In a large soup pot (12 cup capacity), add the water, potatoes, carrots, celery, onion, salt, pepper, and thyme.
Bring to a boil, reduce heat, cover, and simmer for 15 minutes (until the vegetables are some what tender). Do not drain.
Add the 1-1/2 cans of cream style corn, and the bacon. Keep covered, and cook over very low heat.
To make the white sauce: 1.) In a medium-size saucepan (over low heat), add the butter until it's melted. 2.) Then in a glass measuring cup or bowl, combine the milk and cornstarch; mix well. 3.) Raise the heat just a bit, then add the milk-cornstarch mixture, and keep stirring until it becomes somewhat thick. 4.) Add the shredded cheese, then stir until the cheese is completely melted. 5.) Add this to the corn chowder; stir and heat through thoroughly, but do not boil.