Thermo switch

[e30 335i]

hey i have an m30 b34 swapped e30 and currently have thermos hooked up to accessories running constantly with a problem but would like to hook them up to a switch i could either put in the thermostat housing or on one of the switches on the side of the radiator maybe? opinions?

[LowR3V'in]

Your post is alittle hard to understand.

What temp switch do you have currently?
Perhaps get a hotter one if it turns the fan on at a to low
of a temp.

[e30 335i]

hey Lowrevin as stated above the fans are hooked upto accessories running constantly....... i have a 72 degree thermostat

[LowR3V'in]

I think I get what you're trying to say.

So you have a 72c thermostat and your fan is intentionally
wired to be on with the key on?

I'd use the right thermo switch on the side of the radiator so it'll only
turn on when there's a need. Or use an aftermarket switch.

72c (160f) is barely out of warmup. Why so low?

[e30 335i]

hey lowrevin yes it is intentionally wired to the key, i have a 72 degree thermostat coz during summer i rarely see anything under 30 degrees celcius the car runs about 175 around town. The 2 switches on the right hand side of an e28 535i radiator what temperature are they set for?

[wildstoats]

hey lowrevin yes it is intentionally wired to the key, i have a 72 degree thermostat coz during summer i rarely see anything under 30 degrees celcius the car runs about 175 around town. The 2 switches on the right hand side of an e28 535i radiator what temperature are they set for?

Per the e28 Bentley manual:

Low Speed Switch - White Switch Body - 196F (91C)
High Speed Switch - Red Switch Body - 210F (98C)

Hope that helps.

[e30 335i]

thanks wildstoats, i might have to try and find a switch to put in the thermostat housing coz 91C and 98C are a little late for a fan to be switching on for a hot day. Any ideas what motor i could get a switch for the thermo housing out of? Im going on a 14 hour trip in a coupel of weeks so trying to get it sorted.

[wildstoats]

Not off the top of my head but let me check my documentation and see if I can find something. Just out of curiosity what temp is your thermostat?

[jlevie]

A lower temperature thermostat only changes when the thermostat starts to open in hot climates. The steady state temperature of the engine in a hot climate will be the same as when a normal thermostat is used. I'd switch out the thermostat for an 80C unit, which I believe is the OE thermostat for that engine and replace the 91/99C thermo switch with one rated for 82C.

I assume you are using the aux fan for cooling. It is a less than an ideal solution as a good bit of the air it moves can escape rather than go through the radiator. If you don't use the A/C, the condenser and aux fan can be replaced with a 16" fan rated for 1800CFM (or more) installed in a shroud that covers the front of the radiator. If you do use the A/C, retain the aux fan and the 91/99C switch and restore the aux fan to normal operation. Mount an electric fan in a shroud on the engine side of the radiator activated by an 82C thermos switch..

[e30 335i]

hey jlevie the thermostat im using is fine for what im after, i am using a 10inch and a 12inch thermos on the front of the radiatorand happy with that. All i want to find out is if there is a switch from a later model bmw that will fit in the thermostat housing to roughly switch on about 185F(85C)

[LowR3V'in]

By thermos you mean fans?
I know for sure that e30/e36/e34 sensors fit in the e28 rad. , and probably many others.

[e30 335i]

Yes thermos are fans what else is going to be 10inches and 12 inches mounted on the front of a radiator? I stated im after a switch to turn on the fans at 185F THAT MOUNTS IN THE THERMOSTAT HOUSING, not the radiator coz it is not the most accurate place for a temperature reading. Does no one understand the question im trying to ask?