Using your GrimmSpeed 1.3 Bar High Performance Radiator Cap is easy. First, make sure your engine is cool before you start. Simply remove the old radiator cap and replace it with the new GrimmSpeed cap. Ensure it's properly tightened for a good seal. Before purchasing, always double - check if it fits your Subaru model. This cap is made to last, but it's still a good idea to check the seal regularly for any signs of wear or damage. If you notice any leaks or the engine is overheating, check the cap and replace it if necessary. With proper use and maintenance, this radiator cap will keep your engine running smoothly and looking great.