Hello, My Mk1 16v (which manages to spectacularly overheat when sitting in traffic) has a 2-pole fan switch and a 3-pole fan motor. The fan operates at high speed when the engine is toasty warm, but by this point is probably insufficient to prevent overheating. I have purchased a shiny new low-temp 3-pole fan switch from Awesome, which should (so I am told) cut in at a low speed when the engine is getting hot, and then at high speed when the engine is getting very hot. My question: The 2-pole switch has a red/black wire (to fan motor) and a red wire (live?). The missing wire is (I believe) red/white (to fan motor). Which wires go to which poles on the 3-pole switch please? I know that the red/white should go to the middle pole on the fan motor (probably), as this is the pole on the 3-pole motor that is currently without a wire... Thanks Adam
on switch: 1 - red/black - fast speed, fan pin 3 2 - red/white - slow speed, fan pin 2 3 - red - live feed on fan: 1 - brown - earth 2 - red/white - rad fan switch pin 2 3 - red/black - rad fan switch pin 1 Id say yopur problem is more likely the thermostat or the radiator though, the stock fan system should be more than capable of managing the temps. how hot does it get when driving along normally, and what temp does the fan cut in?
Thanks for that! :-) The stat is the correct KR one (i.e. same as the "low T" one sold by Awesome, I recall checking the marked temperature upon installation) and the bottom hose gets warm after only a few minutes so I know that it works OK. The fan cuts in when the water T gauge is 3/4 of the way around. Is it possible that my 3 T sender wires are in the wrong places? When driving normally the oil T is around 92-94 (additional oil-air cooler fitted) and the water hovers very slightly over 1/2 way. When stuck in traffic the water T creeps up and when it reaches 3/4 (after about 5-10 minutes on a warm day) I turn on the heater (nice and sweaty). After another 5-10 minutes the red coolant warning light goes all disco on me but fortunately that is also the point at which the traffic usually gets moving again so I have never had a proper steamy overheat experience. Admittedly the rad is the original 1989 one from the donor Mk2. Perhaps I should invest in a shiny new one! Coolant is about 50/50 G12+ and H2O.
3/4 is about right for the fan to cut in, the light might be an issue with the level warning sensor or perhaps the level is a little low
