ok I found this 180 on 165 off switch but it says to put it in the oil line and i really dont like that idea so is there a coolant line that i could splice this into? if not where can i get a good cheap 180 on 165 off fan switch? i would really like to find one that would thread into the hole in the back of the water pump housing where that choke temp switch is.

http://cgi.ebay.com/ebaymotors/DERAL...item4cf1f19f3d

 

oil line? all the ones i've seen use a probe that attaches to the rad core. and those probes r quite long so no way could it be used in the pump housing. i have a mechanical temp gauge that i put the probe in the back of the pump housing. can't see that working that well since the coolant in the rad is what actually cools the engine and not the oil.

 

You really want one that pushes into the rad fins and is adjustable, if that one is set to shut off at 165 it will never shut off, once the engine is up to temp it should stay at a constant 180 (thats what the thermostat is)
I am running one similar to this and have had no problems with it:
http://cgi.ebay.com/ebaymotors/DERAL...Q5fAccessories

 

There are ones available to thread into the pump housing, but I didn't know if the thread pitch was the same as the housing so I bought the probe type. This one was designed to go into the upper rad inlet (outlet??) and clamped in place under the hose. You definitely want an adjustable one.

 

Actually, it's both; on a rotary, about 50% of the critical cooling load is borne by the oil system. Since there's no way to water-cool the rotors, they are cooled near-exclusively by oil flow (they're also cooled to lesser degree by the intake airflow).

This is why going low-oil in a rotary can be so destructive so fast; it's not just lube loss (bad enough!), but also rapid overheat of seals, seal slots & seal springs, with resulting loss of clearances and failure of spring resiliency.

In the FBs, the beehive does transfer oil heat to coolant as well as to the air via it's radiating fins, but in the SA, the FMOC bears the whole load.

Which is why I have an aftermarket oil temp gauge, in addition to the stock water temp gauge.

 

I heard the probes werent all that accurate and on most of the e-fan threads on here say that its best to have a switch that will kick it off at a lower temp that way your fan wont keep kicking on and back off.

 

so it may not be a bad idea to run it off the oil temp? but is the oil temp generally the same as the coolant temp?..... I hope thats not a dumb question

 

The oil handles about 30% of the cooling load, not 50%. I have a probe style fan switch on the widebody that's mounted at the bottom rear of the radiator near the lower radiator hose. This is where the cooler coolant goes from the rad to the engine. I set the adjustable thermostat for the fan by the aftermarket coolant temp gauge I have. It's set to come on at 180*

The oil and coolant don't necessarily run the same temp or follow the same rise/fall curve. I would never use the oil temp to turn the electric fan on/off, use the coolant. You can buy an adjustable thermostat at the parts store for 20-25 bucks.

 

I did specify "critical cooling load," but it's all good.