bounces form 1/4 to 3/4 all the time. no looks found. bad themrastat? temp sensor?

Make sure the coolant system is bleed properly. Air in the system could cause this.

where do you bleed it? lt is leaking out the cap it seems.

is there a check valve anywhere?

Get a chiltons guide.

there are two small bleed screws, one on top of the thermostat and the other on top of the rad hose.

If the cap is leaking then it needs to be replaced.

replace the rad cap and fill the rad crank it up there is a small fitting in the black heater by pass tube right above the waterpump. it is brass hold the bigger fitting and turn the little center fitting to the left until coolant comes out the go over on the thermastat housing there is another bleeder do the same . then go back to the one above the water pump and bleed it . do this until just coolant comes out of both.if it still does it then replace thermastat with one made in the usa .do not put one made in mexico in it as you will end up replacing it as it will not open