cooling fan question

Hi All

is the anyone who could tell me for what reason someone would attach a very large what resistor 50 w 5 ohms about 3 inches long to the positive lead of the main cooling fan of a 95 century? the fan works but not very forceful a friend suggested it was done to slow down the fan and prolong its life. it turns on when the gauge starts to reach past the half way mark but I don't think it is very effective......any thoughts

thanks