thermostat question

[lorraine1]

on the thermostats what is the small pellet looking thing at or near the rim?is it to let air escape?or to help with overheating?

 

[koda2000]

on the thermostats what is the small pellet looking thing at or near the rim?is it to let air escape?or to help with overheating?

it's referred to a a "giggler". it's purpose is to allow trapped air to escape. when you drain and refill the coolant from the engine, air often becomes trapped near the top which causes initial overheating. on the SOHC V6 this often happens until/unless you "burp" the cooling system. this is a potentially harmful condition. for some reason Ford did not see fit to install a bleeder valve (like other manufacturers) to let the trapped air out. the giggler valve helps to get the air out. I've noticed that on the V8's, where the thermostat housing mounts vertically, there seems to be a slight recess in the housing to install the giggler near the top.