OK you flat hed gurus,im new to the flathed scene,i have a 53 239,that had an over heating problm,i flushed rad and coolingsystem and installed 160 degree thermostats,my temp gauge reads just past half way to 3/4 -so far hasnt gone all the way to hot,truck is not "bulbling over -or seem to be over heating,maybe afaulty temp sender?? whre should gauge read??

 

It could read anywhere. The most important thing is to make sure the system is clean and that your radiator has the fan shroud on it!

If you really want to know what's going on, by the $10 water temp gauge and install it in one of the extra ports. See what it says and then take it out if you don't like it.

 

Welcome to flathead insanity - you'll get hooked if you're not careful.

Basically what 2speed said. The stock gauges are notoriously innacurate. They give you a general indication of where your temp is relative to your truck. Mine runs just above 3/4 normally and bumps about halfway between 3/4 and H when I push it hard or climb a mountain pass here.

You should run a 180 T-stat. 160 won't let the engine get warm enough to evaporate the contaminants in the oil and causes sludge buildup and increased wear in the engine.

Keep the coolant level about 2" below the top of the rad neck - it needs some room to expand. It'll puke the extra out the overflow tube until it reaches its own point of equilibrium.

If I read your note correctly, you don't have coolant loss or any other signs of overheating. Did you assume it was too hot just because of the gauge reading? If that's the case, put it back together and drive it! If the gauge ever pegs on the hot side, stop immediately and find out why. Otherwise I doubt it is too hot.

If you have access to an infrared temp sensor check the head, hoses and rad top tank for actual temps. Then you'll have a better picture of whats going on.

Hope some of this rambling helps. If not, ask away and we'll keep trying.

 

YES VERY HELP FULL I AM RUNNING A FAN SHROUD! AND BEFOR I FLUSHED THE COOLING SYSTEM AND REPLACED THE THERMOSTATS MY TRUCK WOULD OVER HEAT AND COOLANT WOUD BUBLE OVER,SO FAR HAVENT HAD ANY OF THAT SOUNDS LIKE YOUR TEMP GAUGE READS LIKE MINE!

 

If you do install a mechanical temp gauge be sure to install two, one on each side as they are actually two different cooling systems with one radiator.

 

I disagree with the need for two temp gauges, unless you are trying to isolate a problem to one side of the engine, like pump or thermostat. An easier way to isolate to one side is the hand held IR thermometer, that mtflat recommended. Borrow one, or for about $50, buy one. Warmed-up, the surface of my heads are about 175 degrees. The stock flathead has two senders, but one is actually a switch. When the switch gets hot, it moves from open to closed and the gauge goes full hot. The other one has a variable resistor that senses the temperature. To test the gauge (this works for FUEL and OIL too), take the gauge out of the circuit and apply 1.5 Volts DC across the posts. The needle should move to the center of the range within about 20 seconds. If it is close to center, you have calibrated how to read that gauge. If it is way off or motionless, replace it.

 

I was refering to the use of mechanical gauges to constantly moniter the engine temp, not calibrate the factory gauge.

 

Because the coolant mixes in the radiator from both sides of the engine, I think that one properly functioning gauge is sufficient to constantly monitor the engine temperature.

 

What happens if the left side thermostat sticks and your gauge is in the right side?

 

Your whole engine gets hot.

 

Im not sure I support your reasoning. If there are two water pumps and no crossover in the intake and one side thermostat sticks closed how do both banks run hot?

 

Flathead blocks are small and cast iron is a good conductor of heat. The whole block will warm-up. Pistons on both banks are connected to the same crankshaft; the whole engine shares a single oil supply. Everything is in close proximity; none of the materials are good thermal insulators.

 

I guess that makes sense, except one side is having heat transferred to cooler water that is going to vary the temp between the two banks. I understand that the heat will travel from a hot place to a cooler place but that takes time. And alot can happen in that time. I will not chance it with my motor. I'll stick with the extra gauge.

 

Both arguements make good sense. I installed two gauges for my 59A flatmotor and I feel good about the added security in knowing that if a water pump goes the trip, I have a good chance of finding it sooner than later and will know what side it is. Steve

 

I agree, Its not like you can go to any junkyard and find a good deal on a flathead these days!