Overheating
 

I have been reading up on the flatheads and most people say that they will overheat very easily. I was wondering if that was true and what things could you do to prevent the overheating.

IF the block is clean of rust, scale and casting sand;

IF the radiator is clean;

IF the thermostats are in place and functioning properly;

IF the timing is set correctly;

IF the carburator is set correctly;

IF your crankcase is properly filled with oil;

Then your flathead will operate at normal temperature without overheating. I've driven them cross country running 24 hours straight with no problems.

The guys that talk about the heating problems with flatheads usually have problems with one of the above areas.

Flatty Overheating
 

I had a '53 F250 with the V8 flathead and it overheated at highway speeds. It appeared to be clean internally, observed when I replaced the thermostats and water pumps.......still overheated. Radiator cleaned.....still overheated. I went and found an "older" mechanic at the Ford dealership and he was happy to chat about flatheads. When I told him what series truck it was in he said that with the 4.86:1 gearing it was moving the water through the system too fast to cool it. "Cut a piece of brass stock to the size of the thermostat and drill a 1/2" or 3/4" hole in the middle", he said. "Replace the thermostat with this". Guess what, cool as a cucumber on the road then. Sometimes experience just can't be beat!

Also those old engines only need a 160 degree thermostat and the shroud on radiator should be in place.

flathead overheating
 

My Dad raced flatheads in the 50's and when I decided to build one, he told me to take 2 pennies and drive them in the center water ports in block. It worked for us.

I've got a 52 F3 with a 4.86 gear, but I don't drive it on the highway. It doesn't seem to run hot, but it blows coolant out the top of the radiator. I am planning to install a recovery tank, but I would like to run it cooler too. NCRanchero: Where does this brass piece go in relation to the thermostat, and how thick is it? ajr711: Give me some more detail on where to put the pennies.

What this "seasoned" Ford mechanic told me to do was replace the thermostat with this piece. Dimensions, the same O.D. and thickness as the thermostat with a 1/2" or 3/4" hoke drilled in it.( Just a BIG washer with a little hole).

The blocks on these old flatmotors are usually have a lot of "Casting Sand" way down in the water jackets. Any body that has done any rebuilding will tell you to make sure that the block has been cleaned out.
And make sure its set as MTFlat has stated.

I mounted a recovery tank on my F3 and got it plumbed to the overflow tube, which was hidden from sight and access. I installed the Stant cap that is designed to work with recovery tanks (allows coolant to get sucked back into the radiator).

I topped off the radiator and fired her up. I drove it a half mile from where I store it to home. Because it was loosing coolant and the dash gauge indicated high temps, I wanted to measure the engine temp. I left it idling and measured the surface temperature of each head using an infrared non-contact thermometer at 10, 15, 20, 25 and 30 minutes. The ambient temp was 80 F. The driver's side temp was consistently and 160 F at each measurement and the passenger's side was 165 F. I interpreted these temps as good news.

At the 30 minutes, coolant started to drip off the frame onto the ground at a fairly quick rate. I cut the engine and started to look for the source. I check the recovery tank and found it to be dry. I thought that if my connection to the overflow tube was bad, some coolant would still reach the recovery tank. I ragged it all off and it stopped flowing. I fired it back up after having it off for about 15 minutes, and ran it for 20 more minutes. It would not leak again. I cut it off and searched some more. I found that the clamp on one of the lower radiator hoses (the one near the exit of the overflow tube) had some greenish white crust on it. I loosened the clamp to the point that it leaked, and the coolant dripped off the same points on the frame that it had previously. So, I tightened the clamp, and so far no more leaking.

I guess I took the long way to tightening a hose clamp.

If you do alot of highway driving, you can cut off every other impeller blade on each water pump and it will not heat up during highway driving. Be careful around town, because extended idleing is sometimes a problem in warm weather.

I found that the coolant was, at times, leaking out of a top tank seam. I got the radiator recored. I paid $425 for the work; about twice what I expected to pay. Ouch! I put it back in, and no leaks and it runs cool.

I have a 51 226 6 cylinder and it has never gone above 170 with a 160 thermostat. It just runs and runs, wish I could say such nice things about that non-syncro 4 speed. They say the 6 was Henry's secret, I understand now what they meant, It's one sweet little engine.

if your still running the stock heat gage when they are all the way over on hot they are at 210 d thats not that bad alot of new cars run at 210

2006 6lt disel overheating with white smoke from exhaust

the pennies were placed on top of the block under the heat risers on the intake manifold. This will not cure an overheating problem just keep the intake cooler which is good for racing. I have pulled as much as 30,000lbs with my truck and have not had any overheating problems. I did find that my truck runs better loaded or unloaded with 180 thermostats in it and it runs cooler when loaded with the 180s. Remember heat will help atomize the fuel and make your engine run more efficiently. make sure your rad cap is not releiving pressure prematurely. As long as you are running under 230 degrees your engine will be ok. 180-200 is ideal.