Tape

Linerless Self-Bonding Rubber Tape replaces heat shrink tubing with a safe, tight, long-lasting seal that withstands temperature extremes from -50 to 300 deg F. It is stretched when applied and retains its elasticity to ensure a tight seal at all points. As long as it is stretched when it is applied, it will not unravel after application due to its self-bonding characteristics.
No heat guns or open flames needed
No paper liner to mess with
Unaffected by salt spray and common automotive fluids