Erratic Water Temps in '56 Y block

[Bonniewwyn]

Car is a T Bird. When we bought this car temp gauge read hot after only driving a few miles, Stopped at a friends shop and they have a heat gun...motor was reading 180 but gauge was pegged. Headed home and temp dropped to normal for a while but would go to HOT at every traffic light. I figured it must be sender. Let car sit all night and started out at cold but soon went to hot again. Bought a new sender from NPD and installed today. Now it reads HOT and gauge doesn;t move at all. Original sender had 2 ears on top that took push on wire connectors. New sender has 2 ears with screw holes. There was only one wire on the sender when I pulled it and I don't see any loose wires around that part of the motor. What am I doing wrong ??

[dmsfrr]

The new sender may be the wrong part. Screw terminals are not correct, photos below.
A '56 Temp sender (and gauge) are 'one year only' parts and don't match anything else.
They look like a '55 sender but are made for 12 volts. Part number 10884-B, at this link...
https://www.classictbird.com/Temp-Se...ctinfo/10884B/

Having one wire on the sender from the gauge is correct. The double terminal is a left-over design from some Flathead engines that had two temp sensors. See this link...

https://www.google.com/search?q=ford...OCESr8M:&vet=1

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[Bonniewwyn]

Thanks. Iordered from NPD as they re just a day away. I'll pull the unit and try to return for credit. Try Casco one next !

[dmsfrr]

Also, double check the insulation on the sender wire to the gauge. If it's worn thru and grounding out anywhere that can make the gauge peg out.

[JimNNN]

Have you ever thought about a decent quality mechanical gauge? Originality is nice, but if the engine is original, it would be nice to know precisely what the water temperature is so that the original engine doesn't get damaged. I kept the substandard factory electrical gauge for far too long. Before installing, you can put the sensor of a mechanical gauge in a pot of water that's just coming to a boil to find out exactly how accurate it is. You can also find out how exactly how much the engine is heating up on summer days after you shut the engine off. Things you can't easily discern with the original gauge. For years I thought the Y block in my '54 wagon was running somewhat hot. After I put in the mechanical gauge in I realized that it was actually running a bit cool and needed a new thermostat that closed better.

[Sid]

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I know 56 Ford cars were 12 volt gauges. I am not sure that it applies to the sender but it may affect it. 56 was the only year for many years that was 12 volt 57 to somewhere in the late 70's or even early 80's were all 6 volt gauges that had a resistor to cut their voltage. It may be that that 56 sender is to be 56 only. Just last year I had a 55 Ford here with a replacement sender and would read hot after just a few minutes of driving. I replaced the sender with a used one from a 55 Ford and all is good now. You may want to check toe resistance of your sender and I'm sure someone here may know what the resistance should be. I may also have a 56 Ford sender I can check also.

[KULTULZ]

Originally Posted by JimNNN

Have you ever thought about a decent quality mechanical gauge? Originality is nice, but if the engine is original, it would be nice to know precisely what the water temperature is so that the original engine doesn't get damaged. I kept the substandard factory electrical gauge for far too long.

Before installing, you can put the sensor of a mechanical gauge in a pot of water that's just coming to a boil to find out exactly how accurate it is. You can also find out how exactly how much the engine is heating up on summer days after you shut the engine off.

Good idea here. Heat soak amount.

The FYB had the coolant temp sensor located in the wrong spot as it sees only coolant temp coming out of only one bank of cylinder barrels. It does not see the temp gained while crossing the adjoining exhaust valves on cyl(s) #6/7 left bank and #2/3 on the right bank which are hot because of another design flaw.

A mechanical gauge will be much more accurate. The sensor should be located in the front coolant cross-over at the front of the intake manifold.

If you have a BIRD, you need to be aware of other cooling system design flaw(s).

[dmsfrr]

Originally Posted by Bonniewwyn

Car is a T Bird. When we bought this car temp gauge read hot after only driving a few miles, Stopped at a friends shop and they have a heat gun...motor was reading 180 but gauge was pegged. ...

Originally Posted by KULTULZ

... If you have a BIRD, you need to be aware of other cooling system design flaw(s).

If the actual running Temp is pretty normal you may not need to change anything else once the gauge is working well.

Here are a few things that can be worked on or improved if the engine is running too hot. See these links...

In addition to the several overheating causes mentioned, note the 3 photos at the bottom of the page at this first link.
https://www.ctci.org/gilsgarage/1955...d-overheating/

https://www.ctci.org/cracked-exhaust-manifold/

https://thunderbird.us/

https://www.ctci.org/1957-thermostat/

https://www.classictbird.com/Water-P...ctinfo/8501HO/

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[KULTULZ]

Removal of the extension does not effect the operation of the heater control valve.

Just so you know -

That extension tube purpose is to draw coolant from the bottom of the intake coolant crossover. It allows for less air bubble pickup which may air-lock the heater core.

There is an aftermarket high flow WP impeller/shaft that will allow the retention of the numbers correct WP casting if it is numbers correct car.

Think twice before removing the heat riser valve depending on where you live.

[miker98038]

To further complicate matters, those are King Seeley gauges, and don't work like most of us are used to. A fellow named bergmanj put up a series of articles on how to adjust them over on yblocksforever a few years back. I managed to find part of it. They are matched sets, and I believe the 12v 56 only is the same as the earlier and later 6 volt (or 12 to 6 volt drop) all adjust the same. Either way the article is worth reading, and you'll find more references for other makes that used these gauges. Might be of some help once you know you have all the right components installed. My 56, 12 volt gauges in my 55 converted to 12 bird work well within tolerances. The temp guage is accurate at normal temp, and it's too hot when it pegs. The fuel gauge shows full for a time, but at 1/4 tank you've got 1/4 left. That's the two important places for me.

The jpeg attachment shows some detail worth looking at. Bottom of first page.

http://forums.y-blocksforever.com/Topic22135-1.aspx