What about decreasing the temperature rating of the thermostat? These are generally not needed by the average or above average user. These are more for advanced users with greater cooling requirements due to racing applications or highly modified vehicles. When you get to this point, you will find the shortcomings of the OEM cooling system and will determine which thermostat best suits your needs. This link and this link provide lot of good information on switching to a cooler thermostat. Many also consider this to be a reliability modification even on a stock vehicle.

What about aftermarket radiators? These are generally not needed by the average or above average user. These are more for advanced users with greater cooling requirements due to racing applications or highly modified vehicles. When you get to this point, you will find the shortcomings of the OEM cooling system and will determine which radiator best suits your needs. They are a great upgrade for the weak plastic end tank equipped OEM radiator though, so if OEM failure occurs, an aftermarket unit is worth looking into.

What about aftermarket or “slim” fans? Just say no. Always use OEM fans as aftermarket fans usually negate the good effects of an aftermarket radiator. This thread shows the basics of stock fans = good, aftermarket fans = bad.

How often should I change my coolant? Refer to and use the maintenance schedule in your owner’s manual for Subaru coolant. For other coolant, refer to the coolant manufacturer’s recommendation.

How do I replace my coolant?