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Guest Message by DevFuse
 

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I learned something very interesting...


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12 replies to this topic

#1 bgambino

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Posted 16 March 2011 - 09:10 PM

So I bought this 98 OB wagon 2.5 automatic
Now...when it starts,,,you would always here that sound...like when you just changed the oil and the pressure needed to build up? Not sure if it is the main bearings or what...but its due to the lack of built up oil pressure

But this car did it always ...unless it was still warm
In fact, on its maiden run,,,i noticed that at idle in drive, the oil light would flicker...i said oh crap! I bought it for a song so i expected anything

I changed the oil to 20/50 and no light

well...a few weeks later, theres a heavy oil leak from behind the t belt cover
ends up one of the cam seals pushed out some and was leaking
so i do a complete t belt/pulleys/wp/seals...and here's the thing
I pulled the oil pump off to replace o-ring and make sure screws are tight behind the oil pump
Well...a few were a bit loose and one was backed out several turns

so i blue loctite them all in
I never understood what this plate was all about and the screws...still dont,,and dont really care
But guess what? The oil pressure when the car was off must have been drainning out becasue of this,,,because now...absolutely no knocking sound at cold start up!!!
I'd ask if this is the reason but it has to be...I did nothing else

Needless to say I was quite relieved...and i learned something new

#2 Fuzpile

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Posted 17 March 2011 - 01:49 AM

Thanks for your informative post. Fixing those seals And the pump seal you gained an engine.:)

#3 ShawnW

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Posted 17 March 2011 - 01:55 AM

Yep, seen that quite a few times, unfortunately usually with the opposite results. Good save!

#4 unibrook

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Posted 17 March 2011 - 03:47 PM

That is interesting. Especially since my 2001 Forester with 106k is suddenly using a quart of oil every 2 months....and my timing belt is due to be changed now anyway. I will definitely be checking out that oil pump and the plate and bolts while I am in there! Thanks for the post!

#5 1-3-2-4

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Posted 17 March 2011 - 05:55 PM

is this an issue on the MY98+ cars? when I did my oil seal I never bothered to pull the pump and I never had any issues with it with the 36K I put on the car.

#6 davebugs

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Posted 17 March 2011 - 05:58 PM

If you search here, or ask here about "resealing" a 2.5 folks will tell you to pull the oil pump and chack those screws. Most of us find one or two loose. Most Loctite them - I just usually tighten them.

BTW this also leads to the discussion usually of whether to install the crank seal into the oil pump then put it over the crank. Or to install the oil pump on the crank then install the crank seal.

#7 NoahDL88

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Posted 17 March 2011 - 07:45 PM

20-w50 is also not the best choice, most of your wear is on startup, and trying to pump that super thick oil is just making it worse, If you've fixed your leaks go back to 10-w30.

#8 94Loyale

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Posted 17 March 2011 - 08:56 PM

1324, this is an issue on all EJ's really, since they all have the same oil pump setup.

#9 bgambino

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Posted 18 March 2011 - 08:47 AM

[quote name='davebugs']
BTW this also leads to the discussion usually of whether to install the crank seal into the oil pump then put it over the crank. Or to install the oil pump on the crank then install the crank seal.

Once I thought...gee...this would be so much easier to put the crank seal into the oil pump while i had it on the bench...so i did
Come to find out...for some reason I had a heck of a time getting it back in place correctly...the circular spring (not sure what it is called) inside the seal kept coming out when i would try to put the pump over the crank shaft....you wouldnt think it should...but it did
I dont do it that way any longer

#10 Fairtax4me

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Posted 18 March 2011 - 12:16 PM

A neat video for how an eccentric gear oil pump works. http://www.motoetc.c...ntric-oil-pump/
To expand on that. This design needs to e closed in tightly on both sides in order for the pressure to build properly. The backing plate on the pump is what creates the "enclosure". So if it gets loose the oil will "bleed out" through the gap between the rotors and the backing plate.

I will definitely be checking out that oil pump and the plate and bolts while I am in there! Thanks for the post!

The "plate" is on the inside, and will not cause oil to leak externally. Oil being pushed out from behind the plate goes back into the crankcase.

is this an issue on the MY98+ cars? when I did my oil seal I never bothered to pull the pump and I never had any issues with it with the 36K I put on the car.

This is a potential issue on every EJ series engine. The screws on my pump were tight. But the expansion rates of the two different metals (aluminum and steel) that the pump is composed of, mixed with engine vibration, can cause the screws to loosen and back out.

#11 unibrook

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Posted 18 March 2011 - 12:25 PM

Ok, good to know that isn't the source of my oil loss. Thx for the clarification.
Good post.

#12 1-3-2-4

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Posted 18 March 2011 - 05:06 PM

thats a nice site I've always wondered how the oil was pumped.. but I have a question.. if the oil all drains back to the pan how can the motor crank so slow with thick oil? Does the oil move that quick up the pickup tube?

#13 Fairtax4me

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Posted 18 March 2011 - 05:12 PM

Typically it doesn't drain back. The pump will in a sense hydro-lock with the engine off, and only a small amount if any will flow back into the pan. This assumes the Anti drain back valve in the filter is working correctly.
But these are a very efficient design and do move quite a bit of volume.




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