Not likely at all that both thermostats are bad.
Are you sure you have bled the air out of the engine?
You are pretty much down to
(1) radiator plugged or partially plugged
(2) internal engine problems, cracked head or block, blown head gasket, etc.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.