Turbo cars always burn a bit of oil and your IC will have a small film of oil inside it nothing to worry about. But putting in a quart every 600 miles seems like a bit much... but you say the previous owner never changed the oil and he had it for 9000 miles??? That probably would be your problem right there, that would defiently damage your engine and/or turbo with nothing changing the oil all through the breakin period or at any point for that matter.

 

he could've damaged the engine. not really from not changing the oil, but more likely from oil starvation or over-filling or simply from mixing oils that dont mix well.

if you are checking the oil levels properly, then that is not normal and you should take it to a dealership or someone knowledgeable about subaru's to take a look at it.

 

First,thanks for the reply guys!

Actually the previous owner kept on adding oil whenever he saw that it was reducing in level. So, yes he's been mixing old with new....

What I'm going to do is drain the oil fill it up with castrol magnetic (10W40) and observe.

Second, could the mods added on the car have an impact? They are as follows:
1) HKS trust exhaust
2) HKS SQV dump valve
3) HKS 8-point grounding circuit
4) HKS intake filter
Note: I have not reflashed the ECU. Would that warrent "reflashing"?

 

First,thanks for the reply guys!

Actually the previous owner kept on adding oil whenever he saw that it was reducing in level. So, yes he's been mixing old with new....

What I'm going to do is drain the oil fill it up with castrol magnetic (10W40) and observe.

Second, could the mods added on the car have an impact? They are as follows:
1) HKS trust exhaust
2) HKS SQV dump valve
3) HKS 8-point grounding circuit
4) HKS intake filter
Note: I have not reflashed the ECU. Would these mods warrent "reflashing"?

 

What continent are you on? Castrol do not include Magnetic in their range here; they sell it in the EU (though I don't use it, I use Fuchs usually) and in AU and southeast Asia etc.

Check the tip of the exhaust for black sticky "goo" or a very dark sooty film.

If the previous owner had unchecked boost creep issues that may have led to internal problems. Your use is excessive (assuming the quantity is measured correctly) and I'd recommend you get the car checked.

If your PCV system is working correctly and you can find no oil leaks externally, try a compression test and see what happens.

 

I proudly own one of the 3 2006 STIs in Saudi Arabia and by that I mean forget going to the dealership for any advice. A compression test (YES!) that's an idea. The reason I chose castrol is because it was recommended by one rally driver and a the subaru maintenance manager in europe. Yup I made a lot of expensive lond-distance calls

 

What is boost creep? I read about it, but (honsetly) I don't know what it is? :redface:

 

Boost creep is a rise in pressure due to the system's inability to expel it adequately. For example, a system is set to 0.9 bar but it is modified to handle more flow than stock -- without considering how to get rid of the waste gasses. Boost will reach the stock setting but then increase as the rpms increase, 0.92, 0.95, 0.97, 1.0 and so on. The system can't get rid of pressure quickly enough to drop boost; it just builds up.

Does your exhaust include the downpipe? If so, has any porting been done to avoid creep? (I don't know what parts your exhaust includes, but sometimes changing the exhaust components can lead to boost creep). Do you have a boost gauge in the car?