Subaru of America does not recommend the use of any engine oil additives in any Subaru engine crankcase. Subaru engines are designed to be lubricated with normal petroleum or synthetic-based engine oils in the viscosity and grade indicated in the Owner’s Manual for each specific engine and usage condition. Subaru has not tested the effectiveness or compatibility of any engine oil additives.
However, the use of such oil additives does not void warranty coverage. Usage of any additive is at the owner’s discretion. Since Subaru has not tested the compatibility or effectiveness of any such additives, should an engine failure occur that is determined to be caused by the incompatibility or performance of such an additive, the vehicle owner would be be referred to the additive manufacturer to request reimbursement of the cost of the repair.
If you are using oil additives to try to save a leaking headgasket it’s better to just suck it up and just either install new headgaskets yourself or have the work done by a trusted mechanic.
Either use Subaru’s OEM synthetic motor oil or use Rotella T6 motor oil. If your Subaru is still under warranty by Subaru it’s best to get your oil changed by a Subaru dealership and avoid introducing oil additives into your boxer engine. Even if it’s Subaru’s official stance that they won’t void warranties if oil additives are involved it doesn’t mean that they won’t if there is more evidence of engine “tampering”. Avoid anything that could potentially cause a dealership to refuse service to your car in the future.
Otherwise you might have a expensive repair bill if your Subaru boxer engine spins a bearing or has a ringland failure. Of course adding aftermarket parts like an exhaust or intake along with a tune will greatly increase the justification of a Subaru dealership to void a warranty more than adding oil additives.
Not adding oil additives can be another step in avoiding a void warranty from Subaru of America. On a final note remember that Subaru can scan your ECU for previous tunes even if you went back to a stock tune and will void a warranty for that.
If you’ve never changed oil on a 04-07 WRX STi this guide will take your step by step through the oil change process. This guide should be applicable to most turbocharged Subaru cars throughout the years. Check at the end of the post for part numbers, oil, filters and tools needed to complete an oil change.
1.) Get you car on a hard, even, flat surface and get your car up on jack stands. I put mine up on 4 jack stands, so that later on when you are draining the oil, the car is already level and will drain properly.
Where to jack and put jack stands has been debated many times before.
2.) Once you get your car up on 4 jack stands, it is time to remove the brush guard. There are 5 bolts to remove and they are all 12mm.
3.) Now that you got your brush guard off its time to get under the car and start your oil change. You should take a second and locate the oil filter and the oil drain plug.
4.) If your engine is cool, go ahead and start it up and let it run for about 5 minutes. This helps with the oil change. The oil gets warm and drains much easier and quicker.
Banjo Bolt (Union) removal and install on a Subaru WRX STi:
This is Banjo Bolt step by step guide on the removal and installation of a Banjo bolt and new copper washers for a Subaru WRX/STi or any other turbocharged Subaru.The Banjo bolt is the one with a filter screen that others have indicated should be cleaned or replaced periodically. Subaru calls it a “Union screw (with protrusion).”
12 mm socket – for intercooler bracket bolt
14 mm deep-well socket – for up-pipe bracket nut and bolt
10 mm socket or wrench – for stock turbo heat shield bolt
17 mm ratcheting wrench – for Banjo bolt
10 inch or longer extension – to reach up-pipe bracket bolts
Start by removing any heat shields that are in the way. I have the SPT heat shield that comes off by removing the 12 mm intercooler support bolt.
(See pic “Engine bay area”). I also have the stock turbo heat shield installed. I didn’t take it off, but there will be a little more room to work if you do. A 10 mm socket is needed to remove the stock heat shield bolts.