I only have 25K miles on my 04 WRX sedan and ever since I
bought the car at 17K miles the car has had this oil consumption
problem where the car would use or burn two quarts of oil in about
a two to three week period.I was useing Mobil 1 5W30 and now I
am useing Castol syntec blend 10W30.In about two weeks it uses
one quart now why is my car useing oil guys? I don't have any mods?
Thanks.

 

Question: did u buy it from the dealer?
Answer: Bring it to a shop and have them inspect your engine. Its probably head gasget or previous owner maxing out the turbo thus making it burn hot oil away.

 

I have similar problem. The oil goes from "H' to "L" on the oil dip after about 2k miles. My friend told me that wrx should use at least 10-30 or even 20-50. I'll try that in the next oil change and see whether this problem can be resolved. The expected behavior would be a little bit less MPG.

 

I will be taking my car to the Subaru Dealership to see if they can
find a problem with my engine.My car is under warranty anyway.
I talked to a Subaru tech before and he told me to use 10W30 oil.
The tech said 5W30 was too thin of a oil to use.
If you use a heavier weight oil than your MPG will go down some yes.
I just don't think it is normal to use as much oil as my 04 WRX does
it's a shame.The Subaru tech did say if their is something really wrong with your
engine than we will install a brand new engine under your 100K mile
warranty you have.If that is the case I will be driving a rental car for over
a month lol.