The best replacement for radiator is intercooler.

The best alternatives to radiator are rated as following:
★★★★★  intercooler
★★★★  baseboard
★★★  copper
★★★  head gasket
★★★  forced air
★★★  water pump
★★★  heater
★★  thermostat
★★  ceramic heater
★★  convector
★★  heat exchanger
★★  fan heater
★  reservoir
★  condenser
★  radiator
★  space heater
★  furnace
★  baseboard heating
★  drain
★  towel rail
★  standard radiator
★  central heating
★  heatsink
★  oil cooler
★  forced air heating
★  electric heater
★  convector heater
  aluminum radiator
  freeradius
  downflow
  baseboard heat
  forced air heat
  copper brass
  aluminum
  2 row
  commodore
  convectors
  hot water
  heater core
  3 row
  gas fire
  3 core radiator
  copper radiator
  coolant tank

Your alternative for radiator is not listed? Suggest!
Speaking about radiator, one probably shouldn't forget about coolant.

Other search terms related to radiator and their ratings are:
★★★★★ coolant
★★★★ transmission cooler
★★★ towel rail
★ towel warmer
★ electric fans
You have in mind a companion for radiator and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of radiator in all years. Click on graph for more.
radiator
intercooler
baseboard