told by SOA to run conventional for at least the first oil change or two (a dusty habit, perhaps not applicable to modern engines, although it can't hurt). I suspect those living in more severe climates, and/or with a tendency to put the engine through relatively "severe service", may stand to benefit more from the enhanced performance. Theoretically, you can extend your OCI with synthetic under some conditions (only advisable with a proper UOA, and the understanding that you will no longer be meeting warranty requirements).

Use whichever makes you feel better.
 

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2007 2.5 L Obsidian Black Outback XTL
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I could see doing a partial (less than 1 qt) drain at 3-6K and pulling a sample for analysis. Then topping off with SeaFoam, running it for 100 miles and then doing a complete drain-down, filter replacement and fill with a good synthetic.

The Seafoam will put in to suspension some of the stuff that may be accumulating from the non-synthetic oil, giving the oil system and pan a good rinse down.

Save the old oil, put it in a old oil jug and drop a high power magnet in the jug at the end of a string. Slosh it around once or twice a day for a week, then pull the magnet to see if you are getting any chips or metal flake from the break-in interval.

The first oil change and lab analysis would be your baseline. Maybe once a year during an oil change, pull another sample and send it off to the lab.

------------------------------
When I worked in the petrochemical industry we did the same thing on all of our big motors and pumps (1000-5000 HP) that ran for 18-20 hours/ day and were originally installed in 1964. An entire pump-motor set was worth about 2 million dollars and the oil analysis gave us an idea of we were having problems with oil slinger rings, ball bearings, babbited sleeve bearings, heat exchangers or water intrusion.

I was the engineer who also double-dutied as the "lab chick" so process instrumentation and long term performance monitoring were my thing.
 
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'20 Outback Onyx XT AGM/'04 Forester XT
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I have used Mobil 1 full synthetic for more than 12 years in my Mercedes. It is a Class IV/ V oil that is not made from mineral oil base-stock.

Because it is not made from mineral-oil it does not have problems with viscosity changes, unstable hydrocarbons that turn to acid and then to sludge, deposit buildup or changes in lubricity.

Oil Base Stock (about 80% of what makes up an oil);

Type ISolvent refined Mineral Oil
Type IIHydrotreated Mineral Oil
Type III Hydrocracked Mineral Oil (gas to liquid)
Type IVPolyAlphaOlefins (PAO)
Type VEsters and Alkylated Napthalines (AN)

IV and V, no waxes (that inhibit low temp operation), naturally high viscosity
no blends of hydrocarbons, low volatility, nothing to boil off
no unstable hydrocarbons that oxidize (less deposits), does not break down

The two best oils are Mobil 1 (#1) and Amsoil (#2)

Here is a good article on Type 4 oils:


Just an FYI but this information is a bit dated as XOM has been using Group III base stocks for several years now. Do a google search on Exxon Mobil Visom base oil.

These days it’s rare for an oil to be made with only one type of base stocks and XOM blends III, IV, and/or V in Mobil 1. The most important factor is the specs that an oil meets and not the base stocks.

Besides, synthetic is only a marketing term with no industry definition. At half the cost, I’d go for conventional in a heartbeat.
 

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2018 Touring 3.6R
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I suggest your owner's manual.

It will state 5w30 API SN or newer synthetic recommended but not required.

It comes with synthetic.

Yes you can switch if you want.

Of course you can, otherwise there would be no such thing as synthetic blends.
Actually, it says (and I quote):

"Your vehicle was designed to use 5W-30 conventional motor oil, however 5W-30 synthetic may be used for optimum engine performance".

Nothing in that statement would convince me it ships with synthetic oil.
 

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I simply cannot abide useless people.
I has wagons.
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They've changed it from previous years it seems. Conventional from factory now. Neat.

Rest of my statement is still correct.
 

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2018 Outback 3.6R Touring
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conventional in 3.6 factory fill

I recently contacted SoA about my 2018 3.6R and they said conventional oil is used for the factory fill. I run synthetic and switched last time I changed my oil.

Search YouTube for "Is Synthetic Motor Oil Better For Your Car?" by Engineering Explained.
 

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I have used Mobil 1 full synthetic for more than 12 years in my Mercedes. It is a Class IV/ V oil that is not made from mineral oil base-stock.

Because it is not made from mineral-oil it does not have problems with viscosity changes, unstable hydrocarbons that turn to acid and then to sludge, deposit buildup or changes in lubricity.

Oil Base Stock (about 80% of what makes up an oil);

Type I Solvent refined Mineral Oil
Type II Hydrotreated Mineral Oil
Type III Hydrocracked Mineral Oil (gas to liquid)
Type IV PolyAlphaOlefins (PAO)
Type V Esters and Alkylated Napthalines (AN)

IV and V, no waxes (that inhibit low temp operation), naturally high viscosity
no blends of hydrocarbons, low volatility, nothing to boil off
no unstable hydrocarbons that oxidize (less deposits), does not break down

The two best oils are Mobil 1 (#1) and Amsoil (#2)

Here is a good article on Type 4 oils; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jsl.3000130105

And for the chemists out there; http://utsrus.com/documents/seminary_doklady/exxon_mobil_pao.pdf
My 05 SLK350 has Mobile 1 euro spec stickers all over the place under the hood. It hasn’t run Mobile 1 since its 3rd oil change per the high performance shop it gets serviced. #1 reason being US spec Mobile 1 around 2009 went to a super cheap unstable base stock. All my cars had issues with it heavy useage literally over night. The SLK gets Rotella some fancy stuff. My Ford, Toyota and Subaru get Chevron oil changed at home. SLK only gets about 3000 a yr on a heavy yr. So the local german leo services it. My other cars I have too many plus a **** boat I service or ID go broke.
 

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Discussion Starter #19
Got the oil changed...and the winner is........

Thank you all for the input on conventional vs synthetic oil! We ended up getting conventional oil today. Might switch to synthetic sometime in the future.

I was really glad that they did the oil change and tire rotation for free...plus they washed my car...so it's all pretty and shiny white again. Why did they do it for free? Because I went in the morning, got checked in, got my coffee latte, and went outside to the sales lot...then they called me on my cel to say that they didn't have any filters...so could I come back later? Sure! Then he said he wouldn't charge me, because of the inconvenience. That was nice!
 

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I suppose if you go somewhere to have your oil changed conventional vs. synthetic could be a $$ question
but if you change yourself, I haven't paid more than $20 for a jug of Mobil 1, in fact the last two were $15, it is a no brainer. Somebody always has it on sale and often there is a rebate.
I've paid as little as $1.75 a quart for it.
 
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