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I use Mobil One Super Synth 10W- 30. I'm sure many of you do as well. I was wondering if those of you who use the same oil change it every 3,000 miles, or if you pass that mark by a bit...by bit I mean somewhere between 500 - 1,000 miles. Thanks in advance :)
 

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I'd say it really doesn't matter...

If you drive the car hard a lot, then change it at 3000, it's prolly good in the long run.

If you don't drive the car too hard, then you can afford to wait...

Take this for what it's worth. I change mine every 3200 er so, because I like to have fresh oil in. :p
 

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Yeah, I was figuring that if I go every 3,500 miles then I should be okay. I drive a lot...not necessarily hard...just a lot. So the 3,000 miles comes quick for me, and it's kind of a hassle to change the oil at such short time -- not distance -- intervals.
 

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I also use the same exact oil you use (Mobil 1 10-30W) and I change my oil every 3000 miles, give or take a couple of hundred extra. I really do beat the hell out of my car on a daily basis, so there is no reason why I don't give my pride and joy a new blood transfusion every 3000 miles. She deserves it.
 

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blackshadow said:
I change mine every 5000 miles. I use the exact same oil as you.
Wow...how does the oil look when you change it after so many miles?
 

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It's dark, but i wouldn't say that it's significantly darker than at 3000 miles. The only part I worry about is the filter. I believe this has been discussed before though...
 

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also to clarify, the oil "feels" clean, and i don't think it has broken down in a way that would risk damage or performance loss in any way. I definently care for my car. Mobil one synthetic really is good enough that i trust it for 5k miles. Unless someone can prove to me otherwise.
 

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Not changing at 3K mi is not a matter of "missing the mark," as there simply is no mark. None. To maintain your warranty in case of a motor failure you ought to follow Subie's interval and grade rec's, but other than that, the only way to know if it's time to change oil is to do oil analysis. The lab will let you know how the oil is holding up, and whether you've got elevated insolubles in there etc.. It's a matter of sampling 100 ml or so from the middle of a slow drain, sending it in with a check, and getting the news in the mail to find out, but I concede it's a huge hassle at times and I presonally don't like doing this. Cost is about as much as a full synth oil change.

Dark oil isn't good or bad; for every person that says "the oil is black, it must need changing" there's another that - like me - *likes* dark oil, b/c I believe that if it's dark, it's got nasties in solution, which is one reason I put it in the motor in the first place. I too use M1 10W-30, since M1 doesn't come in a 10W-40 that I'd prefer and the fantastic M1 0W-40 is not a permissible range according to our manuals in the US. M1 is on the thin side of the xW-30 range, and I don't know how well it'll hold up with typical use in my climate (southern CA USA), but I'll just have to find out.

I won't accept intervals shorter than 4K at this point, as there's no reason for a road car to use synth oil at a faster pace in the 21st century IMO. I plan to run this first lot of M1 for 3750 like the "good book" says, then increase the drain interval as I get an idea of what's going on. The first change isn't going to be meaningful data-wise, since the motor is still newer and the synth is diluted with some remnants of dealer dino juice. As I go a couple more drains, that'll no longer be an issue. We'll see...
 

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SD_GR said:
Not changing at 3K mi is not a matter of "missing the mark," as there simply is no mark. None. To maintain your warranty in case of a motor failure you ought to follow Subie's interval and grade rec's, but other than that, the only way to know if it's time to change oil is to do oil analysis. The lab will let you know how the oil is holding up, and whether you've got elevated insolubles in there etc.. It's a matter of sampling 100 ml or so from the middle of a slow drain, sending it in with a check, and getting the news in the mail to find out, but I concede it's a huge hassle at times and I presonally don't like doing this. Cost is about as much as a full synth oil change.

Dark oil isn't good or bad; for every person that says "the oil is black, it must need changing" there's another that - like me - *likes* dark oil, b/c I believe that if it's dark, it's got nasties in solution, which is one reason I put it in the motor in the first place. I too use M1 10W-30, since M1 doesn't come in a 10W-40 that I'd prefer and the fantastic M1 0W-40 is not a permissible range according to our manuals in the US. M1 is on the thin side of the xW-30 range, and I don't know how well it'll hold up with typical use in my climate (southern CA USA), but I'll just have to find out.

I won't accept intervals shorter than 4K at this point, as there's no reason for a road car to use synth oil at a faster pace in the 21st century IMO. I plan to run this first lot of M1 for 3750 like the "good book" says, then increase the drain interval as I get an idea of what's going on. The first change isn't going to be meaningful data-wise, since the motor is still newer and the synth is diluted with some remnants of dealer dino juice. As I go a couple more drains, that'll no longer be an issue. We'll see...
You know, I was reading your post, and was thinkng, "wow this dude really knows his stuff." But then I read your signature, and thought, "oh crap!"

J/K :p ;) Thanks for the info :)
 

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You're quite welcome, and thanks for noticing my .sig... Now that I think of it one question that comes to my mind is what kind of consumption people are seeing, if any, with 5W-30 or 10W-30 M1. I'm hoping the 10W stuff I'm using will keep use at a minimum, and will let you guys know if anything outrageous happens. Good thread!
SD
 

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I use very little oil. I haven't had to add oil at any point other than oil changes. Then again i only have 15k miles so the engine is in a pretty sweet spot right now.
 

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Great. I used ~300 ml in 3K miles once, but that was dino juice and probably 5W-30 since the dealer put this in. I have to wonder about M1 since it is on the thin side, but it's truly great oil so I'm hoping top-offs will be minimal with 10W-30 M1. I know LS1 folks spike it with some 15W-50 to help with their consumption, but I don't think we'll need to do this and your experience is very positive. Thanks!
SD
 

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I know this has been discussed, but do you recommend 5W-30 or 10W-30? If either, which is better for summer, and which for winter? :D

P.S.: I did my first oil change this weekend (by myself)...lol at 4900...first one was at 1700 by Lubestop;)
 

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A 5W-30 will generally provide marginally better fuel economy than a 10W-30, and certainly better cold startup protection than a 10W-30 in climates with a heavy winter. There are exceptions, where manufacturers post very close specs for their 2 oil grades. Many 5W-30s and 10W-30s from the same maker are chemically quite close, differing in the additive package and/or maybe the viscosity index improvers.

If you have a severe winter, you might want to use 5W-30 for the colder months and switch to 10W-30 for the wamer months. or just use 5W-30 year round. I don't deal with a winter worth speaking of, and I do have rather warm operating conditions in my area. 5W-30 is a broader "spread" than 10W-30, and my suspicion is that the 10W grade of the same oil - M1 in my case - will stay in grade longer and hold up better, longer than a 5W. This is at the expense of an MPG or so perhaps, but oh, well. I see no need to use a 5W in my area other than to "satisfy" CAFE standards, so I'm going 10W-30, which is still a listed grade and apropriate according to the temp charts in the manual. Your area may vary so check the chart for the grade(s) you can use.

If you do your own oil changes, keep your dated receipts so you can document them to a dealer in the future - may you never, ever need to though.
 

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Here is some great info I found on engine oil:

Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.

At the low-temperature end, oil has to be resistant to thickening so that it flows more easily to all the moving parts in your engine. Also, if the oil is too thick the engine requires more energy to turn the crankshaft, which is partly submerged in a bath of oil. Excessive thickness can make it harder to start the engine, which reduces fuel economy. A 5W oil is typically what's recommended for winter use. However, synthetic oils can be formulated to flow even more easily when cold, so they are able to pass tests that meet the 0W rating.

Once the engine is running, the oil heats up. The second number in the viscosity rating--the "40" in 10W-40, for example--tells you that the oil will stay thicker at high temperatures than one with a lower second number--the "30" in 10W-30, for example. What's really important is that you use the oil viscosity your car's owner's manual recommends.



Quoted from this link: http://popularmechanics.com/automotive/auto_technology/2002/8/motor_oil/index3.phtml
 

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I changed my oil to synthetic at about 6000mi. I went ahead and used M1 0W-40. I couldn't see any harm in using it (it is factory fill for all porches and Mercedes) although I wasn't aware that the manual did not say it was an acceptable weight. Is there any reason why we shouldn't use a 0W-40 synthetic oil in our wrx's? I have a hard time imaginig a reason why we couldn't use this oil in our cars, as long as we monitor the oil level and keep it topped off. Thanks.
 

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wrxdude said:
Is there any reason why we shouldn't use a 0W-40 synthetic oil in our wrx's? ... Thanks.
None at all. Actually, there's compelling reasons to *use* M1 0W-40. It is their flagship gasoline engine oil in the USA. It meets ACEA A3-02 and Merc's MB229.3; both are very stringent specs (whereas API SL is laughable in comparison). I can only think of a very select group of oils commonly available in the USA that meet these specs and are therefore engineered to such high standards (and M1 15W-50 is one of them).

I assume M1 0W-40 is not derived from the same basic formulation as their xW-30 series (these oils are still quite good, probably the best on the shelves in most stores right now, meeting ACEA A5).

The only reason I don't use M1 0W-40 is the warranty requirement. The book specs 5W- or 10W-30, 10W-40, 10W-50, 20W-50. Not 0W-40 and not 15W-50, so no Mobil1 ACEA A3 oils! Sad, silly, but true.

SD
 
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