Our 87,000 mile 2005 V6 Highlander is about to get a Toyota replacement timing belt. One dealer says to also change the water pump, drive belts and crank seal. I understand the justification for the water pump and the drive belts but the crank seal? Should that be necessary on a mildly driven 2005 Highlander? Since replacing the drive belts and crank seal run the price up by an additional $206, I can do the drive belts. Is it necessary to change the crank seal? THANK YOU!