I have a 1939 Ford Standard (removable side panels) Coupe with 350 V8 and 350 transmission that has Vintage air conditioning and I'm running a 170 degree thermostat. In 2019 we moved from northern Ohio to the Central Florida. In the summertime, in Ohio, we could cruise on the hottest day with the air conditioning running full blast and the temperature would rarely exceed 220 degrees. In Florida last summer I had to remove the side panels to maintain 220 degrees or less and not run the air on the hottest days (wife pitched a huge fit). I had my cooling system checked out and it is OK. I was told I should drain my system and put in distilled water with a "water wetter" and I would be OK to run with the side panels installed and air conditioning on (will make wife happy). Recommendations please. Thank you in advance.
If it was fine before, then it could be as simple as a thermostat no opening. Sent from my iPhone using The H.A.M.B. mobile app
A couple of questions: have you checked the accuracy of your gauge; does it push water out the radiator overflow?
Automotive coolant staying at the desired temperature is a function of the coolant absorbing the engine heat, and the radiator dissipating that heat. Factors affecting this can be coolant moving too slow or fast, inadequate air flow through the radiator, not enough coolant volume to transfer heat, and ambient outside temperature. Is your radiator large enough? What type of fan are you running, Shroud? Engine timing? Air space around the engine? Based on what information was provided, I would look at airflow through the radiator first.
What radiator? Original? Walker? Electric or mechanical fan? Fan shroud? Does it cool down when you are moving, or does it run 220 all the time? Does it have inner fender panels? All of these variables can make a difference in a hot climate like Florida.
Never use distilled water unless you run anti-freeze with it....Pure water is very corrosive...Now soft water is okay...
Is your thermostat hi-flow? I always use distilled water since every market in the world has it with a 50/50 anti-freeze coolant. Personally I have never had good luck with water wetter as it jelled when I used it. Question about the car. Do you have a shroud and 5 blade fan or at least a 16” pull thru electric fan? Does ALL the air thru the grill forced to pass thru the radiator or does a lot go around usually over or under ina 39-40 Ford. A seal to the hood top and rad mount can be made and removable. For idling check and see if water is moving in the rad by looking inside with the cap off and the level 1” low. If it isn’t get a smaller water pump pulley. Last do you have a water overflow catch bottle and does it hold enough at 220* A 15 psi cap is worth 250* and if everything is good including the heater core which I’m guessing is part of your AC and will be...
The Traditional Hot Rods forum is probably not the right forum to post this in, maybe the mods can move it to the right place. You didn't say under what conditions the car get's hot, is it when idling for extended periods and at low speeds; or at highway speed? If during idling/low speeds it points toward a lack of air flow across the radiator. If at highway speeds it indicates a lack of cooling system capacity. These are rules of thumb, not hard and fast rules, but they do give some general direction for troubleshooting.
Gauges are Classic Instruments, installed about 5 years ago, they seem to be OK. I get a little water into the overflow tank when the temperature gauge reads 220-240. After 225 degrees, I shut off the A/C and the temperature holds. I only have this problem July/August when temperature/humidity are extremely high. Normal operating temperature this time of year (70-90 degrees) is about 170-180, but then I'm not running the A/C and the humidity is not so high.
Dan ask a few questions you haven't answered, it help's us in giving advice. Radiator, fan & shroud, a photo of the fan in relation to the radiator would help. I have owned several 39 & 40 Ford and have also dealt with running hot issues. HRP
If where you live in Florida has higher humidity than in Ohio, wouldn't that cause your cooling system to be less efficient? Basically the radiator and evaporator are simply heat exchangers. If the air surrounding them has more moisture (humidity), they cannot shed as much heat as they can in lower/no humidity. Anyone?
Does humidity reduce the heat transfer properties of metal to air? I don't know the answer to that, but I do question the claim. As far as I know, and I'm no expert on this, but heat transfer from a hotter surface to cooler depends on temperature differential, and the efficiency level of the material. More air flow across the radiator cools more effectively because the more air that flows across it, the greater the temperature differential remains. Humidity makes a difference to humans because we regulate our body temperature via evaporation of sweat from the skin surface, and humidity level of the air affects that. But a radiator does not rely on evaporation (although early IC engine powered agriculture equipment had open systems that simply ran the coolant over an open grid, and they did shed heat via evaporation). Any heat transfer experts or engineers that can offer more information on that?
You may need to put a hotter thermostat like a 180 degree in to slow the coolant flow through the rad- the 15 lb cap helps too. Has it ever boiled over or are you just worried it might? As long as the temp is controlled and it doesn’t boil over-good to go. Most modern cars ( If they have a temp gauge)don’t show a temp in degrees- just an operating range- there’s a reason for that
The problem with Florida is the ambient temperature is pretty high compared to Northern climates. Also, since the sun is out most of the time the surface temperature of the pavement is also much higher. So your radiator is sucking in hotter air thus it is harder to dissipate the engine coolant temperature. Fans, shrouds, clean cooling systems and making sure the hot air can get out of the engine compartment is a must. I never found the coolant additives that claimed to lower engines temps to be very effective.
We run a Hot Rod Shoppe in Central Florida, Hudson to be exact. Cooling issues and brake issues are tied for #1. Our tropical weather is unique compared to anywhere else since we are in the middle of the Gulf and the Atlantic. We find a high percentage of aftermarket gauges read incorrectly, the temperature sending units installed into the heads rather than the intake (different readings), etc. We see that most aftermarket electric fans are not up to the task, and in so many cases their is just no room to do much about it on finished cars. We just finished a ground up build '39 Ford a few months ago, w/350, A/C etc. with a Walker radiator,condensor,fan, Vintage front drive on the 350. The first thing I would check is all the engine and radiator temps with my Temp-Gun, and then go from there.
If the engine is not overflowing a lot of coolant then it seems unlikely that it is reaching 240. It may be worth a new thermostat and pressure cap on the rad. Same as recommended by Asphalt Angel. Another thing to look at is if all the shrouds are in place that holds in all the air between the grill & rad space so that all the air is directed through the radiator. There is plate that is available for the 40 ford that closes the triangle between the top of the grille and the rad so that air does not bypass up through the hood. This is the link to the Bob Drake one that also fits the "39s. https://bobdrake.com/collections/co...0-std-1940-41pu-air-deflector-stainless-steel . It would not be hard to make one with a piece of sheet metal. Here is the Van Pelt drawing that shows the side air shield 8105 where there should be a pair. http://www.vanpeltsales.com/FH_web/FH_images/FH_rad-grill-pics/Flathead_radtr39car.jpg https://bobdrake.com/collections/co...939-dlx-40-car-1940-41-pu-outer-grille-plates A shroud around the fan to improve its fan efficiency if there is none. That would be the low cost checks.
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