Hummmmmm... you know I can't remember butt......maybe it comes on @ 150* off @ 160*.Regardless...it does cycle off and that is only in stop and go  summer weather. Highway and/or cool weather it never comes on.
I guess my question was should I change either the thermostat or the  sensor so they BOTH will be the same degree?
Or "let sleeping dogs/ponys lie"?!
6s6

Running too cold of an engine presents problems of condensation and oil sludging because the oil doesn't get hot enough to flash off the moisture inside the engine.

It will also present more incomplete combustion, since less of the fuel in the air/fuel mix will be ignited and burned and more raw gas will be sent out the exhaust pipes.

If you like power, running a cold engine will not produce as much power as a hotter engine --and I'm not talking hot as in boiling the water out. An engine in the 200° range will produce more horse power than one that's operating at 180°.

The most technologically advanced engines of today are still only about 20-21% efficient. This is because nearly 40% of the gross horse power produced by the engine is lost to the heat being expelled from the combustion chambers and out the tail pipes. Another approximately 40% of an engines total power is lost to the thermal drop inside the combustion chambers, due to the coolant circulating through the passages around the cylinder heads and the cylinder bores (Ideal Gas Law).  A hotter combustion chamber/cylinder bore produces a more powerful explosion to thrust the piston downward and to push the crankshaft with a more powerful force.


http://mb-soft.com/public2/engine.html

I've gotta agree with Ultra and DC,  my 95 engine from the factory runs a 195 stat and the 2 speed doesn't even switch low on till 212.
Now I have fiddled with that in the chip, but not by much.

Sal, I'm scratching my head on this one... It seems to me...

1)  If the fan temp switch is "on" at 160, the fan will turn on 35 degrees before your 195 thermostat opens,  and will stay on until your engine cools down below 160 (30minutes after you shut down).

2)  With the temp switch located in the back of the manifold, the switch is located at the farthest point from the radiator & fan.... I think a better location for a fan temp switch might be in the lower part of your radiator or in the lower hose.  Then, you give your radiator a chance to reduce the coolant temp, and if the air moving over the rad is insufficient to reduce the temp in the rad, the switch will kick on the fan.  It seems the way it is currently set up, the fan can turn on or off with the switch having no idea of the coolant temp in the radiator.

Are you trying to get MS to chime in on this one????
 

It would be more like ON at 200, OFF at 195. You have to keep enough spread between the OFF setting and the Thermostat operating range or the electric fan will never turn off after it is triggered on.

6sally6 wrote:

Hornman wrote:

It would be more like ON at 200, OFF at 195. You have to keep enough spread between the OFF setting and the Thermostat operating range or the electric fan will never turn off after it is triggered on.

This is with a 190* thermostat...correct?!
6s6
 

 
Correct.

Sal, I'm a proponent of the 160 thermostat also, and my e-fan is set to come on at 185 and go off at 170.  My experience has been that it's better to start managing heat early rather than late. And all a thermostat does is allow you to start managing heat. The system will run at whatever temperature that combo dictates.

The primary purpose of a radiator isn't to cool an engine but is to keep the engine at optimal operating temperature. The thermostat is the 'brains' for maintaining this optimal temperature.

The temperature rating stamped on the thermostat isn't the figure at which the thermostat will be fully open. It's the cracking temperature --the point at which it will start opening. The wax motor won't drive the thermostat to being fully open until the water temperature has risen 20° above what's stamped in the thermostat.

6sally6 wrote:

ultrastang wrote:

The primary purpose of a radiator isn't to cool an engine but is to keep the engine at optimal operating temperature. The thermostat is the 'brains' for maintaining this optimal temperature.

The temperature rating stamped on the thermostat isn't the figure at which the thermostat will be fully open. It's the cracking temperature --the point at which it will start opening. The wax motor won't drive the thermostat to being fully open until the water temperature has risen 20° above what's stamped in the thermostat.

WAX MOTOR?..You lost me Ultra
6s6
 

 
There's a wax pellet inside the thermostat assembly that as the coolant heats up the thermostat, the wax expands and pushes the piston of the thermostat open, to allow the water to circulate. As it cools off, the wax contracts and the poppet reduces the opening or closes off.

http://auto.howstuffworks.com/question248.htm

Jimj wrote:

6sally6 wrote:

Hey Jimi!!!  Welcome to da forum!!
Soooooo it looks like me and you pal!!
No seriously....How has the lower temps(160*) worked for you? Any sludge build up issues?
What kind of  set-up do you have?!! 5.0......351......FE?
6saly

Sal, I've been a member here for some time, but don't normally post much.

I'm running a 331 inch smallblock, aluminum heads, 10.5-1 compression, Hilborn stack EFI injection with Holley ECU,  ahead of a TKO600 and a 9" with 3.89 gears, all in a 1965 fastback with a .565/571 lift roller cam.
I'm not worried about sludge as my car only sees about 2-3K miles per year and that's with two oil changes per year.  Maintenance is your friend. 

I've always found cooling issues to be one of two things, insufficient air flow, (indicated by temperature creep at low speeds, but acceptable temps at highway speed), or  insufficient cooling capacity, indicated by temps staying at higher levels.  Now keep in mind that higher levels and too cool are subjective and everyone has their own opinion.  I run a 160 stat and am happy with it. Others are happy with 180 or 195 stats, go for it.

Most drag racers that I know like to enter the burn box at around 170 degrees.  The dyno operators I know like to start the pull at a minimum temp of 170 or 180.  The higher temps encountered from 70's to current is to lower the amount of emissions, not to increase performance. A hotter chamber will burn cleaner.

Good info!!
Thanx
6s6