1996 Subaru Legacy How can I check if my waterpump still ru

Hello, I want to check if my waterpump still runs proper. Just bought this car not formiliar with brand. After the car has been running water reservoir is full after few hours its half empty. It doesn ´t overheat the engine according to the temp. Meter.

Also there is a burned fuel smell with very light smoke coming from underneed the engine near the exhaust on the left top side of the engine. Is this a leak in the exhaust or fuel injectors etc.

Thanks you