thermostat, electric fan coordination

[emac]

My carbed 351W has a 185° thermostat. Or at least it performs like one. The electric fan runs pretty much all the time after the car gets to 185. I am using the fan thermo switch from ffr. The car stays around 185 - 190, consistently. Should I:

1. Get a higher fan thermo switch that comes on at 200 and off at 185.

Or

2. Get a 170 or 180 degree thermostat and keep the thermo switch I have.

It gets pretty hot here in SC , so I tend to lean towards cooler thermostats, but I don't want the motor too cool. I appreciate all input. As always thank you!

[2FAST4U]

I think you're fine with your current setup

[CraigS]

Agreed, I wouldn't change a thing. One thing to keep in mind is that in our FFRs we see actual real temps on the gauges. In your daily driver the gauge is damped so it stays in the middle until about 10 seconds before it blows water out. All the manufacturers do that cause it cuts WAY down on customer complaints. I sometimes feel like figuring a way to damp my FFR gauge cause I pay too much attention to it.HTH

[Bob P]

The question is, does the fan shut off when the car is at speed? If it doesn't, either lower the thermostat temperature or raise the fan switch temperature.

[tirod]

Actually, leave the thermostat alone. 195 is what it should be at. Combustion efficiency is the key, not whatever temp a fan is running. The closer it can efficiently run near 212, the better. The radiator cap gives some cushion anyway, adding another degree per pound of pressure as insurance against boiling.

It is an important question - does the fan cycle off when speeds over 30mph are sustained? The car moving thru the air at that speed should be sufficient to pass enough air thru the core, cooling the car. It's why mechanical fans have clutches to free wheel the blade, or the blade flatten out to reduce the pull. Given proper sizing and a working pump, you don't need a fan over thirty mph, just under it.

About the only way to know the fan isn't kicking off is to have an indicator light wired into the circuit, or hear it. Rather improbable the fan could be heard with the typical outside exhaust rumbling under the driver's ear. How do you know the fan is staying on?

[emac]

Thanks for the replies. The fan seems to continually run. I can hear it at stop lights or when I am pulling into the garage. I am pretty sure it is running even at speed.

I have a manual fan switch on the dash in addition to the auto switch . I disconnected the auto switch and drove around today. The temp would slowly climb in traffic and sitting still. I would flip the fan on at about 195. thermostat alone kept the car at proper temp except when it sat for an extended time. From what I read and you guys posted 190/195 isn't too hot for motor. That was my main concern.

I ordered a thermo switch from summit racing that comes on at 200 and off at 185. That may work with my current thermostat. what do you think?

I know what you mean about having a real gauge.....it really keeps your attention. My old BMWs used to work that way, but they started buffering them and drove me crazy. Thanks for the replies.

[d42davis]

This is unlikely to fix your problem. You need a larger gap between thermostat range and switch range. The thermostat will likely modulate to hold the water temperature between 185 and 190, given natural air flow from the car moving thru the air. If you stop in traffic and water temperature rises to 200, the switch will close and the fan will come on. No matter how hard the fan works or how fast you drive, it is unlikely the water temperature will drop below 185 to allow the fan switch to cycle off.

[Bigtim01]

Is this an EFI or Carb car The temp for these two are different.
Tim

[emac]

Originally Posted by Bigtim01

Is this an EFI or Carb car The temp for these two are different.
Tim

Carb