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Old 05-24-2012, 11:51 PM   #11
Scooby Specialist
Member#: 220971
Join Date: Aug 2009
Chapter/Region: South East
Location: West, NC
2002 WRX 223K Mi.


Originally Posted by 79letour View Post
The dealer and soa both agreed that an oil consumption test was in order. I drop the car off saturday for a new seatback, rear hatch latch adjustment, and the oil consumption test. They said it consisted of draining the oil and measuring how much is in there, then filling it precisely with the amount the factory calls for, me driving the car for X miles and then drainiong it and seeing how much less oil there is than 5.3 quarts. At least that's what soa said.
The consumption test doesn't make much sense the way it was explained to you. Drain-back cannot be calculated that way, or at least not that accurately.

The way I do consumption tests:
1.Fill to approx 1/2 quart short of spec (Start&Run for 15 sec or so)
2.Verify Oil level in "safe" zone.
3.Test drive to operating temp.
4.Park on a known level spot - in the shop on a flat bay, NOT on a lift.
5.Time: 10min of drain back, dipstick out.
6.Check level, top off to exactly full dot.
7.Subaru spec is 1qt every 1200 miles, return to customer, have them return in nearest to 1200 miles.
8. Verify operating temp, park in same flat bay, wait 10min, dipstick out, verify oil level, note loss, if any. One Qt. to add/low dot, if not below within acceptable limits.

This way the oil viscosity is at the same temp, ambient temp does not affect it. The time is precise to allow the same amount of oil to flow back into the pan.

Also note: JAMMING the oil dipstick back in will give poor results, I've seen people check their oil like they're throwing a Javelin. Those O-rings seal so shoving it in quickly causes the oil to wave at the end of the dipstick tube giving inaccurate readings.

On a personal note, my wife's '12 Impreza was about 1/8" over the full dot from the factory fill doing the same as above. I account that to fluid expansion as with the old EJ motors that have a Full DOT and the Full HOT Notch.

At 1000 Miles I changed the oil and filter and precisely filled as described above hot. Cold it will read about 1/16" under the full dot. Consider however Full is Full, Over Full means if it was in a sealed container it wouldn't fit. It has to go somewhere, usually burnt off in the PCV or adding drag on the crankshaft diminishing mileage. I prefer to be as close as I can get to full but as long as it stays in the operating "Safe" zone. Its operating normally.

Another issue I've seen is the incorrect oil being used, this engine requires 0w20syn, the wrong weight will cause issues of oil not getting back to the pan fast enough. If you're that skeptical of your dealers work, I would ask to see the empty 0w20 bottles, I highly doubt they have 0w20 Synthetic in bulk tanks yet.

Here's the copy paste from the SM:

Engine Oil
If the engine oil is spilt over exhaust pipe or the under cover, wipe it off with cloth to avoid emitting
smoke or causing a fire.
1) Park the vehicle on a level surface.
2) Remove the oil level gauge and wipe away the oil.
3) Reinsert the oil level gauge all the way. Be sure that the oil level gauge is correctly inserted and properly
4) Pull out the oil level gauge again, check the both sides of the oil level gauge, and judge by using the lower
side engine oil level. If the engine oil level is below L line, check for oil leakage from engine and add oil to
bring the level up to F line.
5) Start the engine to circulate the oil in engine room.
6) After turning off the engine, wait a few minutes for the oil to return to the oil pan before checking the level.
To prevent overfilling of engine oil, do not add oil above F line when the engine is cold.
As the oil level gauge is used for daily maintenance, F line and L line is set assuming that the engine
is cold.
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