Baseboard heater noise is actually a very common issue. That does not mean, however, that the noises coming from your baseboard heater are just a part of the system. Noisy baseboard heaters come from a number of reasons but generally do not mean that your system is on the verge of shear and utter collapse.
A common baseboard heating noise is pinging coming from the area of the baseboards themselves. This pinging is most often caused by the fins that run along the baseboards. If the fins are bent or pushed together they will begin to rub against the other fins or the baseboard housing as they expand and contract with the heat cycles.
Another common reason for baseboard heater banging is a build up of air pressure in the system. As the system pulls in water it will also pull in air. Over time this build up of air pressure will cause a banging sound in the pipes of the baseboard. Do not worry though, because baseboard heating systems have an air pressure release valve, also known as a bleeder valve. The air pressure should be removed from your system at least once a year and should help to quiet that noisy baseboard.
Finally, it is also a good idea to thoroughly vacuum and clean the baseboard heating unit throughout the heating season. Keeping the baseboard clean will help keep the heater running smoothly and efficiently.
If none of these solutions help to eliminate the noises coming from your baseboard heater you should contact a qualified service technician in your area. The technician will be able to perform a thorough diagnosis of your system to determine the cause of the noise. He or she will be able to repair or replace any malfunctioning portion of your system and get it running (quietly) in no time.