Check or better , change the thermostat.
Yes
( 20.0 U.S. gallons ) according to my Chilton's book for a 1989 Ford Crown Victoria
For a 1989 Ford Crown Victoria : For the 5.0 litre / 302 ( and the 5.8 litre / 351 ) ( With engine oil filter change , 5 U.S. quarts , according to my Chilton's book )
Yes, they are identical
could be the the headlight switch, dimmer switch, headlight relay, or a problem with the wiring
On a 1989 Ford Crown Victoria : ( there are 5 lugs per wheel , total of 20 )
C-4 aod
147 hp
About two tons.
According to my Chilton's Auto Repair Manual : A 1989 Ford Crown Victoria has a ( 20.0 U.S. gallon gas tank )
http://www.modifiedlife.com/1989-ford-crown-victoria-car-radio-wiring-schematic/ any car audio web page will have diagrams