Fan Run Time?

[JETAV8R]

I have a 180 degree thermostat in my 306. I am using the FFR supplied fan switch and RF wiring harness and it is mounted in the intake manifold. It's my understanding that this switch turns on at 185 degrees and turns off at 165 degrees. My car doesn't seem to have any cooling issues as the temp is always between 80 to 90 degrees C indicated on the temp gauge. My concern is that once the fan does come on, and I happen to shut the car off, the fan runs for what seems like forever in the garage. Basically until my engine cools to 165 degrees. Is this what everyone else is experiencing? Just seems odd to park the car and come back and the fan still running. Should I consider a switch that turns on and off at a little higher temp?

[Boydster]

Sounds like your fan is running off the battery. With no water circulating (engine off) the fan is only cooling radiator temps and not engine temps (I'm guessing your temp sensor is in the intake manifold). That's why it's running so long. I would use a key-on-hot power source. That way the fan shuts down with the key.

[NAZ]

Many OEM fan systems will run on after the engine shuts off. I don't like this configuration but if you see it as an advantage I suggest you install a time relay to limit run time after the engine shuts down. Del City (delcity.net) has a selection of them and they are easy to install and use. But if you elect to use a switched hot from the ignition switch you should also use a relay to operate the fan. Even if your fan is low enough current to be directly switched a relay will prevent the fan from feeding current back through your electrical system as it spools down.

[JETAV8R]

Sounds like your fan is running off the battery. With no water circulating (engine off) the fan is only cooling radiator temps and not engine temps (I'm guessing your temp sensor is in the intake manifold). That's why it's running so long. I would use a key-on-hot power source. That way the fan shuts down with the key.

Boyd,

You are correct. Just spoke to tech support at Ron Francis. He confirmed that the FF Ron Francis wiring harness is configured with battery power to the fan relay and not switched power. He also said they recommend part # AR-34 for engines running a 180 degree thermostat which has a 200 degree on and 185 degree off setting. He also explained how to change the relay to a switched power source, which is what I leaning towards.

[BadAsp427]

Had the same problem, got this one from HERE (https://www.walmart.com/ip/MATCC-200-To-185-200-ON-185-OFF-Degree-Electric-Engine-Cooling-Fan-Thermostat-Temperature-Switch-NPT-US/419697910?wmlspartner=wlpa&selectedSellerId=18528&adid=22222222227240493354&wl0=&wl1=g&wl2=c&wl3=286046621446&wl4=aud-481962823846:pla-483820976569&wl5=9010540&wl6=&wl7=&wl8=&wl9=pla&wl10=125216233&wl11=online&wl12=419697910&wl13=&veh=sem&gclid=CjwKCAiAmO3gBRBBEiwA8d0Q4iNEqxUN2YMp25YgfYM7 HeOOygTMnLWqbcCv2qSKhFPQP74x4v9bdRoC8u8QAvD_BwE) for $7.99 to fix that problem.

[FLPBFoot]

I chose to add a switch into the fan relay circuit with three settings. Auto, off and on. This way I can control the fan completely. I purchased a single pole double throw switch from FFR with on-off-on so it matched the other toggle switches on the dash.

[AC Bill]

So what, if it runs for awhile after shut-down? Won't hurt anything. Mine kicks on and off a few times, as there is some heat convection taking place, causing some coolant flow.

[scottiec]

Yeah mine runs for a while also. Although it’s kind of annoying, I might drill a couple of holes in the thermostate and see If that helps promote some more flow when it’s closed and car is off.

[Itchief]

I added a relay using a hot key source so that the fan would run only with the key on and the fan still uses the original fan wiring and fuse for power

Rick