lately i noticed that in my coolant reservoir theres this gunk on the cap and around the inside. its kinda like oatmeal or something. what could this be from? im thinking if i flush the whole system that should take care of it. how do i do that?
Assuming that it's just crud, you need to flush the cooling system completely and then change it out more often. I'm not sure if there's a write up, other than for heater cores, do a search or maybe someone can post the link here for you.