The air-conditioning system of my BMW 325e might not be in its best condition anymore. Whenever I switch it on, there's this strong, unpleasant smell flowing inside the cabin. What could be wrong with my car's air-conditioner? What part of the air-conditioning system should I check in this case?
The foul odor from the air-conditioner could be coming from the microorganisms that have already built up or settled in the A/C's evaporator. These microorganisms, along with dirt and other particles, contaminate the air that's blown into the passenger cabin of the vehicle. The pungent odor isn't the only thing you should worry about here. The microorganisms and other contaminants may also cause allergies, which could trigger coughs, sneezes, sore throats, and other allergic reactions. To remove the bad odor and prevent the spread of allergies, the air-conditioning system of your BMW should be treated, killing off the microorganisms that have infested the evaporator and other A/C components. This service should be done by a qualified car air-conditioning specialist or auto service facility if you don't have the proper tools and equipment, enough experience, and the needed automotive know-how.
When the brakes of my BMW make noise or vibrate, what does this usually mean? Is this bad news, or is this normal?
The noise the brakes make could indicate different kinds of problems. For instance, the pads are probably worn out when the brakes squeal as you step on the pedal. It may be time for you to replace the thin pads before they cause damage to the rotors. Sometimes, the noise could be harmless. When the brakes squeak, it could be because the brakes are already dusty or the humidity level is high. If the noise becomes more noticeable and more frequent, however, this shouldn't be ignored. The brake system should be inspected to figure out the problem early on. If there are pulsations or vibrations when you hit the brakes, you could be dealing with warped rotors, which could be turned to smooth out the surface or could be replaced altogether if they're already deeply grooved or badly damaged.
Would it be fine to use just two winter tires on my BMW instead of getting a complete set for the rear and front tires of my vehicle?
Most car manufacturers, including BMW, highly advise that you to install all four winter instead of just using two for the front or for the rear. By replacing all four tires and making sure that they're matched and not mixed, the vehicle is able to maintain balance in all four corners. This will ensure that vehicle handling will be even and more controlled, which is crucial when driving in winter when roads are wet and slippery. This allows you to have even traction on the front and rear and all sides. With firm tire-ground contact, it'll be safer to drive the vehicle. Steering and suspension would be better. You can also take full advantage of the ABS system or traction control if all four tires are replaced.