Please help, My 1990 SSP Mustang has an overheating issue.

[dougphillips48]

Is the carpet on either side damp? Is there a strong smell of antifreeze inside the car? Does the windshield fog up? These are all indications of a leaking heater core. If nothing inside is wrong, check the small heater hoses at the back of the engine that connect to the heater core through the firewall. The oil cooler is another possibility if the radiator and top and bottom hoses aren't leaking.