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Guest Anonymous

more fan/coolant questions

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Guest Anonymous

I'm trying to get a proper sensor going for my cooling fan as

many of you know. So far the two wire sensor on the engine

doesn't kick in soon enough, nor does the 320i radiator

sensor. I don't really want to use a sensor that plugs into the

radiator either-nothing wrong with them, just want to go a

different route. My questions are-what are the routes the

coolant travels in the two operating conditions, i.e. stat open/

stat closed. Can I interrupt one of the hoses by splicing in a

piece of brass or aluminum pipe and threading in a boss for

a "3/8" npt sensor from summit? Are there any more practical

solutions for kicking in an electric fan. Yes, this is basically

the same question as before but nothing's working so far.

thanks again.

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Guest Anonymous

on the outlet of the radiator. When stat is closed the coolant by-passes the rad and goes direct to the engine. Once coolant is up to temp and stat opens coolant goes to the rad. If the coolant is a bit high temp on the outlet of the rad, I'd think that would be where you would want a sensor. Probably the best place also as it can support off the stub from the radiator.

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Guest Anonymous

the hose that connects to the top of the thermostat is long enough for a thermoswitch coupling. This is a BMW part and I don't know the number or which yr 320 it was used on. I lucked out when I needed one. I went to a local pic-n-pay and started looking for one and someone had removed the coupling and placed it on the fenderwell. But it is threaded for the thermoswitch.

If you're using a 320 radiator and mounting the thermoswitch in the bottom of the rad I think it could be done w/ an 82c switch as the coolant is much cooler by the time it reaches the bottom of the radiator, but I haven't tried. However I did try a 91c switch there and it never activated the fan at a reasonable engine temperature. By the time the coolant heated to activation the engine temp was near 220f. With the 91c thermoswitch mounted at the top of the motor the fan is activated at about 200f.

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Guest Anonymous

I have the same setup - 82 degree C sensor in the bottom of a 320 radiator. Works very well.

Good Luck,

Mike (#87)

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Guest Anonymous

you're using a BMW unit, the ones with white tops are low temp, red tops are high temp. The project car's cooling system has a 2 sensor/2 speed fan circuit (low temp/low speed, high temp/high speed), and so far, no matter how long the car idles (even on a 100 degree day), the high speed circuit never comes on.

The other car has a one speed fan circuit with a low temp sensor in the water jacket in the bottom of the intake manifold - it kicks the fan on at about 190 degrees F.

If you're using a high temp sensor, it may be the reason your fan doesn't come on.

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