Electric fan setup/wiring.

[Hellrot]

Hi. I recently purchased an M3 that has an electric fan, and "rongineering" electric fan kit (activates fan 5 seconds after brake pedal is pressed). The viscous fan is deleted, I have a CSF aluminum radiator and there is no fan shroud. Sometimes the temp creeps up above half but never over 3/4 when idling.

I'm thinking of wiring the electric fan with a coolant temperature switch. Any recommendations on this setup (what temperature coolant fan switch, where to mount the coolant fan switch, there is a spot on the thermostat available and 2 spots on the bottom of the radiator on the drivers side)

Do you think I should install a fan shroud??


Thanks in advance.

[evanboyle]

VAC Motorsports sells a nice kit with relay’d wiring harness, an 88*C ‘low temp’ fan switch, and brackets. I think they sell the harness / fan switch sensor searately.

I mounted mine in the bottom of the thermostat housing and it all works perfectly. Using the included 14” SPAL puller fan with integrated blade guard doesnt require a shroud however if your current elec fan is unprotected a shroud is very nice to have.

[mlytle]

what am i missing....why would a fan be set up to come on when the brake pedal is pushed?

it should be connected to a switch mounted in the the T-stat.

[jimmy p.]

what am i missing....why would a fan be set up to come on when the brake pedal is pushed?

it should be connected to a switch mounted in the the T-stat.

OK so I am not the only one that made my right eyebrow go up at that?

[evanboyle]

Yea, what happens if the car is sitting parked in neutral? Go ahead and overheat?

[Hellrot]

http://www.rongineer.com/m3fankit.html

Thats the setup it has now... I was thinking the same thing when its in neutral its going to overheat.

[Hellrot]

VAC Motorsports sells a nice kit with relay’d wiring harness, an 88*C ‘low temp’ fan switch, and brackets. I think they sell the harness / fan switch sensor searately.

I mounted mine in the bottom of the thermostat housing and it all works perfectly. Using the included 14” SPAL puller fan with integrated blade guard doesnt require a shroud however if your current elec fan is unprotected a shroud is very nice to have.

do you have a link to this kit?

[mlytle]

https://www.vacmotorsports.com/

[evanboyle]

$399 for the full kit with fan, brackets, harness, 88* temp switch: https://store.vacmotorsports.com/mob...-m3-p1773.aspx

pic installed in my car:

[Hellrot]

I contacted VAC to see if they will sell me just the wiring kit + sensor, without the fan. Waiting on response.

I also want to replace the hoses with silicone hoses. Any recommendations? Mishimoto hose kit?

[mlytle]

there is no magic in a fan wiring kit. some wire. a relay. a bmw t-stat switch. simple and cheap to make.

even easier for you. you have it all in place except for the t-stat switch. reroute the "brake switch" wiring to the t-stat switch. done.

[evanboyle]

^^What mlytle said regarding the re-use of your current setup using a temp switch as the gate control / trigger for the relay

As far as hoses go mine are Samco and can be sourced from a bunch of places. VAC sells them for $360 and supposedly have em in stock.

[Hellrot]

there is no magic in a fan wiring kit. some wire. a relay. a bmw t-stat switch. simple and cheap to make.

even easier for you. you have it all in place except for the t-stat switch. reroute the "brake switch" wiring to the t-stat switch. done.

I swear you're a genius... everything is setup ready to go like you said! Just need a low temp sensor and I'm all set.