Take a look at the following photo:

The T-fitting has been installed at Ford's original location for the heater hose that is routed back to the heater core on the firewall. Obviously, this area on the engine is the place to tap into to get the hottest coolant possible before it would go back to heat the core that heats the cabin. Since I am running an electric cooling fan on my radiator, I decided to tap in here as well so that the thermostatic switch could turn the fan on and off. Before I installed the original heater hoses and plumbing, the switch would work fine and ground correctly to actuate the relay, etc, when the coolant rose to the appropriate temperature. Once I installed this T-fitting however, the switch will only ground when the lever on the dash is in the HOT position, sending coolant through the hose. 

It seems to me that if I want to tap into this location, I can either have one or the other, but not both. Does anyone have any recommendations? I would imagine that although it's tight, I can put a T back at the head location where the temp sender is located. I would rather not do that because of how tight it is back there to manifold and to the linkage, but I was wondering if there were any other options.

Daniel Jessup

Loveland, Ohio

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

It would appear that the fan temperature sensing unit is too far above the intake manifold coolant cavity which means you’re in a spot where there is no water flow except when water is going to the heater core.  For the temperature sensing unit to be accurate, its ‘bulb’ needs to be closer to the actual engine coolant which means finding another hole behind the thermostat if wanting to retain the heater hose connection.  That does create a conundrum in that there’s not another factory location directly behind the thermostat for both the sending unit and your heater hose connection.  I run into a similar scenario with adding electronic fuel injection to Y engines which requires another hole for a temperature sending unit for the ECU.  For those engines, I drill and tap an additional hole (usually at an angle) right behind the thermostat.  That’s touchy as the manifold is not very thick for supporting additional pipe threads except at the original heater hose threaded hole area.

Lorena, Texas (South of Waco)

Even my blue thunder manifold is thin to either side of the thermostat, and on aluminum you have to be very careful not to run the tap in too far. I’ve also used the probes that go in the radiator, they just press between the fins and the one I had used a plastic cap installed on the probe in front of the radiator to ensure the cold air in front wasn’t affecting the reading. I was skeptical, but they’ve worked fine on two different cars. Might be an easier solution than pulling the manifold to drill and tap. This link is the base model, but still temperature adjustable. I had one that failed, well off warranty. But (since they’re local) I drove over to the plant to get a new one. They said they had a run with some bad electronics and replaced it for free.



https://www.summitracing.com/parts/flx-31147/overview/

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks for the replies, fellas. I never thought of a probe but it looks like that might be the answer.

I did get the car out in the dry, cold weather today and tested my transmission work. The third time was a charm I guess. Finally the end play was set and the clearances tight enough to keep second gear without popping out at cruise.

On to the next project.

Daniel Jessup

Loveland, Ohio

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Do you have power steering?  If not, maybe you can use that hole for the fan controller.



54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I have a temp sensor in the rear of the left cylinder head, could you tie into that?  Joe

Located in Harford County Maryland 

I tried using the oem temp sender to trigger a fan controller, no luck with the combo I had. Everyone has their own opinion on fans, but I like using the top of the radiator, and an adjustable unit. You really don’t want the fan on all the time (been there), just when needed. Typically it’s not needed except at low speeds. Mine is set up to read the top of the radiator with a 180 degree stat. Fan comes on at 190, goes off at 180. I guess it’s just as easy to turn it on at 190 at the manifold. There’s also a mechanical switch in the bottom of the radiator that comes on if the bottom of the radiator hits 200. That’s a back up in case the controller or upper sensor fails. Kind of belt and suspenders, or rain hat and umbrella.

My bird with a/c and the aluminum radiator and bypass restriction no longer overheats. With the a/c on stopped in traffic the fan comes on, runs 90 seconds, and shuts off. Back on in 90-120 seconds. On the rare 90+ degree day in Seattle.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

On my 56 Customline I installed a "Cooling Components" electric puller fan, but gave up on trying to find a suitable location for a fan controller sending unit. I ended up using a lighted toggle switch on the dash that I have to flip on and off as needed. I heard that there is a company (maybe Painless Wiring) that has a fan controller sending unit that threads into the radiator bottom tank drain, but I haven't researched that lately.
 

  Ron Lane,  Meridian, ID

I am adding a Mechanical Temperature Gauge. I had the Manifold drilled and tapped for fitting. Same Idea as Ted has done.. 

  

simple solution drilland tapthe therm housing rad side of stat. you only need the fan after stat opens