Mustang Radiator Overflow Tank (1965-1973) Installation Instructions

Tools Required:
  • 3/16-inch Drill Bit & Drill
  • 7/16-inch Wrench
  • 1/4-inch Drive Ratchet
  • 7/16-inch Socket
  • 1/4-inch Rubber Hose
  • Scissors & Razor Blade
  • Flat Head Screw Driver
  • Rivet Gun
  • Marker
  • Safety Glasses
Install Difficulty:
  • Moderate
  • Moderate Project
1. The first step to installing your new Mustang radiator overflow tank is to take all the parts out of the box and take inventory.
Mustang Radiator Overflow Tank Install Image
2. Bolt the brackets to the tank and take it out to the car to mount it.
Mustang Radiator Overflow Tank Install Image
3. You’ll want to make sure your car is cooled off before going any further. Find a spot inside the Mustang engine compartment where you want to mount the tank, hold the tank there, and mark four dots inside the bracket holes. These will be the locations for the holes you will be drilling. Make sure you pick a location where the longer of the two tubes is not over any hoses, wires, or support braces, as this is where hot coolant will be coming out in the event of a boil over.
4. SAFTY FIRST: Always wear eye protection when using power tools. Now that you have your location, drill a hole at each marking. Make sure there aren't any Mustang electrical & wiring, or fluid lines behind the drill location.
Mustang Radiator Overflow Tank Install Image
5. Rivet the tank to the car, or bolt it to the car near the Mustang radiator. I chose to use nuts and bolts instead since I don’t want it fixed permanently.
Mustang Radiator Overflow Tank Install Image
Mustang Radiator Overflow Tank Install Image
6. Remove the Mustang radiator cap and locate a plastic hose coming out from under the radiator cap. Use your razor blade to cut it off the attached nipple. On mine, the plastic hardened and the hose a broke off long ago.
Mustang Radiator Overflow Tank Install Image
7. Attach the new rubber hose to the nipple and clap it down using one of the hose clamps. Feed the hose out of the way between the radiator and the Mustang radiator support brackets. Two to three feet of hose will be more than enough. Replace the radiator cap.
Mustang Radiator Overflow Tank Install Image
Mustang Radiator Overflow Tank Install Image
8. Cut the rubber hose to length now. Attach it to the shorter of the two tubes on your new Mustang radiator overflow tank and tighten the supplied camp.
Mustang Radiator Overflow Tank Install Image
Mustang Radiator Overflow Tank Install Image
9. This completes the installation of your new Mustang radiator overflow tank. Note: In order for the system to work properly you MUST be using a vented radiator cap. A non-vented cap will not allow coolant to return to the radiator from the overflow tank.
Mustang Radiator Overflow Tank Install Image