Electric fan thermo-switch mounting question (E21 -> 02)

[02Pilot]

I'm trying to mount an electric fan (from an E28) in my 02 so I can ditch the mechanical fan. I have a late E21 320i radiator installed (plastic/aluminum), and I'd like to install the temp switch that the E21s used to trigger the fan, but I'm not sure where it mounts (the parts diagram is unclear). There is a bung at the bottom right of the rad (don't know the thread pitch offhand) or I have a spare spot in the fitting at the front of the head where the temp sensor mounts.

I'm not sure about the temp range either - it may be dependent on the location (I figure about 80C at the bottom of the rad, or 90C at the head, would be appropriate).

Any thoughts, comments, and/or assistance is much appreciated. Thanks.

-Andrej

[ClayW]

I'm trying to mount an electric fan (from an E28) in my 02 so I can ditch the mechanical fan. I have a late E21 320i radiator installed (plastic/aluminum), and I'd like to install the temp switch that the E21s used to trigger the fan, but I'm not sure where it mounts (the parts diagram is unclear). There is a bung at the bottom right of the rad (don't know the thread pitch offhand) or I have a spare spot in the fitting at the front of the head where the temp sensor mounts.

I'm not sure about the temp range either - it may be dependent on the location (I figure about 80C at the bottom of the rad, or 90C at the head, would be appropriate).

Any thoughts, comments, and/or assistance is much appreciated. Thanks.

-Andrej

Use an 82C temp switch for an E21 320i in the bung at the bottom of the radiator. Bavarian Autosport has them for $17.95.

www.bavauto.com

[H_Krix]

How does that switch work? Does it just make continuity between the contacts when the given temp is reached?

This is something I'm in the midst of now as well. I've already ran a relayed line, so all I really need now is the switch.

[ClayW]

How does that switch work? Does it just make continuity between the contacts when the given temp is reached?

This is something I'm in the midst of now as well. I've already ran a relayed line, so all I really need now is the switch.

Yep, I noticed the switch in my 320i radiator (used) and removed it to test. It just kicks the fan relay on as long as the temperature is above the given setting.

The only X-factor (I think) is that you need a later 320i radiator with the bung for the sensor switch. Someone else might chime in here, but I don't think that the early ones have it.

[Guest]

you can probably drill and tap the thermostat housing and have the switch on there. That could work as well. That way you will not need to change out to different radiator.

[02Pilot]

Thanks. That will work easily. Now I just have to plot out exactly how I'm going to cut/bend/weld the right hood hinge support to get the fan in there and I'll be golden.

[Guest Anonymous]

I had a 320i rad in my 1971 Sahara. There are 3 temp. swithches available as I recall. We set up the electric fan to automatically activate per the sender( I think I had the mid-level temp switch), and we also led a manual override switch to the cockpit so I could stay ahead of a hot engine situation. I have pictures of it all in archves on Fototime( somewhere), and I may have sent them to FAQ when I knew how to do such things. ( It has been years since I have posted a pic). I was using an aux. fuse block from West Marine at the time for power connections in the engine bay( my battery was trunk mounted). Good luck- this is a good upgrade from the standard 02 rad. I found that the electric fan, alone, was not sufficient to keep my engine temps where I wanted. So, I added a 4 blade 1600 engine fan. But, I was using a weak electric fan. The cockpit override is a nice option to have. Email me for pics. kehoe2002at aoldotcom

[jimk]

you can probably drill and tap the thermostat housing and have the switch on there. That could work as well. That way you will not need to change out to different radiator.

The fan will probably run all the time if the sensor is put in the hot water outlet from the HEAD. Water flows out the head all the time whether the thermostat is open or not. The fan is supposed to run only when natural draft is not sufficient to cool the water leaving the RADIATOR. Running the fan all the time defeats the purpose for installing it if your intention is to cut the noise and to put power to the wheels instead of into the belt.

[mikem]

It has two tapped bosses instead of the one on a 2002. But, it does not have the water hose connection to the intake manifold (this never caused me a problem). I still had the water connections to the bottom of the intake manifold.

[TobyB]

Yeah, Jim's right-

the switch wants to be on the bottom of the rad.

No point in running the fan UNLESS the radiator needs help cooling

itself.

And if you want a truly easy pusher fan intstall for about 3#,

get an auxiliary AC fan from an early 80's Mazda 626.

You get to drill 4 holes- 2 of them invisible,

and then the fan just does its thing.

t

[ClayW]

Yeah, Jim's right-

the switch wants to be on the bottom of the rad.

No point in running the fan UNLESS the radiator needs help cooling

itself.

And if you want a truly easy pusher fan intstall for about 3#,

get an auxiliary AC fan from an early 80's Mazda 626.

You get to drill 4 holes- 2 of them invisible,

and then the fan just does its thing.

t

Can you post some pictures?

Also, do you (or anyone else) think that I could just replace my A/C condensor fan with a "better" (more modern) pusher fan and use it for both cooling and A/C duties?