OEM recommends 7,500 mile oil change interval.

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James614
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Re: OEM recommends 7,500 mile oil change interval.

Post by James614 » Thu Dec 13, 2012 10:26 pm

Ruckus293 wrote: manufacturers are turning towards thinner viscosity's because they are under stringent legislation to boost fuel economy by 2014. thinner oil= less friction. one issue i predict with automakers going to thinner viscosity's is the long term repercussions such as seepage through the rings. nowadays if your engine starts to get soft you can boost your viscosity and limit it to a certain extent. these new cars have such minute tolerances that they will not operate correctly without the right viscosity and sometimes not operate at all.
I've been wary of that too... would anyone here happen to know by chance, how much thinner 0W is than 5W/10W that cars from the 90s to now typically run?
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Re: OEM recommends 7,500 mile oil change interval.

Post by Ruckus293 » Thu Dec 13, 2012 10:57 pm

I've been wary of that too... would anyone here happen to know by chance, how much thinner 0W is than 5W/10W that cars from the 90s to now typically run?
the stated viscosity is still the same standard it was in the 90's and it doesnt matter whether its a synthetic or conventional; its a standard unit of measure.
pour point(degrees F):
0/20= -48
5/20= -40

Viscosity (C=degrees C):
(cSt @40C) (cSt @100C)
0/20 45 8.5
5/20 43.3 7.8

Viscosity index:
0/20= 170
5/20= 150

(notice there is some variation amongst the numbers but if looked at on a larger scale the differences are very minute)

http://www.service-pro.com/documents/Wa ... orOils.pdf

the first number is you're cold viscosity. oils have 2 viscosity's because when its cold you need a thinner oil which can still circulate effectively. as the oil warms up the additives expand to the second number which is you're operating viscosity. the first number is not a huge deal, especially if you let the car warm up and dont punch it right after start up.

think of oil in the same light as you see your man-parts. when its cold it shrivels to reduce surface area (friction) and helps attract heat. as it warms up it expands to create more surface area.
-its still all one molecule, its just whether or not its compressed to a 5(1st number) or expanded to a 20(2nd number)
-when the engines hot and running you want that friction and molecular girth to keep it from slipping by the seals.

(this isnt usually how i demonstarte it to customers but its kind of hard to explain without being in front of you)

James614
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Re: OEM recommends 7,500 mile oil change interval.

Post by James614 » Thu Dec 13, 2012 11:43 pm

A lot more than I was asking for, but answered my question, lol. It doesn't seem like there's such a huge difference between 0W-20 and 5W-20 to really cause concern to me, so long as the right stuff goes in the right engine. Lube shops will have to be especially careful... some cars like the Charger V6 will throw an oil light with too-thin a viscosity in there.
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Re: OEM recommends 7,500 mile oil change interval.

Post by Ruckus293 » Fri Dec 14, 2012 1:08 am

yea, sorry about that. i figured id lay it all out there.

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Re: OEM recommends 7,500 mile oil change interval.

Post by James614 » Fri Dec 14, 2012 1:37 am

Lot's of info is better than too little.
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05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.

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Re: OEM recommends 7,500 mile oil change interval.

Post by Legacy777 » Fri Dec 14, 2012 4:14 am

James614 wrote:It doesn't seem like there's such a huge difference between 0W-20 and 5W-20 to really cause concern to me...
I guess my take on this....and I'll let Ruckus correct me if I'm wrong is that the difference between a 0W-20 and a 5W-20 is that the base oil is different, and if you let the oil run too long the additive package will wear out and the 0W base oil being thinner may not protect as well as the base 5W oil.
Josh

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Re: OEM recommends 7,500 mile oil change interval.

Post by Ruckus293 » Fri Dec 14, 2012 5:37 am

I guess my take on this....and I'll let Ruckus correct me if I'm wrong is that the difference between a 0W-20 and a 5W-20 is that the base oil is different, and if you let the oil run too long the additive package will wear out and the 0W base oil being thinner may not protect as well as the base 5W oil.
almost josh. they both share the same base oil. a synthetic oil is a class III or IV base oil; all grades are made from the same base. conventionals on the other hand are class I or II. the producers are shipped barges of a class of base oil which they then make into all the grades.

a 5/20 and a 0/20 will last the same amount of time when compared side to side. the only difference you will see will be cold start performance and wear. once up to temp, they are an equal product (20wt).

synthetics will out run conventionals when compared side to side because synthetics have the ability to maintain their additive packages for longer periods.

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Re: OEM recommends 7,500 mile oil change interval.

Post by Legacy777 » Fri Dec 14, 2012 7:07 pm

Thanks for the clarification.

So a 0/20 & 5/20 will act the same and/or have the same viscosity when their additive packages wear out?
Josh

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Re: OEM recommends 7,500 mile oil change interval.

Post by subytech » Sat Dec 15, 2012 3:12 am

James614 wrote:If you're using whatever cheapest oil you can find, I'd agree wish you. But with a good quality oil you know doesn't turn to chocolate cake under normal use, its just throwing money down the drain. But as a tech you tend to see he worst of everything, so it makes sense you'd be more cynical of extended intervals. Let me just say that my cars are not appliances, I use oil that I know from experience doesn't tend to sludge, and I take things like how frequently the car is driven and if its been inside or outside into consideration and also typically always drive at least long enough to bring the oil up to temperature. So I won't be caught dead pouring out perfectly good oil at 3750 miles, thank you.

And most OEMs care something about their cars lasting beyond the warranty. Honda/Toyota/Subaru/Volvo all have shorter warranties than Chrysler or GM. Without a pre existing reputation for their cars lasting so long as to make the warranty period largely irrelevant, they would have had to extend their warranties to remain competitive.
I agree and disagree. I do see a lot of low mileage catastrophes but I also see a lot of well maintained cars with high mileage that just need gasket replacements and those are the cars I'm talking about. Also you are in about the 0.01% of people who take extremely good care of their car so you really have no use fallowing 90% of what I'm saying. So you, specifically, don't need to change your oil at 3750 due to your driving habits. You would fall into that other 50% I was talking about in my first post.

Unless you have a newer turbo Subaru. I only say that because I've lived through the whole botched owners manual, 05 and newer turbo fiasco. Those motors are just too high strung & not clean enough to have extended oil change periods, hence SOA's mandate that all oil changes are to be done at 3750 miles with full synthetic otherwise no warranty for 2011 and up, there is no difference in the new vs. old engine.

I also agree that OEM's care about their cars lasting after the warranty period, but having worked in a multi brand shop/dealer group, I can tell you with some confidence that as far as longevity of parts go they only look at that warranty stop date, all else is about how much the customer likes the what they can touch and feel. A lot of that has to do with marketing and politics, it still blows me away that Subaru is still selling cars in the states with their continuing head gasket problem, I mean come on that started in the mid 90's! Also with the absolute avalanche of recalls on the 2010 Outback when it came out, AND for the next year and a half? Also I've heard from friends in the industry that Honda, Yoda and before I left even Subaru were talking about a 100,000 mile warrenty. The only reason Chrysler/GM/Ford are already there is because they are trying to dig themselves out of a reliablility hole they dug trying to stamp out too many cars too fast without talking to their customers first, and Hyundai/Kia is undercutting the cheap car market that they used to have a firm grasp on.

But I digress. So yes, since you always use good oil, warm you car up to operating temp, and are mindful of your operating environment then, like I first stated, you would not fall into a severe service catagory and would be just fine going for a longer period.

Wow, now I'm ranting, damn oil change threads! lol guess its all that pent up frustration coming through after 5 years with an OEM :smt076
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Re: OEM recommends 7,500 mile oil change interval.

Post by Apex3 » Sat Dec 15, 2012 9:21 pm

Changing your oil too often can actually be harmful to your engine, it's not just the cost involved, you actually shouldn't change it every 3k(at least for normal driving). But full disclosure I'm not 100% on that, I've read it but nobody seems to be totally sure.

Your oil filter wears out faster than the oil does, at least on synthetic, the oil itself can go for quite a while without being changed.

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Re: OEM recommends 7,500 mile oil change interval.

Post by James614 » Sat Dec 15, 2012 11:19 pm

I've never heard of changing oil too often being bad. As Steven pointed out in one of his very long rants, people who religiously follow said advice often have very long-lasting, well-maintained vehicles.
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05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.

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Re: OEM recommends 7,500 mile oil change interval.

Post by subytech » Sun Dec 16, 2012 12:55 am

I've NEVER heard that changing oil too often will hurt an engine. Maybe on initial break in depending on who you talk to and for sure damaging to your wallet but thats it.
92 Legacy Turbo, 5sp MT, Early Large CC 20G heads, Ported custom clocked td04, Cobb catted DP, Injen SS 3" exhaust, Turbosmart MBC @ 10psi, Apexi 20g intake, custom FMIC, Fidanza 11lb flywheel, stock 05 WRX clutch

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Re: OEM recommends 7,500 mile oil change interval.

Post by Ruckus293 » Sun Dec 16, 2012 4:43 am

yes josh, 5/20 and 0/20 are the same oil before the additive packages. and truth be told the base oil almost never really goes bad. it can be recycled, cleaned, and brought back to a high grade class I or II base oil which can then be re-processed.

the issue i have with this is purely price; it is not a significant deduction. once the price point is where it should be i will be the first one on this forum promoting it.

it is not a good idea to change a new motors oil prematurely on break-in and can even be a bad thing. you need the oil to get into the nooks and crannies with the motor as it begins its initial wear. many engine builders will tell you that upon delivery (some builder recommend high idling non detergent oil in the system to hydrate the system without additive contamination). changing it before it is ready and "cured", for lack of a better term, can deplete the system of its hydrating properties. after that, however, feel free to change your oil every 10 miles if you want.

now there is almost no factual basis on that last statement. i have met with engine manufacturers (cummins, detroit diesel, ford, gm; as well as dave rebello, and jim thompson @ sunbelt motors) and this seems to be a general consensus. believe it or not this issue comes up quite frequently and even lead engineers have no for-sure answer.

it is still a mystery

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Re: OEM recommends 7,500 mile oil change interval.

Post by Apex3 » Sun Dec 16, 2012 6:03 am

I've definitely read that it's just in general that too often is bad, not just on new, but there's a good possibility that whoever said that was thinking of the new engine break in.

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Re: OEM recommends 7,500 mile oil change interval.

Post by allnines' » Sun Nov 13, 2016 4:45 pm

I just need to get my tranny fixed and get an oil change-its been over two years!-but, I did finally reach 210K!
Legacys are like potato chips-you can't stop at one!

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