[SoCalVWadam]

i have a overheating problem but fan only kicks on if running air, there is a leak in my thrmoswitch going into engine coming from top rad hose wondering if the no pressure would keep fan from running already switched water pump, water pump housing, and thermostat no leaks was wondering also if just could be the switch at the bottom of radiator

 

[ps2375]

Re: air leak in cooling system (SoCalVWadam)

Very well could be the fan switch.

 

[kamzcab86]

Re: air leak in cooling system (SoCalVWadam)

Remove the electrical connection on the thermo switch in the radiator. Jump the connections in the electrical harness (red wire to one of the other wires); if the fan runs, the thermo switch is bad.