thermostats, yes or no?

[st63]

Ok, so I'm having an interesting debate with my friend and mentor, an older gentleman who for the last 40 years has made his living restoring and maintaining vintage cars.  When I repaired my water pump recently, he suggested I leave out the thermostat entirely when re-installing the upper radiator hose.   I questioned that...because I figure the original engineers put it there for a variety of reasons besides just letting the car warm up properly on cold mornings...but I went ahead and tried it.  I refilled the radiator with my usual summer mixture of 1 gallon anti freeze, 1 pint of redline water wetter and topped off by 2 gallons or so of distilled water.  I've driven it on the local highways on some pretty hot days, and so far I haven't noticed any major differences in temperature.  I hear from some folks who advocate running without a thermostat, claiming the faster water flow will cool better.....others say that  flow needs to be restricted somewhat(by the thermostat)  to allow the coolant to stay in the radiator long enough to cool properly  before re-entering the water jackets.  I tend to side with the latter, but I'm no engineer, so I'm curious to know what others think about this.....

By the way, I'm running the stock 201 flat head 6 with stock water pump and radiator.

[1941Rick]

You are correct, and yourfriend who explained the purpose of the thermostat is correct. As for the older fella, who you call a mentor.......look for a new mentor.

A lot of people who do not fully understand how a cooling system works will agree with your mentor. Coolant must remain in the radiator long enough to cool only around 10f before entering the engine. In high horse power engines, if you run without a thermostat the coolant just keeps getting hotter and hotter.

[st63]

That makes the most sense to me...i would think faster water flow only helps if it's fresh, cooler water, but since it's a closed system the idea of faster flow is counter productive.  I'll wind up re-installing the thermostat....

[Plymouthy Adams]

not only is it a device that will bring your car coolant to the proper temp it is also a control flow valve that ensure that you are nether circulating your coolant too fast or too slow...too fast you will not absorb the heat into the coolant from the engine block..too slow and you will not exchange this heat properly across the radiator...even old guys who have messed with these cars for years were misinformed long ago and were never corrected over time...I would not dismiss him entirely..only question a few of the things he may say....9 out of 10 he may well be dead on the money...

[pflaming]

Question: If one is not using antifreeze, then is the benefit of a themometer present?

[Don Coatney]

Question: If one is not using antifreeze, then is the benefit of a themometer present?

I don't think a thermometer is required if you substitute blinker fluid for antisqueeze.

[pflaming]

I do not like this keyboard so will rephrase or restate my question; if water only is in the radiator, is there still a benefit from or a need for a thermostat? In my recollection I think Dad removed the thermostats in the summer but I may be wrong about that. I know we ran water only in our tractors and grain harvester engines.

[TodFitch]

I do not like this keyboard so will rephrase or restate my question; if water only is in the radiator, is there still a benefit from or a need for a thermostat? In my recollection I think Dad removed the thermostats in the summer but I may be wrong about that. I know we ran water only in our tractors and grain harvester engines.

 

The "instruction book" for my '33 Plymouth makes no mention of running without a thermostat.

 

 

. . . Very hard or lime water should not be used in the system. Because of the scale forming chemicals in contains, its use will cause scale to form on the walls inside of the radiator and cylinder water jackets, which, in a short time, will restrict circulation of water. . .

 

As an added protection to prevent scale and rust forming in the cooling system, "Rust Resistor" should be added to soften the water and prevent the accumulation of scale and rust. . .

 

. . . At the first indication of freezing weather, the cooling system should be filled with a good non-freezing solution. Denatured Alcohol, Clycerine, or Ethylene Glycol and water in proper proportions, make very good solutions, but care should be taken to prevent spilling alcohol on the lacquer finish of the car. . .  The solutions should be tested about once a week to make certain that they will not freeze in the prevailing temperatures. Do not confuse Full Strength Glycerine with Radiator Glycerine, which is a 60-40 solution. . .

 

One reason for older cars using a lower temperature thermostat like the 160°F was to reduce the rate of evaporation of alcohol from the coolant to keep freezing point low. That is not an issue with ethylene glycol.

 

So basically, you should run a thermostat year round and if you are just using water, then you should use soft water and add a rust resistor/lubricant to the water.

[Desotodav]

.....others say that  flow needs to be restricted somewhat(by the thermostat)  to allow the coolant to stay in the radiator long enough to cool properly  before re-entering the water jackets.  I tend to side with the latter, but I'm no engineer, so I'm curious to know what others think about this.....

 

I found exactly that with my 218... the water flowed too fast without thermostat installed. I dropped about 20° after installing a 160° thermostat.

[st63]

Thanks for the input....I'm definitely re-installing the thermostat. It hasn't caused any issues running without it yet, but why take the chance.  As far as running water, I have run it in the summer in years past with just distilled water and a pint or two of rust resistor, but find that adding about a gallon (or 1/3rd capacity) of anti-freeze helps keep the system cleaner than just the rust resistor alone.  Just my experience....not definitive science!

By the way TodFitch, I've really found your plymouth33 site helpful as well, particularly the discussion of gear ratios, overdrives and such in the "how fast should I drive" page. Thanks.

[pflaming]

I grew up in the "Sandhills" region of Western Nebraska. Being sand based our water was pure. Proof is that Mom used well water in her steam iron for five + years before it started to show any deterioration. We could wash a black car with well water, rinse it off and there would not be one stain. I is amazingly clean water.

Our Model D John Deere tractors had a line that went directly from the radiator into one of the cylinders. On a long hard pull, we would turn on that valve and let water into the cylinder. It was like stepping down on an over drive. At the top of the hill we turned the water back off. We refilled the radiator every morning and every noon.

That was back in the '50's. I started driving tractor for harvest when I was 12 and worked all summer from age 14 on. Times have changed. Had two trucks a 47 ton and half Ford and a 2 ton 38 IH. We preferred the IH. My apologies for the rant. Administrators are free to delete if too far off topic. Sorry.

[chopt50wgn]

The t-stat allows the motor to build to the temperature of the given temp setting in the t-stat. So if you are running a 160, then when the motor gets to 160 it will start to open.

 All t-stats will open at said given temps, but they are not full open until 15 above the given temp.......example.a 160 is not full open til it hits 175 .

Also a motor needs to have heat in it to burn off any moisture in the oil and when running a 50/50 mix the pressure helps keep gaskets and seals tight.

[Don Coatney]

Here are a couple of quotes about thermostats from my old friend and forum member Grey Beard. This is worth the long read.

 

 

Aaron,
I really believe you would be happier with a 180 degree stat than a 160. The lower number stat harks back to the day when our Pilothouse trucks were built, and the only antifreeze was alcohol stuff that had to be drained out each spring, etc. and could not tolerate a higher operating temp because it would boil and dissipate down till it had no freeze protection. Today, when most antifreeze is ethylene glycol based, many newer vehicles carry thermostats made to open higher than 200 degrees, because the manufacturers want the engines to warm up quickly to get the computerized fuel delivery system into closed loop, where emissions are at their lowest.

With heavy engines like our flatheads, it is also good to get the operating temperature up near the 200 point. My own truck has a large size thermostat that is 195 degrees. When I drive the truck, the dash temp gauge never goes over 185, at least this time of the year. Maybe in warmer weather it will go up to 190 or 200, but with the overbuilt radiators and cooling systems built into our trucks, they seldom if ever had heating issues. Remember that these same engines were used in larger trucks that pulled their hearts out with heavy loads on a daily basis. AND if you keep a nice, clean 50/50 mix of antifreeze and water, the boiling point of the coolant is now up around 245 degrees. If we had pressurized systems - my 48 model does not have this - we would have boiling points over 250.

Having said all that, you can get the stat you need from (gulp) BurnBumm. Hate to recommend the guy, cause his bedside manner really lacks gravity, but sometimes you gotta' do what you gotta' do. Also, you could try Vintage Power Wagon, if you share the same aversion I have to businesses in Massachusetts.

Good Luck

 

 

Thermostats
It is impossible to operate an internal combustion engine without generating condensation in the crankcase. It is just a fact of life. If the moisture is removed, it presents no problem. If it is not removed, the result is an eventual buildup of sludge.

The only way by which the moisture of condensation can be removed from a crankcase is evaporation. This evaporation can only take place in the presence of heat and air movement. If the crankcase and engine block heat is not high enough for evaporation to occur, the condensation moisture will remain inside the block. Since this is water, which is heavier than oil, it will go to the bottom of the crankcase or valve chamber. It is for this reason that these are the areas where sludge is typically found in greatest quantity on tear-down. This writer has disassembled many of these engines were more than one pint of sludge was present in the valve chambers alone.

The best remedy for condensation removal is a high temperature thermostat. Vehicles built in the forties and fifties (and before) were designed to use alcohol based antifreeze. This required the use of low temp thermostats. Today we use glycol based antifreezes with much higher boiling points. Actually, the use of a 50/50 mixture of permanent antifreeze and water RAISES the boiling point of the coolant. All this is in aid of explaining why higher, rather than lower temperature thermostats are beneficial to longer engine life. The use of a 160 or 170 degree thermostat today with permanent antifreeze is an invitation for sludge to form in the crankcase. You are doing your engine no favor at all by keeping it running cool, in spite of how it may seem to your own sensitivities.

Not only do higher temp stats cause higher engine operating temperatures which aid in condensation removal, but they also help to raise the temperature more quickly, resulting in less cold engine operating time. Once stat temperature is reached, normal cooling will take place, but at a little higher temperature. Yet another reason why these flatheads need more heat than some engines is that they are heavy castings. A flathead six cylinder 218 cid engine weighs several hundred pounds more than a small block Chevy 350. This casting mass takes TIME to heat up and get up to operating temperature.

Many owners believe that when their dash gauge shows normal temperature, the engine is truly warmed up. Nothing could be further from the truth. Remember this one idea: an engine may warm up and the thermostat open to full circulation long before the block casting around the valve chambers has come up to full operating temperatures. It is this writer’s estimate that it takes nearly thirty minutes of engine operation for a typical flathead block to reach normal operating temperature in cool weather.

Please remember, I’m not talking about the thermostat or the top radiator tank, but the block casting, itself. This is where the condensation occurs and must evaporate from. In order to keep these block casting spots free of sludge, they must get up to full operating temperature. Proof that many of these engines have spent much of their lives running too cold is the sludge found inside the blocks. Granted, engine oils and filtration were of poor quality by comparison to today’s technology, but those engines that are run warmer are always cleaner. An example of this is the fact that larger truck engines are usually found to have less sludge than small trucks and automobiles. Check it out.

Consider a newly restored vehicle with a completely new and clean engine assembly. To keep this engine clean, it should not be started and driven short distances, again because the block will not have an opportunity to achieve operating temperatures. When I use my old stuff, I start it, let it run at idle for a while, then drive it, hopefully at least thirty minutes. I will jack up a car and push it in or of a stall to avoid starting a cold engine for only a few minutes, for this very reason.

It goes without saying that all this talk about getting engines up to temperature is doubly true for the exhaust systems. Exhausts live linger in an atmosphere where they warm up completely each time they are used. Why do you think tail pipes rot off three or four times before head pipes and mufflers? They are always cooler and warm up slower, since they are farther from the source of heat.

Cooling Systems
Cooling systems seem to be one of the more misunderstood components of older engines. In order to understand them, it is necessary to understand the combustion process. A typical gasoline engine running at 2000 rpm under no load will generate a certain amount of heat, but this will soon be realized and stabilized.

Add to this engine now an increased load on the crankshaft, and many things happen at once. First, in order to maintain rpm, the throttle plates must be opened further. This is done automatically if the engine is governed, or manually in an automotive application. The amount of fuel entering the engine increases, the result of which is an immediate increase in combustion chamber pressures and temperatures. It is this sort of use that cooling systems must handle in order to protect an engine. Normal driving under light load barely works the cooling system at all. It is at higher engine loads that the cooling system must be able to function well.

From the engine’s perspective and from a combustion standpoint, the hotter an engine temperature, the better and more efficiently the engine will. Fuel atomizes more freely and the combustion process thrives in an atmosphere of heat. This is difficult for many older vehicle owners to comprehend, yet it is fundamentally true . . . . . . Up TO THE POINT where the engine will begin to suffer metallurgical from the heat. Therefore, the job of the cooling system is to allow the engine to run as hot as safely possible in order to aid the combustion process, yet keep it cool enough to protect it.

Engines are designed to withstand lots of heat safely. Unfortunately, the margin for safety between “hot enough to run well” and “too hot for engine safety” is not a very wide one. When metal parts are heated, they expand. When they cool again, they contract. This cycle can happen over and over with complete safety, as long as the extremes of the heat range are not reached. If metal parts are heated so much that they do not contract to their normal tolerance after cool-down, the metal is said to have warped. This action is most often noticed on cylinder heads and manifold castings that have been subjected to hundreds of heat/cool cycles.. Typically, the remedy for a warped casting is resurfacing.

An example of this action is the typical small block Chevy cylinder head, where the valve arrangement is such that two exhaust valves sit adjacently in the middle of the cylinder head. This is nearly always the point of failure with these castings, for this is the hottest spot on the component.

How does this all relate to MoPar flatheads? The design of these engines is such that a water distribution tube is used in the cooling system to aid in dispersing coolant to the bottom of the exhaust valve seat castings. In this sense, these engines are truly overbuilt, for this is a feature not used by very many other manufacturers of the time. An analogy to this feature would be oil nozzles directed to piston crowns in modern diesel engines – a feature that goes far to extend engine life. Flathead radiators are also overbuilt from a size standpoint, and are truly impressive in their ability to transfer heat from the engine and transfer it to the air. When these engines are warmed up to 180 – 200 degrees F, they run happily all day, run more efficiently and stay cleaner. They live linger, as well.

Having said all this, the water distribution tube is a critical link in the cooling system. Never pull a water pump without at least pulling and checking the distribution tube. It goes without saying that no engine overhaul should ever be contemplated without inspection of this part as well. The tubes are reproduced by several vendors and are available.

Bottom Line
If you truly want to do the best you can for your MoPar flathead, here’s my recipe:

• Modern high detergent motor oil in a clean engine
• Full-flow oil filtration system in place of the part time bypass system
• PCV system instead of the primitive road draft tube
• High temperature (180 or higher) thermostat
• Good quality paper air filter instead of an oil bath system

[Eneto-55]

In my recollection I think Dad removed the thermostats in the summer but I may be wrong about that. I know we ran water only in our tractors and grain harvester engines.

 

Right or wrong, back when Dad had cars with flat heads he always did the same, and he worked in dealerships all his life.  Every Spring the thermostat came out, the block was flushed, and then refilled with straight water and no thermostat.  In the Fall Dad would test the thermostat in a pot of water with a cooking thermometer (Mom was pretty cooperative, in hindsight), then it was reinstalled & a water-antifreeze mix put in.  (These were all MoPar flat heads.  He stopped doing that when we got the 62 Newport 361.)

[pflaming]

If you think putting a thermostat on the stove was a stretch, do you recall your dad bringing in a new born calf and putting it in the bath tub, then rubbing it dry and left to warm up at the furnace. Different times.

[st63]

Good info from everyone....the "grey beard" post seems pretty definitive to me, and it's much appreciated!

 

And pflaming, I enjoyed the reminicense about the tractors and trucks back in the day....reminds me of summers on my grandfathers farm in northern Cananda in the 60s, with his old IH and John Deere equipment...he taught me to drive on a 49 IH 1 ton flat bed with a non syncro tranny.....simpler times.  

[P15-D24]

Sorry strongly disagree about running a 180 or higher stat in a stock non-pressurized cooling system. You will run into problems on warm/hot and under heavy load. With the stock system water will boil at 212. My moving up to a 180 or higher  stat you have substantially reduced your cooling capacity headroom by artificially making the water 20 degrees hotter (or more). If your running a 12-14 pound pressure cooling system (typically boil occurs at 245 degrees) it will work fine and you have plenty of additional cooling capacity. However you can't run a stock flathead at 12-14 pounds as the freeze plugs will blow out. If I remember correctly the 180 is only recommend for extended cold weather use. 

Have a non pressurized cooling system, use the 160 stat and add a proper pcv systems for best results. Doesn't matter it you run water or antifreeze mix. (I prefer distilled water with antifreeze)

[Robert Horne]

I have run my 38 Coupe for a lot of years without a thermostat, 50/50 all winter, all water all summer.

When I finally got my Coupe on the highway, I used all water no thermostat, all summer, and changed the water about every week or so until fall. The car ran about 160 on hot days, and 130 on cool day, to the cruise ins on Saturday evenings. These were short distance, about 25 minutes, so really not much time to heat up the engine mass, and about 4 gallons of water. In the fall, installed a 180 stat, drained as much water as possible, including heater, and installed 100 % antifreeze. As an experiment, I am still running all antifreeze. The Coupe runs 180 on cool to 85 degree days, and runs up to near 190 for a couple of minutes, and then back to 180. I do not drive on hotter days, as I would not do as well as the Coupe. On a 100 mile road run, the Coupe run 180 all day, with 100% antifreeze, 75 degree day.

I will have to try a road run on a hot day to see how the Coupe does, and I can take plenty of ice for myself............

[Jerry Roberts]

Antifreeze should be mixed 50% to 50% with water for better cooling . Some of the antifreeze comes pre mixed . But perhaps you got the results that you want . 

[st63]

Interesting stuff....so far, my experiment of running without the thermostat and with 2/3rd distilled water and 1/3rd anti-freeze mix, I'm running at about 180 on even the hottest, most humid days....I'll probably go back to the factory 160 thermostat by fall, just for peace of mind. 

[Jeff Balazs]

I have always considered running without a thermostat as a work around for some inadequacy in the cooling system. Any water cooled engine is designed to work best at a specific temperature. Removing the thermostat takes any accurate control of that temperature out of the system. Sure it may seem to help with some situations but isn't it really a better idea to address the real problem? With the thermostat out of the system there is really no way to know if your engine is really running at the correct internal temperatures. All you are really seeing at that point is the water temp at the sender. This isn't the condition the builder designed for.....and you have no way of knowing what might be running too hot or too cool or how it may affect the temperature of the lubricating oil.

 

If you are experiencing overheating problems and you have eliminated all other potential sources like a bad water pump, incorrect timing, a lean mixture..clogged cooling passages.. etc.... then the problem has to be in how effective the radiator is at dissipating the heat that is generated by the engine. It is really as simple as that. You may get by with borderline fixes in a cool environment but here where it does get very warm it does not pay to count on these types of "repairs". In most instance this condition can be corrected with a trip to the radiator shop for a recore or a simple tank and flush. Sometimes due to operating conditions an upgrade is called for. "Desert cooler" type radiators are fairly common here. These are simply a larger capacity - higher efficiency radiator. They work very well when the original equipment radiator is not quite up to the task. Generally there is no need for any other modifications. 

 

Jeff

I have always run about a 50/50 mix here. In my opinion there should always be some form of rust inhibitor in the cooling system. Most antifreeze already has this in the blend.

[Lumpy]

I've had good luck running a 190. The heat gauge (aftermarket) stays pegged at....wait for it....190 degrees. My oil stays very clean, and Lumpy always runs like that old Swiss Watch.

 

Now on a really hot day, like 90 degrees or more, if I get stuck in really bad traffic, she will eventually start to get hotter. I have considered switching to a 180 for that reason. But, that only happened once, at a Fairchild Air Force base air show, where all the cars leave at once...took over an hour, moving one car length at a time, to get off the base. Otherwise, I stay out of town, and the nearest city, Spokane, really rarely gets any kind of gridlock, hardly moving serious type traffic jams...if any, or of the kind that would send Lumpy into heat stroke...and again, even a small city is not where I enjoy driving Lumpy most, so it's not too hard to stay in the country on a hot day...or stay home! Or do something else. 

 

ken.

[TodFitch]

Interesting stuff....so far, my experiment of running without the thermostat and with 2/3rd distilled water and 1/3rd anti-freeze mix, I'm running at about 180 on even the hottest, most humid days....I'll probably go back to the factory 160 thermostat by fall, just for peace of mind. 

 

Factory service manual says thermostat to start opening at between 157° and 162° and is fully open at 183° and 187°.

 

I think that the opening temperature is the one that is listed on the box so that makes it a 160° thermostat from the factory. Never really looked into that before to see what they actually specified.

 

Interestingly, the 1934 service manual lists opening at between 150° and 155° and fully open at 172°. The '33 and '34 engines don't have the full length water jackets nor the water distribution tube so maybe the slightly cooler thermostat was needed to keep the hot spots in the engine at bay.

[meadowbrook]

My gosh, how complicated. I have run my 50 Dodge's 230 with 50/50 antifreeze and a 180 degree tstat for about 4 years now and it has a 4 psi radiator cap. No issues at all. Runs at the 3/4 position on the gauge all day long and never boils over or overheats, even when idling in 90 degree weather on a parade. Original, never rebuilt engine and radiator and a rebuilt water pump from napa. Is this wrong?

[Lumpy]

Sounds very right.

 

Even that one time Lumpy got her hottest, she didn't boil over...I just shut her off before the gauge went too high, but I don't remember now how high it did go.

 

Compression may have something to do with it, as Lumpy's is much higher than normal, or stock. Other than a parade situation, or the air show which was worse than a parade, she stays rock solid at 190 all the time, even going up hills.

 

ken.