'36 Buick overheats

[copperjohn]

The old Buick runs a little towards the warm side as the weather in Arkansas starts to heat up. I'm wondering if removing the thermostat would be an advantage or cause a problem of another nature. Anyone know?

[Guest OLBUICKS]

I would think removing the thermostat would make it run hotter because the fluid is going thru the radiator too fast to cool the the water.. The thermostat slows the movement down to cool it... I would put a low temp in there to try that..

[Grandpa]

There are several problems that can cause a vintage Buick eight to run too warm or over-heat. The primary causes are: (1) Rust deposits in the back of the block, (2) Rust deposits that end-up plugging the radiator, (3) A cooling system by-pass valve that is open.

To check on rust deposits: (1) Install a Gano in-line coolant filter in the upper radiator hose. If the filter picks up rust particles in a hundred or so miles, the block and radiator need to be cleaned. (2) Remove the engine block drain plug (located near the starter). If there is no water flow or low water flow out of the drain opening, the block needs to be cleaned.

Suggestions: (1) In the short-term, run 100% purified water, with water wetter added. This change will lower the operating temperature a little. (2) Install a 1950-52 Buick Roadmaster five bladed fan. This change will impove low sped cooling. (3) Made sure that the heater valve is 100% closed, as the heater water flow bypasses the radiator.

Grandpa

[Guest imported_JPIndusi]

If the radiator is clean and not plugged, the timing is on the mark (not late), fan belt not slipping then I would replace the thermostat with what is called a "heavy duty type". These are so called large opening thermostats and come in a blue and yellow box, marketed by Robertshaw or similar name, available at some auto parts stores in the performance section. Also availble from Bob's Automobilia. The opeing for the water flow in these types is considerably greater than "standard duty" ones and you should notice the difference, especially at slow speeds.

Joe, BCA 33493

[Seldenguy]

The Buick spec sheet for all the '36 models show the proper operating temp for the themostat to open is 140 -- 150 degrees.In MHO this would be my first check, and then persue the above suggestions. Bob

[Guest imported_JPIndusi]

Thermostats that open around 150 degrees F are hard to find. Buick actually listed one for 150, 160, 180. These were the old bellows type actuated with a relatively large opening.

Joe, BCA 33493

[JoelsBuicks]

CopperJohn, to answer your question, given everything else working properly, removing the thermostat would make the car run cooler because the radiator would see unrestricted flow and its ability to remove heat would be at a maximum as long as there was no other way to increase the flow. HOWEVER, there would be no advantage in doing this if indeed everything else was working properly. You can remove the thermostat and see what the difference would be but if the thermostat was working correctly, you would only get very marginally improved results. Also, removing the thermostat could indeed cause some minor problems like efficiency loss and slow warmup.

Before you go any further, there are a couple things that you can do. First, check to make sure the pump is circulating fluid. Open the radiator and watch as the car heats up. This might also give you a good idea as to whether or not the thermostat is working. Low circulation could indicate a bad pump, a plugged radiator, or an open bypass. I'd check the bypass first.

You could also run the pure water with water wetter and the improved thermal conductivity of just water will allow more heat transfer to the water from the engine and then to the air at the radiator. If I recall correctly, pure water has nearly 50% more thermal conductivity than 50/50 antifreeze/water.

Last but not least, my bet is that your radiator is suffering from some sort of plugging, be it on the air or water side. The only reason I say this is because it seems that nearly every overheating situation that I've experienced or read about and where the owner has extensively tried and failed to remedy, ends up being the radiator.

Good Luck,

[Grandpa]

Copper John,

The attached file is a specific heat chart for antifreeze. At 200 F and with a 50/50 mixture, antifreeze is only about 86% as good as pure water in transferring heat.

Grandpa

[JoelsBuicks]

Thermal Conductivity and Specific Heat Capacity are two unrelated physical properties. Thermal conductivity is a measure of a material's ability to conduct a certain amount of thermal energy over a period of time and area. Heat capacity has no time function. The thermal conductivity of water is 0.61 W/mK (Watts per meter per degree Kelvin) and 50/50 mixture has 0.41 W/mK. So, the heat transfer rate of pure water is 49% greater than the 50/50 mixture. The heat capacity describes how much heat is in the fluid going to the radiator and so pure water would contain more energy than the 50/50 mixture. So, the benefit in cooling ability with pure water vs. 50/50 mix is due to both thermal conductivity and heat capacity and the impact is indeed significant.

[jeff]

Given that the other benefits of antifreeze are rust prevention and pump lubrication, and looking at the chart and explanation from Joel, I going to run about a 25 - 30% solution. Sounds like a good compromise if everything else is working ok.

Has anyone consulted the shop manual? There is a section on using the "new" glycol-based products. Sounds like the previous choice was alchohol-based, with the huge disadvantage of gradually evaporating with heat. Most interesting are the comments on what not to use: honey, salt, some other old time remedies. So, stay away from these!

Jeff