technically it will but that is not a reason to not go for the faster hard drive. First, the heat difference will be rather small, and second, it would only be noticeable if you compared the 2 when running a big file write like copying a load of files from a network or something.
if you want to worry about heat just find out from people who have used the laptop model before... because either the design will be made to prevent or reduce heat problems or the laptop will get hot regardless of the HD.. but just b/c of the design.
Will a 5400 rpm hard drive produce more heat than a 4200 rpm HD? How noticeable will it be?
And if HD brand is required let's say it's for a Fujitsu S series model. thanks.