1952-59 Ford Cooling problems?

It's almost summer and already the rising daytime temperatures are beginning to pose cooling problems for our custom rides.

It's clear from the posts I've read on the subject that there is a lot of confusion about how to get our cars to run cool. Most of the suggestions given, while being well-intentioned, do not even consider what the true causes of the problem might be.

Perhaps I can help. But before we even consider the cure, let's isolate the cause.

Overheating at road speed is different from overheating at low speed.

If the car cools adequately at low speed, but overheats at driving speed, chances are the flow of air through the radiator is restricted.

If the car cools adequately at road speed, but overheats at low speed, chances are the coolant capacity (radiator size) is too small and/or the fan system (unaided by vehicle movement) does not move enough air through the radiator core.

Your first step is to isolate whether your overheating problem is a road speed problem or a low speed problem. Once you've done that, you're ready to look for a cure.

Road speed overheating:

A number of things can cause a restriction in the flow of air through the radiator core at road speed.

These include, but are not limited to, a grille opening that is too small, openings in the core support which allow air to flow around the radiator core instead of through it and an over-crowded engine compartment which does not allow enough openings for the heated air to exit.

The two most common causes, however, are air conditioning condensers (and to a lesser extent ****** coolers) mounted too close to the radiator core, and electric fan shrouds(!) in either the "pusher" or "puller" positions.

Try this: temporarily remove all the obstructions (or seal the holes) on both sides of the radiator and see if the road speed cooling problem goes away. If it does, make the necessary changes on a permanent basis.

Low speed overheating:

If the radiator you are now using is at least as large as the one in the car the engine came from you probably have enough coolant capacity. If the radiator design is modern as well, you can probably discount the radiator as being the cause of your overheating problem. (You must add radiator capacity for hopped-up engines as they produce more heat than stock engines)

Engine-driven fans turn slowly at low road speeds and turn fast at higher road speeds. This is the opposet of what is needed, but was the best available technology at the time.

Electric fans turn at a constant speed regardless of the road speed.

If you are relying on an engine-driven fan, you must make it efficient at low road speeds by maximizing its ability to pull air through the radiator core unaided by road speed.

There are two ways of doing this: increase the number, area and pitch of the fan blades, and/or increase the efficiency of the low-pressure area (air pulling ability) produced by the fan by adding a well-designed fan shroud.

The popularity of electric fans is the result of their ability to produce high rpms at low road speeds, a situation impossible to achieve with an engine-driven fan. Their on/off operation can also be regulated by the coolant temperature, another feature not available with an engine-driven fan.

The downside of electric fans is that they are advertized as cure-alls. They are not.

Electric fans seldom if ever cure road speed overheating problems and may even make them worse.

Adding an electric fan may marginally improve cooling under certain limited conditions, but do not encourage the user to search for and correct contributing problems such as blocked air flow, mis-directed air flow, insufficient coolant capacity and/or an inefficient engine-driven fan setup.

And on a personal note, from a traditional hot rodder / custom car guy's perspective, electric fans have yet one more downside: They look like *** on an otherwise clean, well-built car.

Hopefully this short tutorial has been helpful.

 

Hot Rod Magazine did a great article on this subject about two years ago and covered everything.

The one subject they covered was the speed of the coolant through the radiator.... Often we pick performance pumps that flows so too much coolant through the core at a speed that the radiator does not have a chance to soak up the heat to cool it, so we tend to change the thermostat to a lower opening temperature making the situation worse. The coolant has to be in the engine to saturate the heat away and distribute it to the radiator for transfer.
I have the luxury of having one of my best friends that owns a radiator shop.... I have learned a lot from him in cooling an engine. He suggests that one needs to just sit and consider what the function of the cooling system does, he says it's simple if you understand the function. It's about air flow and heat transfer.
One more thing.... an engine's combustion effiency is determined by the combustion temperature., Engine heat determines that temperature. Many of us want our engines to run in the 160 or so range.... that's too low! Our engines need to run in the 185 to 190 range to be able to tune the carb and burn all the fuel in the combustion chambers. Late model engines typically run in the 210 range for emmissions and effiency. I set all my engines to run at 185 at all engine speeds. I found out that my Autometer guage reads 180 degrees and the motor is actually at 185 degrees taken at the same place on the motor. You can get different readings by where the sending unit is located. If it is in the head it will read hotter than if it were in the intake manifold next to the thermostat.
As Eric mentioned, so many things to consider including engine tuning, lean running carb setup, distributor timing, blocked water p***ages, trapped air in the engine, and tight engine clearances all can contribute to engine heat.
Many theories on this..... it's rather simple.

 

Thanks, Geno! Your observations are spot-on.

Geno's Law: First, be sure your overheating problem is cooling system related.

There's no use throwing money into cooling system parts if the source of the problem is a mis-tuned engine or a poorly selected engine component.

Perhaps a second Geno's Law would also be appropriate, since it is closely related to the first: Be sure your cooling system is in good operating condition.

Seems simple enough, but have you flushed your system lately? Replaced thermostat, radiator cap and coolant with correct, high quality service parts? Have you checked for soft, spongy hoses and slipping belts?

How long has it been since you pressure washed and blew out the radiator core itself?

Geno is absolutely right: there are a lot of factors which affect proper cooling of a modified car, and missing any one of them can ruin your day.

Thanks, Geno!

 

very well written here . i have to say this . those little 7 blade aluminum aftermarket fans with the skinny blade that have no curve to them just the bent angle . those things cause ooverheating at highway speeds . they straighten out and act like a wall behind the radiator and block air from going through the radiator . the original style curved fans work the best as far as engine driven . also now with the serp. belts most of the serp belt waterpumps turn backwards . you need to be aware of this when replacing a water pump . dont get the wrong one . also if your running a fan clutch. and your clutch locks up to turn solind with no slipage . that too will cause overheating.