REPLACE EXPANSION TANK

there is another spring clip you have to get from the bottom and a temp probe. if you remove the oil cooler to one side it's much easier.

Do you have automatic transmission? If so, there is a secondary thermostat for the transmission cooler right where you are having trouble disengaging it. Be careful, and I recommend you do it yourself. The place I go to broke this small plastic thermostat while replacing my leaking expnasion tank and cost me an additional $100 unnecessarily. They claimed the thermostat "was already broken." Yeakh, right. Alternatively, point this out to the place you are taking it to. Unfortunately the TIS instructions for expansion tank replacement are not very detailed.