High Temp Limit?

[Old Henry]

Just wondering if anyone has ever tested the cut-off temperature sender on the driver's side of the 59A-B engine to see what temperature it opens? I'm curious about what Ford felt was normal operating temperature range. I know the bottom end is the temperature the thermostats open. I just wonder what he designed the top end to be which would be the temperature that left "circuit breaker" opens. Anyone ever tested?

[V8 Bob]

Originally Posted by Old Henry

Just wondering if anyone has ever tested the cut-off temperature sender on the driver's side of the 59A-B engine to see what temperature it opens? I'm curious about what Ford felt was normal operating temperature range. I know the bottom end is the temperature the thermostats open. I just wonder what he designed the top end to be which would be the temperature that left "circuit breaker" opens. Anyone ever tested?

The left side 2 prong switch spec ranges from 212 -220 degrees F, depending on year and application, from the info I have on hand.

[Old Henry]

Originally Posted by V8 Bob

The left side 2 prong switch spec ranges from 212 -220 degrees F, depending on year and application, from the info I have on hand.

I would think 212 would be for a non-pressurized system as that is the boiling temperature of water at sea level and 220 would be with the 4 lb radiator cap on since that is the temperature the water would boil at sea level with that additional pressure.

Thanks for the info. That makes me a lot more comfortable running my engine at 200 in the hot summer, which it often is climbing mountains, since Ford thought that temperature was OK. I have the 4 lb. cap so looks like I'm good to 220. No worries.

[rotorwrench]

I think King Sealy stamped the top temp on the units unless you have a new unit not made by KS.

[G.M.]

Henry take the modern thermostats out in the summer. They have small flow openings resticting the coolant flow and you are finding exactly what I described happens with them in in hot weather. 200 is to high. G.M.

[Old Henry]

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Originally Posted by G.M.

Henry take the modern thermostats out in the summer. They have small flow openings resticting the coolant flow and you are finding exactly what I described happens with them in in hot weather. 200 is to high. G.M.

I used to take the thermostats out in the summer but it didn't make the engine any cooler than with them in except when going down hill when the engine got way below minimum operating temperature which was bad. So I leave them in all rear round to stabelize the temperature. Went to Pike's Peak last year and Death Valley last week without any problems.

[G.M.]

Ford never made 200 degree stats. Where is normal on the temperature gauge?? That should answer your question. G.M.

[Old Henry]

Originally Posted by G.M.

Ford never made 200 degree stats. Where is normal on the temperature gauge?? That should answer your question. G.M.

Thermostats only establish the minimum operating temperature. The port (left) side temperature sender that opens between 212 and 220 establishes what Ford considered the upper limit of acceptable operating temperature. Anything in between the minimum when the thermostat opens at 160 deg. and the maximum when the port sender unit opens at 212 deg. is acceptable operating temperature. I know most get a little nervous when the gauge gets up to the hot mark. That's why I've done this analysis to determine whether there is any reason to get nervous. If Ford set the port sender to not open until 212 deg which sends the gauge way to the right of the hot mark and my engine is only at 200 at the hot mark that's good enough for me so that I don't worry about any temperature lower than that.

BTW, I'm not sure what kind of gauge you have that has a "normal" indication. Mine just has marks at C for cold, 1/4, 1/2, 3/4, and H for hot. My thermostat doesn't even open until the gauge shows between 1/2 and 3/4 and others who have reported have said theirs is the same so normal for me is anything between there and the H mark. What are you calling "normal?" I'd like to see a picture of your gauge that shows a "normal" mark. Even modern temperature gauges, at least in all of my modern cars, show a very wide range of "normal" operating temperature from just above cold, when you get no heat out of the heater, and "too hot" when you better shut of the A/C and maybe even put on the heater in the summer or just plain stop to cool it down. In between is a fairly wide range of acceptable operating temperatures.