The reason water is inside your light lens is that the lens housing is cracked somewhere, not necessarily where you can see it, and when you either wash the vehicle or it rains, water finds its' way through the crack in the lens housing. If you can find the crack you can seal it with something as simple as silicone sealant.
No, it won't.
On a 1997 Ford Thunderbird : The odometer is in the middle of the speedometer
Your owners manual will explain how to reset that function.
According to the 1997 Ford Thunderbird Owner Guide it came from the factory with ( green color antifreeze ) Ford specification ( ESE-M97B44-A ) mixed 50 / 50 with distilled water
Its located behind the passenger Head light... its a huge pain to get to...
The 1997 Thunderbird 4.6L engine has only 1 catalytic converter.
According to the 1997 Ford Thunderbird Owner Guide : ( 18.0 U.S. gallons / 68.1 litres )
If it is a 5.0 from a 1991-93 Thunderbird/Cougar, then yes
In a 1997 Ford Thunderbird the 3.8 liter V6 engine has a timing CHAIN
On a 1997 Ford Thunderbird ( V6 and V8 ) 68.1 liters ( 18.0 U.S. gallons )
1997 Ford Thunderbird 4.6L SFI 8cylThe Spark Plug Gap.054 (In thousandths of an inch)
you might need to have it checked out by a mechanic to make sure nothing serious is wrong with it