56 Temp Gauge not working

[captainbah]

Just bought my '56 about 2 months ago. The temp gauge was pegged at hot. The guy I bought it from said the temp sender needed to be replaced. I replace the temp sender and the gauge goes to cold when I turn on the ignition, but will not rise as the car warms up. I have run it for about 30 minutes and no movement.

I tried searching the threads in this forum, but did not see this specific issue. (Saw lots of threads about the engine over heating...which makes me want to fix this problem even more)

I did see the suggestion to add a digital temp gauge as a back up by placing a wire in the radiator hose at the clamp. Seems like a good idea.

Any suggestions to get the gauge working is appreciated. I do have a Chilton's manual and looked thru that but not sure I found the right page in the 1024 pages in the manual. thanks.

 

[Yadkin]

55s and earlier Fords were all 6 volt systems, from the battery and throughout. In '56 Ford went to 12 volt systems, and the gauges were designed for 12 volts as well. After '56 Ford started to use a 6 volt regulator to power the gauges: fuel level, coolant temperature and oil pressure.

So the '56 is unique that it has 12 volt gauges. The temperature gauge rests at H.

So your gauge works, but your sender does not. My guess is that your new sender is designed for the much more common 6 volt gauge. Macs sells senders specifically for the '56 year cars.

https://www.macsautoparts.com/ford_...er-temperature-sending-unit-12-volt-1956.html

 

[captainbah]

Yadkin,

Thanks for the information. First thing I did when I got home from work today is order a sending unit from MACS (12 V for 1956). When it arrives, I'll put it in and post.

The sending unit I put in the car came from eBay. It has the same part number as the one I ordered from MACS (B6C-10884) and says it is 12V, but I have been burned by eBay before with knock off parts. :mad When the one from MACS works, I'll send the other one back. The one from eBay only has one connection tab, where as the one from MACS has 2...not that the number of tabs makes a difference in performance...but it leads me to believe it may be a knockoff. The ebay seller is called Vintage Ford Parts. While I'm waiting for the MACS part, I'm going to pull the other one out and ohm it while it's in near boiling water.

Thanks for your help.

 

[Yadkin]

Macs has sold me plenty of inferior parts over the years, since so much stuff nowadays is made in China. But at least you have someone to answer the phone and return the part to.

 

[captainbah]

Yadkin,

The temp sender from MAC arrived Sat and I installed it this morning. I checked the part number to confirm it is a 12V sender.

The temp gauge still does not move off of C when the car is warmed up. I ran it for about 30 mins. The radiator warmed up to where is was uncomfortable to touch.

I put a temporary temp gauge in the car. Put the temp probe in the radiator where intake hose goes into the radiator and tightened down the clamp so it would not leak. The temp gauge is rated for 20F to 300F +/- 1F.

I ran the car for about 30 minutes yesterday and today..the temp settles out at about 150 to 155F. So I guess for now, I don't need to worry about the car over heating...although there was a lot of rust (?) in the coolant...probably need to flush the system.

Do you know what temp the coolant usually is when the gauge starts to register?...and if it should register at 150, do you have any other idea why the gauge does not seen to work?

thanks
bruce

 

[Yadkin]

Yadkin,

The temp sender from MAC arrived Sat and I installed it this morning. I checked the part number to confirm it is a 12V sender.

The temp gauge still does not move off of C when the car is warmed up. I ran it for about 30 mins. The radiator warmed up to where is was uncomfortable to touch.

I put a temporary temp gauge in the car. Put the temp probe in the radiator where intake hose goes into the radiator and tightened down the clamp so it would not leak. The temp gauge is rated for 20F to 300F +/- 1F.

I ran the car for about 30 minutes yesterday and today..the temp settles out at about 150 to 155F. So I guess for now, I don't need to worry about the car over heating...although there was a lot of rust (?) in the coolant...probably need to flush the system.

Do you know what temp the coolant usually is when the gauge starts to register?...and if it should register at 150, do you have any other idea why the gauge does not seen to work?

thanks
bruce

If the gauge rests at H then goes to C at key on then the gauge itself is working. Normal operating range is 180 to 210F or a little higher. From my experience with several Fords, not this particular year, the high end of the normal temperature range should be about the 1/2 way point on the gauge, and the low end 1/4 to slightly higher. I suspect that at 150 it is barely off C.

If the engine isn't getting over 150 then your thermostat is probably stuck open.

Since you are seeing a lot of rust I recommend flushing your system with either Blue Devil or similar radiator flush. You might actually want to do it twice, once at the ten minute interval and a second time, after one or two rinse cycles, for a much longer interval. The directions for this product are here: Radiator Flush | Directions

 

[captainbah]

Ran the car during the summer and the temp gauge came up to the middle. So it looks like the gauge is working fine. Thanks for your help.