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Discussion Starter #1
Hello all,

Here FYI are the results from using Mobil 1 5W-40 synthetic oil in my USMY 02 WRX. The car has 35K miles on it, and the oil was left in use for 5,800 miles, since I'm in no mood to be changing oil every 3,000 miles in the 21st century - no reason for that IMO, and the data proves it for this particular motor and this particular oil with my use patterns.

I am a bit anal about proper maintenance, so I wanted an decent motor oil that was API SL certified and would protect the motor as well as possible with a reasonable oil change interval - I set my mind on 5,000 miles.

Mobil 1 5W-40 is labeled "Truck and SUV" as a lame marketing ploy, but turns out it's a great oil (even with no Mo in it!). It's the bottle with the yellow cap.

Here's the data:

TBN = 3.5

(All elements below in ppm):
Al 3
Cr 1
Fe 6
Cu 6
Pb 3
Sn 1
Mo 5
Ni 0
Mn 0
Ag 0
Ti 0
K 0
B 0
Si 6
Na 5
Ca 2497
Mg 419
P 937
Zn 1092
Ba 0
Flashpoit 395F
Fuel <0.5%
Antifreeze 0%
Water 0%
Insolubles 0.3%

The explanation for each item from the laboratory:
Aluminum: Pistons, bearings, cases (heads & blocks).
Chromium: Rings, a trace element in steel.
Iron: Cylinders, rotating shafts, the valve train, and any steel part sharing the oil.
Copper: Brass or bronze parts, copper bushings, bearings, oil coolers, also an additive in some gasoline engine oils.
Lead: Bearings.
Tin: Bearings, bronze parts, piston coatings.
Molybdenum: Anti-wear additive, some types of rings.
Nickel: Trace element in steel.
Manganese: Trace element, additive in gasoline.
Silver: Trace element.
Titanium: Trace element.
Potassium: Antifreeze inhibitor, additive in some oil types.
Boron:_ Detergent/dispersant additive, antifreeze inhibitors.
Silicon: Airborne dirt, sealers, gaskets, antifreeze inhibitors.
Sodium: Antifreeze inhibitors, additive in some gasoline engine oils.
Calcium: Detergent/dispersant additive.
Magnesium: Detergent/dispersant additive.
Phosphorus: Anti-wear additive.
Zinc: Anti-wear additive.
Barium: Detergent/dispersant additive.

Water and fuel dilution are indicative of short trips and idling; antifreeze means just what it implies - antifreeze in the oil therefore a failed head gasket or other bad news.

So far, so good then it seems. Since I can go 5,800 miles on the oil, changing it every 5,000 ought to be very safe and yield good results.

I'm happy with the data.
 

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Discussion Starter #3
I used Blackstone labs. I went to BobIsTheOilGuy and from the main page followed the "oil analysis" link to order the "Terry Dyson Analysis" using the product code given. What that does is get your data interpreted by T. Dyson, so that when your results are in you can get an expert opinion.

http://www.bobistheoilguy.com/terry.html

It also gets you TBN, which would cost $10 alone anyway so it turns out to be "free." I've not gotten the interpretation yet, as Blackstone sends the data to him and me at the same time etc. Should be interesting to hear the opinion though.

For free expert opinions, you could always just post the data on BITOB and people are very helpful.
 

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SD-GR

Thanks, I always find your posts informative. I've seen other posts on BITOG for wrx showing equal or close results for even 7K miles on newer engines. I use 5w-30 mobil 1 here in the hinter land, and like you am absolutely fanatical about maintenance. I put neo-syn RHD 75-90 in front and back diffs at 3K miles. Now with 13K I feel NO difference with the tranny from when it was new, which is, it is a little tight but pretty much just right.

I just wanted to ask you why not go the 7.5K miles like the manual says with this fine engine oil? It can do it. I used to be a 3K miles guy but had an old truck that I got tired of working on and I'm sure i went about 10,000 miles and 2 years on the same mobil 1 without a hitch; now I'm going by my wrx manual: 7.5K miles or 7.5 months wcf. The mobil 1 label used to say good for up to 25,000 miles before the dumbing-of-america-jiffy-lube era. Also, aren't the mobil 1 flash points a little low? Any thoughts?
 

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Discussion Starter #5
Chris Bunch,

With this data in hand I could indeed simply go 7,500 miles on Mobil1 5W-40 quite confidently.

The main reason I'm not doing it is force of habit and convenience: 5,000 is a nice round number and I can change oil every x0,000 and x0,500 miles indefinitely, with a huge safety margin (I can "forget" to change the oil for 2,500 miles past 5,000 while maintaining my warranty and above all protecting the motor very well still).

The tested flash point has dropped vs. Mobil's claim for virgin oil, but there's no fuel or water dilution and no comments have been made that I should worry, so I'm OK with that. I suppose if it kept dropping I'd see increased use, but I changed the oil anyway.

Until I run out of space or my wife discovers the stash of used oil, I am saving a bit of drained Mobil1 5W-40 with "only" 5,000 miles of use in the WRX for my lawn mower (and I admit I'm recycling perfectly good oil every time I drop off the rest...).

I used to be so nuts about all this that I'd not use a viscosity not specifically listed in the manual, but the discussion in the "Oil Change" thread cured me of that at least, so from a psychiatric standpoint I'm probably improving (I hope).
 

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Discussion Starter #7
Although I had considered the possibility of doing a filter change and topping off the oil mid-way between 7,500 mile drain intervals (so, change oil and filter, go 3750 miles, change just the filter, top off the oil, go another 3750 and then change oil and filter again) the data show this isn't really necessary.

Since my insolubles are at 0.3% I can keep the filter for at least 6,000 miles -- and I only plan to run the oil 5,000 miles anyway.

For those reasons, I will only change the filter when I change the oil.
 

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Discussion Starter #9
I should also point out that I use either a Purolator "plain Jane" filter or the Subaru part, and I also use a stock air box with a stock Subaru filter that I change every 30,000 like the manual says.

This implies that I have a newer air filter on right now, and it is probably not filtering as well as a nicely used 10,000 mile old one will once it gets a layer of muck on it. Maybe as the air filtration improves (yes, at the cost of air flow - I admit it but my priority is longevity and motor health, not an extra 0.5 HP etc.) my insolubles in the oil will decrease.

I think the bottom line here is that if one reads and follows the manual and uses quality maintenance products (and the Subaru items are quality items -- they work reliably and perform very well!) the motor will last a long, long time. To me, this is good news!
 

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dark_rex said:
great thread.

to all the mobil 1 naysayers... stop spending money on redline, amsoil and royal purple!

:)

thanks,
dR
We switched from Amsoil to Mobil 1 in our circle track modifieds because the Amsoil was coming out burnt after two races. So far this season the Mobil 1 has been great.
 

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Discussion Starter #12
I think Amsoil xW-30 has doen well in the EJ20x motors -- I remember seeing some data on 5,000+ mile intervals that were very good too.

My main problem with the stuff is that much of it isn't API SL and all of it requires more planning to find than I am willing to do.

Any good synth oil shold give low single-digit wear metal numbers in a motor driven sanely I bet.

A good air box and air filter will keep Si levels and probably insolubles as low as possible too, which is very important if the motor is to last as long as possible.
 

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Discussion Starter #14 (Edited)
I have no need for a 5W-30, as it never gets cold enough for a 5W here anyway, but it does get quite warm and the M1 5W-30 is on the thin side for a 30-weight.

I saw more consumption with straight 10W-30 than I liked, though it was still perfectly normal and quite low. I ended up adding a little 15W-50 M1 with the 10W-30 to decrease the consumption, but I didn't like that solution either.

The M1 5W-40 was initially rumoured to be the same oil as Mobil's best oil, Devlac 1 (their diesel/fleet/gas SL oil engineered for high-boost high-soot high-mileage high-money high-everything use in anything from a big rig diesel to a gas motor car). Delvac 1 is a bit hard to find (like Amsoil or worse even) and expensive. However the M1 5W40 is widespread and less expensive, and if not identical it is certainly similar (note in my data the lack of moly; other Mobil1 formulations and other oils like Castrol GTX contain moly in their additive package, however, Delvac 1 5W-40 and Mobil 1 5W-40 characteristically do not, for example).

I have no doubt M1 5W-30 or 10W-30 will work very well in my motor. However for the reasons above, and for the fact that the 5W-40 is as good at low temps as the 5W-30 while exceeding the performance specs of the 10W-30 at high temps (it is a medium 40-weght vs. a light 30-weight), I decided to run with it.

I could have selected a dozen other oils and probably gotten excellent results as well (other Mobil1 formulations, Motul, Fuchs, Selenia, Redline, Amsoil, Royal Purple, Chevron, Pennzoil, Castrol, BP, endless others). There are more options than we can cover in a dozen different threads on this board out there for anyone reading. I happened to set a few criteria, pick an oil based on these, and run with it, and the testing is showing I'm doing well. Yet I could have chosen *so* many other oils too. YMMV as they say.

In any case I posted the data as I think they show that members with similar driving conditions to mine can expect very good protection with this particular oil.
 

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I have a jug of M1 5W-30 sitting in my closet and I'm still up in the air as to whether it's too hot here for it. I'm sure the oil would hold up OK, but I think that the M1 5W-40 may provide somewhat better high-temp/high-boost lubrication. It won't get up much past 105 or so for the rest of this year, but that's pretty hot compared to most of the country. Choices...
 

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Discussion Starter #16
I see what you mean. AZ is pretty tough; I've only been there briefly but it was unbelievable outside!

If you look at the specs of the 5W-30 on Mobil's site, it should work in your climate despite the high heat on a normal road car. But if you are boosting high and/or boosting a lot and so on, you might want to look for something more robust.
 

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Discussion Starter #18 (Edited)
Since your car is a stg4, that might work quite well for you. I'd not extend drain intervals on a modded car without analysis to confirm it's ok though; my motor is stock.

BTW, is it just my browser's rendering or do my vowels with umlauts in my sig appear as Greek letters instead of German? I see two deltas where a's should be, and a phi where an o should be... EDIT: Bah, gave up, anglicanized the quote somewhat instead.
 

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Ah, so that's what the quotes meant. I thought the first one had something to do with flatulence. :)

I may just stick with what I bought (5W-30) for now because: 1) the "cool" season will be starting pretty soon and 2) I'm only driving ~50 miles/week these days, and usually driving conservatively at that (damn Tucson cops :p ).

Next spring I'll probably make the switch to Truck/SUV oil, hehe.

I have 5,500 miles on the car right now; I figure that's plenty to switch over to synthetic.

Next on the list is synthetic tranny/diff fluid (and getting rid of the vandalism of my car). :mad:
 
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