Antifreeze Thoughts

[Oldav8tor]

I had a talk with a very knowledgeable Model T'er today on the subject of overheating. He brought up and interesting concept. Like me, he runs a 50/50 antifreeze/water mix in his car. He went on to say that his car started overheating where it hadn't before. Investigating his problem he came to the conclusion that the water was boiling off leaving the antifreeze behind and as we all know, antifreeze alone does not cool as well as water. When he checked the specific gravity of the mix in the car it seemed to be more concentrated than 50/50. He was able to correct the overheating problem by topping off with water, not mix.

Thinking it over I came to the conclusion that his explanation may have some merit. Water boils at 212°F while a 50/50 mix boils at 223°F. The Model T has an unpressurized cooling system with a vent tube open to the outside. A 15 psi pressurized system would raise the boiling point to 268°F and being sealed, would not normally allow vapor to escape. Vapor can escape from the Model T's cooing system so why wouldn't water boil off from the mix or escape by evaporation, thus increasing the concentration of the ethylene glycol? We're talking simple distillation here unless I'm missing something. Any thoughts?

[TXGOAT2]

I believe you are correct. A periodic check of the coolant's specific gravity would be a sensible precaution, and would indicate whether to add water or anti-freeze if the coolant level was low and no leak was evident. A 1 quart vented coolant overflow bottle with a pint of coolant in it would probably capture most escaping water vapor along with normal expansion displacement. That would minimize water loss and allow the radiator upper tank to remain brim full, as long as the cap was air tight. I've often removed radiator caps to check coolant level after a vehicle had sat overnight and noticed clear water condensate on the underside of the cap. That strongly suggests that water can escape from typical coolant solutions as vapor.

[Allan]

Tim, your thoughts depend on the antifreeze not having water in it. If there is water already mixed in the antifreeze and you add 50% more, then that purged by the system will come from both constituents. Your car will be re-concentrating the antifreeze,.
I am fortunate to live in a climate where antifreeze is not necessary. I run a coolant mix in alloy head engines and some soluble oil in iron heads, purely as a corrosion inhibitor.

Allan from down under.

[browning]

My cars are “fair weather” creatures and are never in an unseated space and never driven in the cold. I maintain the antifreeze levels only to prevent corrosion. I wonder what concentration of antifreeze would provide maximum cooling and provide the necessary rust protection.

[su8pack1]

This past June I put Evans Waterless Coolant in my Model A and so far so good. I'm thinking I'll do the same with my 25 Roadster. It boils at 375°F.

[Scott_Conger]

Dan

you need to do some more research before you pin your hopes on Evans. Do you understand the difference between heat transfer and boiling point? Do you know the meaning of Specific Heat and how it differs from boiling point? Do you understand how thermosyphoning works? Do you understand the difference between having a pump and simply thermosyphoning? Do you realize that Evans coolant does not change density with temperature change? Are you aware that the manufacturer specifically advises to NOT use it in an open thermosyphon system?

Now, granted, no one needs to know any of this stuff to add a 50/50 mix of coolant into a radiator, but one DOES need to know a little bit about thermodynamics (or heed the manufacturer's advice) when contemplating switching to Evans coolant in a T.

If your car is boiling over, you need a new radiator, not a coolant which cools even less (despite having a very high boiling point). The idea is to keep things cool, not stop boiling of a decrepit system.

I offer this advice not to be a smart-alec, but to ensure that you are considering the vast difference between a cooling system that uses a pump and one which relies on thermosyphoning. They are entirely two different things.

[Moxie26]

Just after we had the engine rebuilt in 2002, Evans coolant has been used. Hose to metal connections had to be sealed no matter what type of clamp was used. That has been the only problem and it's been leakless ever since. The Evans waterless coolant was purchased through the shop here in New Jersey that has a great interest in saving and rebuilding Tucker automobiles.

[TXGOAT2]

A vented, non-pressurized system on a car using alcohol based anti-freeze will tend to lose alcohol via evaporation, especially when operated in warmer weather periods. The same system using glycol-based anti-freeze would tend to lose water under the same conditions. In both cases, checking the specific gravity of the coolant regularly would be advisable. Coolant volume in the T system can be reduced via leaks of any sort, evaporation, or by "burping" of coolant out the overflow under certain conditions. It's advisable to check the specific gravity of the coolant often, as well as the coolant level.

[TXGOAT2]

I don't have a Tucker on hand, but I believe the Tucker employs a pressurized cooling sytem. The Model T Ford does not.

[Mark Gregush]

My thoughts on anti-freeze: 50/50 mix year-round, aint going to change what I have been doing for about as long as I have owned any cars, and that has been a good while now.

[Scott_Conger]

From the Evan's Website:

Model T Application
Can this product be used on a model T with a gravity circulation?

Mike:
Ford Model T's without a pump rely on the boiling of the water to circulate the hot coolant. This type of cooling system is known as a thermosyphon system (gravity circulation) Evans Waterless Coolant will run hotter than the water system due to the higher boiling point and the lack of vapor that moves the coolant when it boils. We normally do not suggest using Evans Waterless Coolant in this application, although we have had success in the past. This success depends A LOT on the condition of the radiator and the actual temperature range.

Bottom line: if you want your "T" to run hotter than with pure water, hotter than with coolant and your only concern is to "not boil over" then Evan's is the product for you...and best run with a brand new radiator.

While the Evan's "Answer Guy" is a bit muddled in his description of Thermosyphon, his lack of specific accuracy in it's description in no way affects the reality of the Evan's product and how it reacts to a thermosyphon system. I see no upside for this product in a T, and the manufacturer's conclusion is essentially the same. Yes, they have had some success with it, but you will notice that they do NOT recommend it (and where else in life have you seen a manufacturer who would NOT recommend using their product for the very purpose it was designed for...cooling?)

[Norman Kling]

Since I live in southern California, it rarely freezes here. I use the 50-50 for it's higher boiling point and also the rust inhibitor. It has enough anti in it for the rare occasion of freezing here. Before the last time I replaced the head gasket and found out why it used to blow from time to time, it hasn't boiled nor lost coolant. That was about July. We took one tour in very hot weather with much uphill. It did not get above the center of the circle in the motometer, so the problem seems to be fixed. Anyway, I usually fill with 50-50 (the green stuff) from Walmart and then if I need to add later, I use purified water. I have had no problems.
Norm

[Moxie26]

Well at this time, let me be the "Evans answer guy". ........ With a new brass works radiator from 20 years ago and a rebuilt engine from 20 years ago, a thermometer style radiator cap to monitor engine temperature.. I have had no problems with excessive temperature or evaporation of coolant.. like a previously mentioned the only problem I had, and solved, was using sealant on the hose / metal connections to stop coolant loss.... Plus, I have not seen any corrosion problems in coolant passages, during the time the system was drained and resealed. I would say that's pretty good for a lifetime coolant that has served for 20 years on the standard Ford thermosyphon. . And no water pump!

[TRDxB2]

I guess I don't see the advantage in using a coolant or mix that would raise the boiling point over 250°F. It is my understanding that the desired operating temperature of the engine is between 180°F & 220°F. Since water boils over at 212°F it may be necessary to use a coolant depending on where one lives, radiator efficiency (and okay using a water pump). But raising the boiling point of the coolant does not cause the coolant or engine to run cooler but hotter before boil over is noticed. I think that seeing a steaming engine is a good sign to pull over. I assume that high temperatures aren't good for any engine.

If the cars cooling system is in order and keeps the coolant in the desired range, 180°F - 220°F, having any coolant with a high boiling point above 250°F seems unnecessary.

[su8pack1]

Scott, thanks for the thought. I haven'y done anything yet with the T and the Evans Coolant. I'll use the 50/50 first to see how it runs and will most likely stay as per your, and others comments on it. As for my A with a water pump, no problems since I started using it.

[TXGOAT2]

The Model T thermosyphon cooling system does not depend on boiling to circulate water/coolant. Some early cooling systems do depend on boiling, but the Model T does not. Boiling in a Model T is to be avoided for several good reasons. The Model T system depends on the change in density of the water/coolant due to expansion from heat from the engine. Gravity is what actually moves the coolant. The system is designed and laid out specifically to take maximum advantage of the thermosyphon effect. The system works very well with a 50/50 mix of glycol-base antifreeze and clean water. Any substance that does not expand when heated is not suited for use in a Model T cooling system unless a pump is added.

[Oldav8tor]

The reason I started this thread was a conversation with Tom Wright, a knowledgeable mid-Michigan Model T'er. For me it was a "dope slap" moment as his comments made a lot of sense and explained some observations I'd made that I really hadn't given the attention to that I should have. The open cooling system of a Model T does not operate under the same principles as a modern car and you need to understand what is going on.

In 2022 I drove my '17 Touring 2571 miles. Many of those miles were on 90° days but my T never overheated. A couple of times during the year I had to add a little coolant, thinking it simply went out the overflow. I added more 50/50 mix never realizing that the bulk of the lost coolant was probably water vapor and my adding of 50/50 was actually increasing the concentration of ethylene glycol.

I think in the future I will "top off" with distilled water while at the same time monitoring the specific gravity of the coolant to try to keep it near 50/50. Michigan winters can get pretty cold so I have to be sure to maintain a mixture that won't freeze and damage my engine or radiator.

One thing about Model T's....you never stop learning.

[Scott_Conger]

Tim

it's well that you brought this subject up. As the US is headed into a pretty widespread deep-freeze, it is a timely topic. Coolant/antifreeze is an odd thing...as you increase concentration of anti-freeze as some of us have to consider in -30F temps, you are actually losing your cooling capacity which it sounds like you may have encountered. Your idea of adding distilled water is a sound one, but as you know in MI, you must also watch that you don't drop the concentration too precipitously either, which I know you are aware of.

In any event, today is a great day for everyone to test your concentration of anti-freeze and watch the weather map closely.

Stay warm!

[Kerry]

My Father loved antifreeze, made him a very wealthy man, the stuff is corrosive to solder. Even new cars from England sold in Australia needed radiators replaced before leaving the show room.

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[TXGOAT2]

Soldered radiators can suffer from "solder bloom" if the coolant is neglected. This appears as a white crust around the solder joint between the upper tank tubes and the header plate. Aerated coolant or a leaking headgasket sitaution would probably aggravate the tendency. I believe that using anti-freeze as directed prevents the problem.

[Norman Kling]

When the cooling system is in good condition and clean, the thermo syphon system works very well. If you do use a water pump, you should also include a thermostat. The reason is that the water pump keeps the coolant circulating even when the engine is cold and without a thermostat, it will delay the warm up. In fact on a cold day it can even prevent warm up. The first T I bought had a water pump without any thermostat when I bought it. In the winter, we drove up into the mountains to about 5,000' where there was snow on the ground. Even though we had been driving uphill for about 30 miles, when we got to a rest stop, we all stopped for a break and I noticed others were standing in front of their radiators to keep warm. Mine was still cold! I realize it doesn't get as cold here in California as in most other states, but it still gets cold enough to have snow in the high mountains here. With thermo syphon, a system in good condition will not overheat even in hot weather.
Norm