GWLegacy

The most IMPORTANT issue is NOT the oil quality or the oil grade, it is the use of the original OIL COOLER, which is not standard on all Subaru engines. To call the standard Subaru oil Cooler an oil cooler is incorrect as it is a HEAT EXCHANGER in the pure sense of the word. By changing any type oil in your Subaru engine at the very longest 5,000 miles or every 4 months which ever comes first you will eliminate ANY oil problems. Subaru engines by design are very stressed engines and the OIL is its life blood. More so than any ford or chev V8. Because the oil galleries, Variable Valve timing systems on the end of each cam shaft, bearing clearances and oil filter very close to the exhaust system came cause oil degradation which causes bearing failure and turbo failure, both of which require OIL in large volumes and EVEN tempreture. ANY spike in oil tempreture will cause engine failure. The internal design of Subaru DOHC engines require the FACTORY Oil Cooler ? Heat Exchanger to be installed, with or without a turbo charger fitted. The failure of most Subaru engines can be caused by Oil Degradation caused by LACK of this critical component. Oil grade can ave an effect BUT it totally depends on outside tempreture, so Arizona is different to Montreal. The Oil Cooler is a Preheater in the winter and a Cooler in the summer. Changing the recommended oil regularly and the correct grade for your area will eliminate premature oil failures. If you don't have a factory oil cooler your engine will run Number 3 bearing or the turbo charger. Yes you can purchase the factory cooler and fitting kit and have it installed no problem.

Can anyone tell me why Legacy GT do not come with an engine oil cooler fitted as per Subaru Engine manuals. The lack of an Engine Oil Cooler will cause the engine oil to denigrate and has been found to cause big end bearing failure in 2 ltr GT engines from 15,000 kms to 135,000 kms. I have used Mobil Synthetic One and fram filters every 5,000 kms and my engine ran the No3 big end bearing. On investigating I found this is common fault and most engine reconditioners have had engines fail in the bearing at very low Kms. Have other owners of Legacy GT models from 2004 to 2008 had this premature engine failure.