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Discussion Starter · #1 ·
Doh...I moronically added 5.9 gallons vice the correct 4.9 gallons (ive changed the oil like 6 times already...youd think that I would have it down) during this last oil change...so I definitely overfilled the oil. Are there any reprecussions to this at all? What is the oil pressure sensor used for? Does this sensor only measure low oil pressure, or will it reciprocate for high pressure as well?

A separate question...can you flush the coolant without lifting the car? Approximately where is the release cap under the car?

Thanks guys....
 

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Overfilling the engine oil can cause just as many problems as underfilling! Would you add a quart if you had only put in 3.9?

You can frothing, viscosity breakdown due to aeration, etc.

DEFINITELY drain the excess and get the right level!
 

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Also, the oil pressure can get high enough to squeeze oil out of the main seals and PCV valve.

Save yourself some grief and drain the excess oil out.
 

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yep....i'm pretty sure though that you'd notice it was overflowing if you were putting 4.9 GALLONS of oil in there ;)
 

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Able Knight said:
How do you suppose I drain some of the oil out without draining it all?
Loosen the plug until the oil starts to run out around the plug, without removing the plug all the way. Tighten it up when you have let enough out. It's messy, but it's easier than pulling it all the way out, catching the oil, and pouring it back in.
 

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Some cars will tolerate the extra oil.

For instance, BMW M50, M52, M54 engines can tolerate extra quart of oil. In fact, it's the recommended solution to the value ticking. When under extreme G's (read extreme driving), not enough oil is sent to the attenuators, and thus the values starts ticking. Adding an additional quart of oil resolves that issue.

Older cars will not tolerate additional oil, as mentioned above, you'll get frothing, crank drag, etc. Frothing is the worse, as it prevents a your from getting a constant oil pressure. Which results in engine shut down.

A boxer engine like the WRX should tolerate .5 quarts extra. Sorry, I don't know if the WRX has variable valve timing, and if it does, it should tolerate the additional oil.

I purchased a top-side oil changer from Groit's Garage, and it's wonderful for changing oil and sucking up excessive oil. I no longer have to get underneath my car for oil changes. The oil filter on my car is a canister type. :D

-LostLamb
 

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Most radiators will have a drain underneath and on the corners. You won't have to lift your car, just poke your head underneath and look for the drain plug. Unscrew it and drain the coolant into a catch bucket. Don't drain it into the street!!! It's illegal in most states.

Have fun.

LostLamb
 

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Discussion Starter · #10 ·
Ok thanks all....I plan to drain off some of the oil this evening. I figured that I would have to do so. I'll loosen the drain plug and let it run out for a bit. I hope I get a decent seal when I tighten it back up however, which is my number one concern. Ive only driven about 250 miles in this state, so I should be ok. For now, would loosening the oil cap reduce the pressure at all until I can get out in the pouring rain tonight and drain some of this oil?

Just for my own info, what is frothing and crank drag? Thanks again.
 

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Driving around with your oil cap loose is not a good idea. It's not the pressure that is detrimental, it's the excessive oil in the crank case.

Frothing, think of a latte with foamed milk. That foam milk can be your oil if you have too much oil in the crank case.

Crank drag, each time the crank rotates and hits the oil, there's excessive drag on it because of too much oil. Oil is viscous, and it will add some drag to the crank moving inside your case.

The worse is frothing which prevents your oil pump from working correctly, and starving the engine of oil. Think of it this way, would you like to suck foam milk from a straw or cold milk from a straw?

You'll get a good seal when you tighten it. Remember because you have oil on the bolt, you might want to check it after driving your car for 100miles. Make sure it's nice and tight. Don't need it loosening and then dropping out. It won't happen, but just in case.
 

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Discussion Starter · #12 ·
Thanks LostLamb...excellent responses. Will the sensor detect if the pressure does get too high...or is the proessure sensor only triggered by low pressure?
 

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A standard oil light in cars nowadays only detects low oil pressure. You would have to get a oil pressure gauge to determine whether or not your oil pressure is within normal operating specs.

-LostLamb
 

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before the wrx i had an RX-7. got lazy took it to the jiffy lube for a quick oil change. dude apparently gave me way to much oil, blew a couple of the high pressure oil hoses lose. sprayed oil all over the under carrage and nearly gave me a heart attack....

extra oil not good:( :(

i will never set foot in another jiffy lube...
 

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Discussion Starter · #15 ·
Ehh..i drained the oil until it got dark out...I doubt I drained enough (as it was trickling and i FEAR undoing the drain plug and sticking it back in after 3 seconds.). I am using full synth...I suppose all of these problems will still occur with this type of oil? I can't imagine sythetic oil, the most corrosive and vile liquid known to man, frothing up...hah. I probably got about .5 quarts out of there.
 

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Able Knight said:
Ehh..i drained the oil until it got dark out...I doubt I drained enough (as it was trickling and i FEAR undoing the drain plug and sticking it back in after 3 seconds.). I am using full synth...I suppose all of these problems will still occur with this type of oil? I can't imagine sythetic oil, the most corrosive and vile liquid known to man, frothing up...hah. I probably got about .5 quarts out of there.
Like I said, you can also drain it all, catch it in a clean pan, and pour it back in. PITA, but worth a try.

I've never had a problem with oil running out from around the plug, but the engine does need to be warm first for it to work right. Ahh... I'll never forget that familiar feeling of hot engine oil running down the entire length of my arm as I cranked that bolt out :eek:
 
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