Q: Hi, my name is John. I just took in 2008 Lexus ES350 for oil change, and the mechanic at Firestone is telling me that there are ga

Hi John. Thanks for writing in today. The CV boot protects the CV axle from dirt, debris and maintains lubricity as it contains a copious amount of grease. It will wear out overtime - due to exposure to elements, road grime and can wear prematurely in areas where sodium or mag chloride (road salt for de-icing) is used. The boot will eventually crack - and frequent use (or the simple act of turning the steering wheel) will tear the boot. When this occurs, the grease inside will "spill" and splatter under the wheel well and on other components. If the torn boot is found quick enough, then the boot itself can usually be replaced as long as there is no damage to the CV joint. Best practices suggests to replace both CV boots or CV joints (if they are damaged) as they will wear out about the same time. Hopefully this answers your questions, but if there is anything else we can help you with, please let us know.