This is not a Mobil 1 Plug

[hohieu]

Here's the data and some observations:

I've been using extened drain intervals since I puchased our 99 Forester in 2004 with 72.5k miles on the odometer. The car now has 132.5k miles. I've done all the scheduled (and some unscheduled) maintenance on this car, and it still runs as it did when first purchased.

 

I've changed the oil 5 times over the course of these 60k miles.

 

Oil Change Interval (OCI)

OCI #1 = 5 months/11,292 miles

OCI #2 = 10 months/10,667 miles

OCI #3 = 10 months/13,026 miles

OCI #4 = 12 months/12,974 miles

OCI #5 = 11 months/11,900 miles

 

The first two OCIs used Mobil 1 (M1) 5W/30 exclusively.

 

I had about 15 qts. of M1 15W/50 that I had purchased for my motorcycle and needed to use up so I filled the engine with a 50/50 mix of M1 5W/30 and M1 15W/50 for OCIs #3 through #5.

 

For topping off during the last three OCIs, I had Pennzoil Platinum 5W/30 lying around so I used it to top off during the colder months. During the warmer months, I topped off with 15W/50.

 

I've used Supertech oil filters for all but OCI #4 when I used an OEM filter.

 

I've not paid for an oil analysis to this point, but I can say that oil consumption has remained steady at a rate of .45 qt./3,000 miles. Fuel consumption has also remained relatively stable with no noticeable difference between straight 5W/30 and the 50/50 mix.

 

I'll pay for an oil analysis at around 200k in order to decide whether it's worth it to perform major serivce items (e.g., clutch, struts, timing belt).

 

At the next oil change, I'll have a chance to visually inspect the top end when I adjust the valves, though I don't anticipate finding any unusual sludge or deposits.

 

What I'd be curious to see is a similar set of data using conventional or synthetic blend motor oil in the same vehicle under the same conditions. I just wonder if running synthetic makes much of a difference in a normally aspirated Subie.

 

This link has been mentioned on the board before, and it's worth a look:

http://neptune.spacebears.com/cars/stories/oil-life.html

 

Edited for typos

[Quidam]

Hi,

 

The only thing I would be doing different is using a superior oil filter. And stick with one brand. Interesting test. Thanks.

 

Doug

 

Edit: One more thing, I change just the oil filter about half way and top up the oil. Not all the time, just certain engines. Once a year oil and filter in the spring is optimal for me. There are conditions where I have left Mobile 1 in the crankcase for two years, with the regular top offs as needed.

[hohieu]

Thanks for the input. I usually change my oil in the Fall because the oil thickens over time. I figure it's better to have fresh (thinner) oil during the winter months.

 

From what I've read, it takes quite a bit to plug up an oil filter causing the bypass valve to open, and my car consumes some oil so I get to top off with about 2 qts./OCI. This is why I opted not to replace the oil filter midway through each OCI.

 

I agree that I should probably stick with one brand of oil in order to avoid incompatible chemistry of additives, but I just needed to use up the Pennzoil I had on the shelf.

 

I've also left M1 15W/50 in my motorcycle, which I've had little opportunity to ride in recent years, for a couple of years.

 

I would be willing to run these longer intervals using virtually any synthetic motor oil on the market today.

[2X2KOB]

I am on a similar oil change schedule with the 2000 OBW EJ252. I have taken the oil filters apart after running them for 10K plus on Mobil 1, and observed very little crud buildup inside the filters. Maybe the stuff that the filter is catching is too small to see, but they sure looked pretty clean to me. I did this as a way to help me decide if I should change filter only at 5000 miles. Based on what I saw, I decided not to do that, and just run the filters for the full 10K, or 11 or 12K, whenever I get around to it. This is normally 3 to 4 months as I do drive a lot, I have one of those unwise commutes...

[hohieu]

At the next oil change, I'll have a chance to visually inspect the top end when I adjust the valves, though I don't anticipate finding any unusual sludge or deposits.

 

At 136.5K miles, I just adjusted the valves and replaced:

 

- PCV valve (OEM)

- valve cover gasket, washers (Felpro kit) & spark plugs well seals (OEM)

- spark plugs (Bosch coppers) & OEM wireset

- Air filter (Purolator PureOne)

 

The car was running just fine, but I decided to go ahead perform all the maintenance because all 4 spark plug well seals were leaking oil. The gaps on the old NGK plugs were still well within spec. and could have gone another 30K miles, and the PCV valve was clean as a whistle after over 60K miles of service. The valve heads were also clean as could be. I'd post some pictures, but the ones I took are too big, even after I resize them.

 

I have just a couple of observations on the valve adjustment, which was not unlike other screw adjuster types on which I've worked:

 

- It's always hard to find TDC using the alignment arrow on the cam sprocket so I stuck a ratchet extension into the spark plug holes and watched as I turned the crankshaft.

 

- Intake valves tend to loosen up over time, while exhaust valves tend to tighten up.

[nipper]

Just an FYI, oil change intervals wont rear thier ugly head till you get around 180,000 miles. Thats about where rod knock shows up from poor oil change habits, if its going to show up at all.

 

 

personally your intervals are a bit long for me, but as i say, its your wallet. i hope you have been chainging your PCV va;ve regularly to help keep down the chance of sludge building up, and that there are no short trips in there, another source of engine sludge.

 

nipper

[aircraft engineer]

most people don't understand that oil never "wears out" - it just "gets dirty". True, some of the viscosity modifiers change a bit during "use", but the lubricity remains

 

Particulate contamination and water condensation are the 2 biggest enemies of oil/engine life - the water because it can cause strange things in an emulsion due to acid formation and particulates because of "abrasive wear"

 

Generally, 5000 is a good interval for a well sealed engine with filters every 2500 or so (with oil costing a lot more than filters now - it's not that you can extend the SYNTHETIC oil usage interval - you only sort of can. Do an oil analysis every second change or so and a compression test at the same time and see trends over time) Too bad you don't have a "control" vehicle to use for comparison.

 

I know my sister changed oil every 3000 like clockwork and that 3.5 Chev V6 was still going strong at 350,000 when the dump truck pulled in front of her. (The Vortec engine is not known for especially long life)

[hohieu]

most people don't understand that oil never "wears out" - it just "gets dirty". True, some of the viscosity modifiers change a bit during "use", but the lubricity remains

Yes, and a little acid base chemistry with comubustion byproducts and fuel running down cylinder walls. These buffers do wear out as well.

Particulate contamination and water condensation are the 2 biggest enemies of oil/engine life - the water because it can cause strange things in an emulsion due to acid formation and particulates because of "abrasive wear"

Much has changed over the past few decades in oil and engine technology along with everything else on the planet. What hasn't changed' date=' however, is that most engine wear occurs duing cold startups. What's interesting about the link in my original post is that although they report a continual climb in absolute engine wear, rates of engine wear were highest during the first 3K miles of an oil's service life. The initial wear makes sense after an oil change as the oil system is completely drained. The loss in pressure when the oil is drained from the pan causes all the oil passages and channels to drain down as well, similar to what happens when a brake bleeder tube is removed from used fluid in the collection container. It takes a bit of time for the system to repressurize after an oil change.

Generally' date=' 5000 is a good interval for a well sealed engine with filters every 2500 or so (with oil costing a lot more than filters now - it's not that you can extend the SYNTHETIC oil usage interval - you only sort of can. Do an oil analysis every second change or so and a compression test at the same time and see trends over time)[/quote']

I have no vacuum leaks and aiir filtration is good on this car: for some reason, there are two air filters, one above the throttle body and another along the rignt fender. I have no test numbers to show, only that oil consumption has not increased since I've owned the car, and the old PCV valve was spotless after 60K miles of service. I haven't hooked up the pressure gauge, but I'm thinking my rings are still sealing pretty well.

I can see how a new oil filter would flow better, but it doesn't make sense that it would filter better unless the old one were completely plugged up and activating the bypass valve. I can, however, see how the make-up oil needed after a filter change would dilute the particulates in suspension and bolster acid neutralizing compounds.

Too bad you don't have a "control" vehicle to use for comparison.

Without that, this is all rather anecdotal, especially at this early point. It would be great to have a long term test in which a "control" vehicle followed me everywhere I went -- this may be a good case for cloning...

[OB99W]

[...]The loss in pressure when the oil is drained from the pain causes all the oil passages and channels to drain down as well, similar to what happens when a brake bleeder tube is removed from used fluid inthe collection container. It takes a bit of time for the system to repressurize after an oil change.[...]

Assuming the oil filter is appropriately oriented, it helps to nearly fill a new one before mounting it in order to minimize the time the engine is running "dry" after a change.

[aircraft engineer]

For the system to pressurize, yes - but another thing that most people don't realize is that the oil film remains in the bearings so no bearing damage is done to the engine during start unless there is an extremely high load during the start cycle. Similarly, cylinder walls in sliding the rings will scrape off some of the oil but the oil ring itself traps enough to take up the slack during starts.

 

Now if you want to talk about "long life between oil changes" - try a "turbine" (jet engine) - most of them are on oil analysis and only get changed at "C" check (a lot longer than 600 hours) - just keep checking it (uses very little), topping up, and running it - no combustion products in the oil stream whatever. it only rotates, no "slide action"

 

BTW - another way to fill the oil filter before start is to pull the coil plug and crank the engine. Too bad it won't work on a Sub unless you pull the coil pack wire

[McDave]

BTW - another way to fill the oil filter before start is to pull the coil plug and crank the engine. Too bad it won't work on a Sub unless you pull the coil pack wire

That was the actual procedure in the owners manual of my '81 Turbo Formula Firebird to help extend turbo life. Back in the day you could even buy a pre-oiler that would do the job for you at every startup and continue after shutdown to flush hot oil out of the turbo. It's a shame something like that never became standard equipment.

[CaptEditor]

From what I've read, it takes quite a bit to plug up an oil filter causing the bypass valve to open

 

If you live in an environment where it gets very cold the bypass valve can be very important. I had my oil pressure on my 85 VW max out my pressure gauge on a cold morning when I had a cheapo oil filter on it. Granted, it did have thicker oil in it than the subarus should have, but I still like the security. I always by the OEM filters/OEm equivilent.

 

 

-Kevin

[bratman2]

I did something similar with my middle daughter's 93 Legacy. Changed w/ M1 10w30 every 10k. Car was driven mainly in the country so once started it might go 20-30 miles before being cut off. She hit a bear with it and it would have cost more than it was worth to fix the cosmetic damage so my wife insisted I sell it off. Bought with 114k, first change to M1 @ 115k with another @120k. After that it was every 10k with a pint added every 3k to top off for usage. Saw no need to change filter myself unless changing oil. Sold car w/ 193k to a coworker to drive back and forth to work. Belt broke and car overheated w/ 218k but that overheating ended it's useful life. Now if we lived in the city I wouldn't have consider these intervals. According to the last owner it ran fine to the end and he had continued with the 10k changes.

[frag]

 

BTW - another way to fill the oil filter before start is to pull the coil plug and crank the engine. Too bad it won't work on a Sub unless you pull the coil pack wire

 

I fill the filter by hand when doing an oil change, but I could use your method easily. My antitheft system cuts out ignition and fuel delivery. So if I dont desactivate it, I can turn the engine over as long as I want without the engine starting. Is'nt that also possible with most other kiinds of antitheft systems?

[hohieu]

Assuming the oil filter is appropriately oriented, it helps to nearly fill a new one before mounting it in order to minimize the time the engine is running "dry" after a change.

Yes, thanks for the reminder OB99W. It's the first thing I do when changing the oil. I can usually fill it up at least a couple of times. Even on my other car, on which the filter is not ideally mounted, I fill it up once to let the oil soak into the filter media before installing it.

 

I had my oil pressure on my 85 VW max out my pressure gauge on a cold morning when I had a cheapo oil filter on it. Granted, it did have thicker oil in it than the subarus should have, but I still like the security. I always buy the OEM filters/OEm equivilent.

I wish Subarus had oil pressure gauges. I've never had any issues with the Supertech filters, which I think are decent filters and certainly better than Fram filters. After I ran out of the Supertechs, I went with the Purolator Premium Plus filters, which were identical to the older OEM Subaru filters. But with all the summer oil & filter deals, I caved and picked up a bunch of Mobil 1 & PureOne filters.

[aircraft engineer]

Out here, Schucks had a special on Bosch filters for $3 each

 

So I got a few. I'll use up the Frams I have, though.

[hohieu]

Yes, I've read about the Fram horror stories but feel that many of these tales are a bit over-alarmist. If you already have them, use them, but there are better filters out there for the same or less money -- purolator premium plus to name one.

 

 

This is the best forum I've seen for technical information. I'm on several others, all different makes both American and Japanese. I have just a couple of questions:

 

1) Why are Subaru owners such gearheads?

 

And I want to confirm an intutition that I've not seen explicitly stated, perhaps because it's so darn obvious:

 

2) Are horizontally opposed engines more durable because there's always some oil in the heads even after the engine is shut down?

[2X2KOB]

There are several quality levels (and price levels) of Fram oil filters. Generally I find myself at the wal-mart because they have the cheapest Mobil-1, and they ususally have a couple different Fram filters to choose from. The higher end ones seem to be pretty good. Last time I got Mobil-1 it was $16.97 for a 5 quart jug, on sale. I can handle that.