I just bought a used 2009 Toyota Camry LE from Ontario, Canada. I have only driven the car for 1 month in Nigeria and I am still using the Pirelli Winter tyres the car came with. While driving, I observe there is a lot of strange noise in the cabin of the car, and it increases with speed especially on the highway. I always have to increase the volume of my sound system in order to hear what is on radio or CD player. At speeds above 100 km/hr, I observe additional hum sound/impact similar to friction between 2 metal surfaces. My mechanic inspected and showed me that 2 of the mounts are due for change - one is at the vertical shaft that connects to the front left wheel and the second is behind the engine block inside the bonnet. Please, help provide guidance on what to do to fix this problem.
Well at the risk of sounding crass, I think you already know what you have to do. The winter tires will cause an excess of road noise on dry pavement. I doubt you will ever need them in the area of the world you are in, so would highly suggest you replace them with some good summer tires. The first bushing you are describing sounds like the strut mount at the strut tower. If this is worn out, it to will cause excessive road noise. The second bushing you are describing sounds like an engine mount or torque bar. Again, this is another item, if worn significantly, will cause an excessive amount of engine vibration to enter the cabin. Getting all three of these things replaced should greatly reduce the amount of road noise/vibration you are hearing when you drive.