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2001 H6-3.0 O.B. LL Bean
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Discussion Starter · #1 ·
My 2001 H6-3.0 Outback makes an occasional buzzing sound for a second when I first start it up. Today I changed oil and filter and it made this sound for longer and a bit louder so I shut it down. Restarted it and everything was alright. Was that a dry engine start that I heard? I suspect it had something to do with the dry filter until it filled maybe? You can't pre-fill a sideways filter anyways.

Rick
 

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1995 2.2 Auto Legacy Sedan
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I fill the dry filter 1/3 - halfway and slowly turn it around in my hand and coat the inside and let the filter absorb most of the oil and then install it. Did this today for my first oil change and it worked just fine.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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Could be the chain rattling until oil pressure builds.

After an oil change I crank it for a moment and shut the key right off 4-5 times, by then it cranks and runs with oil pressure.
 

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2001 H6-3.0 O.B. LL Bean
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Discussion Starter · #4 ·
Could be the chain rattling until oil pressure builds.

After an oil change I crank it for a moment and shut the key right off 4-5 times, by then it cranks and runs with oil pressure.
Would that be the timing chain you are suggesting? The engine starts immediately when I turn the key and the engine revs up then returns to idle. The buzz is right where it revs and then totally goes away. It just buzzed longer than usual and spooked me. I suppose it could be the chain alright.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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If it sounds like a fast rattling probably the chain, if it's knock-knock-knock it's a dry rod bearing...
 

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2002 Outback Station Wagon & 2017 Volt
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if it's knock-knock-knock it's a dry rod bearing...
My OB is knocking when cold on start up, is there anything I can do? I does go away eventually. Put in M1 this summer when I got it and have only put on maybe 2k miles since then. Thanks
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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The next time you feel it may make the noise, open the hood and try to determine generally where the noise comes from.
 

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2002 Outback Station Wagon & 2017 Volt
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Its definately and engine knock. I have a heated garage so in the morning its quiet, but when I go home from work it knocks pretty loud until it warms up a little. I'll try to get a better idea where its coming from toinght when I go home.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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sry, I got confused in this thread.

Bmike, Occasionally, a weak TB tensioner will let the belt flop around and it can sound like a knock or piston slap, but it does seem you have a real mechanical problem. Might be piston slap which is annoying but not terribly serious. Have you tried different oil?
 

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Knocks that knock when cold and go away are usually piston slap.

Knocks that don't go away or get worse as the oil warms are rod knocks.

(generally speaking)
 

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06 Outback 2.5i, 06 BMW 325xi wagon, 02 2.5rs, 82 CB750, Polaris XC SP 500, and a single speed bike.
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After an oil change I crank it for a moment and shut the key right off 4-5 times, by then it cranks and runs with oil pressure.
You can floor the gas pedal and crank the motor to build oil pressure too -- the gas pedal floored turns off the fuel injectors. I do this with every oil change on my 2.5. Fill the oil filter, screw it on, fill the motor, and then crank the motor 2 or 3 times for 10 seconds each to prime the system a decent amount.
 

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You can floor the gas pedal and crank the motor to build oil pressure too -- the gas pedal floored turns off the fuel injectors. I do this with every oil change on my 2.5. Fill the oil filter, screw it on, fill the motor, and then crank the motor 2 or 3 times for 10 seconds each to prime the system a decent amount.
I know some cars were programmed to cut the injectors while cranking WFO (to help clear a flooded engine), didn't know subaru did that. Cool beans. I'll try it tonight (with a warm engine).
 

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2002 Outback Station Wagon & 2017 Volt
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Of course it didn't seem as loud today but I tried to record, please ignor the video just trying to get audio:

 

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You can floor the gas pedal and crank the motor to build oil pressure too -- the gas pedal floored turns off the fuel injectors. I do this with every oil change on my 2.5. Fill the oil filter, screw it on, fill the motor, and then crank the motor 2 or 3 times for 10 seconds each to prime the system a decent amount.
The 2003 H6 apparently does not have this feature- maybe this is on throttle-by-wire systems only?

Even with the injectors on it does effectively clear a flooded engine.
 

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06 Outback 2.5i, 06 BMW 325xi wagon, 02 2.5rs, 82 CB750, Polaris XC SP 500, and a single speed bike.
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The 2003 H6 apparently does not have this feature- maybe this is on throttle-by-wire systems only?

Even with the injectors on it does effectively clear a flooded engine.
Interesting. Mine isn't throttle-by-wire; I have a physical throttle cable from the pedal to the throttle body. But I have the same year H4; maybe it's a difference between motors... but that seems unusual.

Stupid question, but was it all the way to the floor? Any chance there's a floor mat preventing full throttle? It'd have to be a heck of a mat though... hmm.
 

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Interesting. Mine isn't throttle-by-wire; I have a physical throttle cable from the pedal to the throttle body. But I have the same year H4; maybe it's a difference between motors... but that seems unusual.

Stupid question, but was it all the way to the floor? Any chance there's a floor mat preventing full throttle? It'd have to be a heck of a mat though... hmm.
It may be a curled up weather tech. :)

I have never noticed a long start period that was intentionally initiated by the ECM. What it is most likely doing is taking longer to start due to the amount of available air, lack of good vacuum and low injector cycle that is allowing it. It doesn't get the proper air/fuel mix with WOT starts so it won't really create combustion to start it.

In a "flooded" engine, the WOT allows for more air to mix with the already high concentrate of fuel and with the engine rotation pumping the mix in/out, thinning the fuel portion, it eventually starts.
 

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No floor mat in the way, was fully floored.

I know the feature does exist on some cars out there...
 

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06 Outback 2.5i, 06 BMW 325xi wagon, 02 2.5rs, 82 CB750, Polaris XC SP 500, and a single speed bike.
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Now I'm confused why mine behaves this way.
 
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