Thermostats

civilwarlife

civilwarlife

Member
I just took off my upper radiator hoses and no thermostats! I wonder why. One kind member tild me I need 180 degree thermostats and I should drill a hole in the flange. My questuon is what holds them in place, and what is the hole for?
Thank you all profusely again.
Terry Thomann
 
Another clamp holds them in place.See pic
 

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I was told by a prior owner that the stats on my ‘36 Phaeton had indeed received the old hot rodder trick of the drilled hole. Lo and behold, when replacing hoses recently, there were no thermostats at all.

For now, I’ve opted to run without since I don’t drive in colder months (road salt, etc) and recent coil / water pump rebuilds have eliminated all prior overheating symptoms.

Since the thermostats are in the upper hoses and readily accessible, you might try experimentation as there seems to be a wide variety of opinion and road experience.
 
The hole is to allow the trapped air to escape to the radiator when you are filling the cooling system after installing the thermostat. If there is no hole air gets trapped against the thermostat and it will take longer to open than when there is coolant contacting the thermostat. Modern car thermostats use a "jiggle pin" for this reason. A simple hole works fine for us.
 
I use a 1/8" hole located at the top when installed. Racers would either gut the thermostat or use a round plate with a large hole in the center. This was to restrict the flow of the coolant to the radiator similar to a thermostat. This was to slow the flow of coolant through the radiator for optimum heat exchange.
 
question civilwar life which flathead are we talking about all flatheads have thermostats but they are all held differently from early to late helps to narrow it down
 
Another reason for the holes besides letting air through: The thermostats will not open until the temperature of the water actually at the thermostat reaches the temperature for opening. If the thermostats are up in the hose, or even sitting on outlet on top of the head, the hot water in the heads is not moving up to the thermostat, because the thermostats are completely blocking the flow. The holes allow a little flow even with the thermostats closed so that the opening can react to the water temp in the head, not just the water blocked at the thermostat.



I have 170 degree thermostats in my '41 and had overheating problems, so I watch the temperature gauge like a hawk. Upon starting up the temperature gauge would go to over 200 every time, and then drop to 170. Not a real problem, except for the anxiety. So I drilled two 5/32 holes in the edge of each thermostat; now when starting the temp rises to 170 and holds there. The holes may slow warm-up by a minute, but that is also not a real problem.
 
I would think the thermostats should be close to the motor and not at the top of the radiator. If your water is low, how will it work correctly if it's above the water level?

Regards
Bill
 
drolston said:
Another reason for the holes besides letting air through: The thermostats will not open until the temperature of the water actually at the thermostat reaches the temperature for opening. If the thermostats are up in the hose, or even sitting on outlet on top of the head, the hot water in the heads is not moving up to the thermostat, because the thermostats are completely blocking the flow. The holes allow a little flow even with the thermostats closed so that the opening can react to the water temp in the head, not just the water blocked at the thermostat.



I have 170 degree thermostats in my '41 and had overheating problems, so I watch the temperature gauge like a hawk. Upon starting up the temperature gauge would go to over 200 every time, and then drop to 170. Not a real problem, except for the anxiety. So I drilled two 5/32 holes in the edge of each thermostat; now when starting the temp rises to 170 and holds there. The holes may slow warm-up by a minute, but that is also not a real problem.
Click to expand...

I can vouch for this. I put new 160 degree thermostats in my '51. The first time I took it out after installing them, I saw the (mechanical) temperature gauge go steadily up to almost 200 degrees. While I was thinking about pulling over to check things out, it went quickly down to 160. It happens every time, but I've gotten used to it.
 
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