Opinion

[TMarsh]

Live in NE Texas, temp. extreme 0-100+F, daily driver. Do you have a thermostat in your car? If so, what is the temperature of the stat, where is it located, top of hose, near block or near radiator. Do you secure it in the hose.
My coupe runs cool but fine without thermostat and runs warmer with one. Just replaced the head gasket, silicone, with copper because of leak into cooling system, decided to take out 160 thermostat and try running it without. Other than temp, seems to run fine as is. Just asking for your personal opinion, and I know it depends a lot on your location.

[BRENT in 10-uh-C]

In a nutshell, often times people modify their Model-A because they compare it to a modern vehicle (-which has a totally different design on the cooling system) with the mindset that that they need to modify it so it will be more reliable. The main reason why Model-As have survived thru the years is because their original design worked so well.

[JayJay]

Sf Bay Area, moderate temps but can get into the 90s and higher. I had a 165 thermostat in a Vintage Precision housing but was constantly overheating to 200+ when climbing. I took it out and now rarely get that hot. I’m leaving it out.

Interestingly, I was on a trip up the California/Oregon coast a few weeks ago. Got some long downhills and the temps were well below 140! I thought the gauge was broken but once it got a load on the flat they came back up to the 160 range.

[Jim/GA]

The Model A cooling system was not designed for a thermostat in the coolant hose.

In NE Texas in the winter, you should run what they used back in the day, a radiator cover that partially blocks the flow of air to the bottom 1/3 or so of the radiator. You see them on eBay at times.

You can make one quickly and easily from a corrugated plastic sign board (like you see for ads stuck by the side of the road). Cut the width to match your radiator shell. The height is not critical. I hang mine with 2 velcro straps from the headlight cross bar and slip it behind the radiator shell. You can get black plastic sign board and it disappears on the radiator.

[Y-Blockhead]

I run a 160°F thermostat only because my engine runs cooler than what I prefer. IMO, it is better to run an engine warmer to help evaporate the BAD stuff from the combustion process that ends up in your oil (water, acids and unburned gas). My temperature gauge rarely sees 180°F when the thermostat is open.

But to each his own...

To answer the Ops question, I have my thermostat at the bottom of the hose, held in place with a hose clamp. I drilled 2 ⅛" holes in the thermostat to ensure there is flow when it is closed.

[BButturff]

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I have a 160°F thermostat, unmodified, in the bottom of the upper hose and held in place with a hose clamp. Without the thermostat my engine runs too cool here in SE MN. On a 90° day the engine runs 185°F.

[Jim Brierley]

I run a 180 degree stat in the upper hose. It is important to drill at least 2 1/8th holes in the stat to allow water to circulate, if you don't, the temp will fluctuate a lot. It is better to run the engine hot to, as Y-Blockhead says, to evaporate the bad stuff (moisture) , in the entire system, i.e., oil, muffler, etc.

[32Ford13]

160 thermostat, six blade fan. Not a problem with cooling in the hot summer months. Does run a bit cool in spring and fall, but not an issue.

[Herb Concord Ca]

I have a Vintage Precision thermostat housing on both my Model A's has a 160 thermostat in each. Cars run at 170 on temp gauge year round. On a hot 95+ day the gauge goes to 180.

[Gene F]

160F upper, six blade, and the biggest radiator that Snyders sells. I also have a temp gage, with a probe in the neck atop the HC-head. System works fine. If I don't run the T-stat the thing runs quit cool.

[nkaminar]

I have a 4 year old Berts radiator. I run a two blade fan and a 160 degree thermostat at the bottom of the upper radiator hose secured with a hose clamp. I used to take it out in summer but I have enlarged the hole in the flange to maybe 3/8 inch and now do not need to take it out in summer. The coolant temperature measured at the goose neck (coolant outlet at the top of the head) runs 160 degrees summer or winter.

The problem with the smaller hole was that not enough coolant was circulating to properly operate the thermostat. The engine would get really hot, then the thermostat would finally open, and a slug of hot coolant would flow to the radiator. The coolant was hot enough to overflow out the overflow tube and radiator cap. Then the coolant would cool down and the thermostat would close again and the cycle would repeat. This cycle burped out coolant to the point where I would have to add some, about a gallon.

With the larger hole there is enough flow to properly operate the thermostat. It not so large that the thermostat does not do its job in winter. No more burping out coolant. Now I never add any coolant and only open the radiator cap to add coolant when I have drained the radiator to work on the engine.

[Mulletwagon]

Run without a Tstat year round here on the Florida Panhandle with no problem. In very cold climates a Tstat is recommended because running a cold engine accelerates wear and combustion is less efficient. Blocking the radiator with cardboard would require some experimentation and require temp gauge.

[P.S.]

I'm in NE California. Winters get below freezing, summers get over 110 degrees. No thermostats in any of my Model As. No problems.

[Bob Bidonde]

I run 160F thermostats in both of my Model A's and I have been doing so for many years. I also have temperature gauges in the cars, and both cars run at approximately 160F. I had one thermostat fail and it stayed closed that caused the engine to overheat. The engine's temperature was so hot it melted the solder in the REX-A-CO temperature gauge sensor, so the ether leaked out. I have switch to APCO temperature gauges that us a thermocouple in lieu of a Borden tube.

[TMarsh]

Thanks for all the input. With that said I believe I will leave my thermostat out. I have a daily driver and just finished a long parade in low gear in upper 80's weather and the temp never got over 160. By the way, it is not just a parade car. Google Yamboree for a look at the festival.

[Russell Reay]

Originally Posted by Bob Bidonde

I have switch to APCO temperature gauges that us a thermocouple in lieu of a Borden tube.

I just read your comment about using an APCO temp gauge with a thermocouple instead of a Borden tube. I have never heard of a Borden tube, but assume it is a pipe connecting the subject fluid to the gauge itself. I assume, again, that a thermocouple transmits an electrical signal to the gauge. The usual vendors' parts descriptions make no mention of thermocouple or Borden tube--just connection to the radiator hose or pre-drilled neck. How do I know what I am getting, or is there a specific source for the thermocouple version?

[Planojc]

I'm in Texas and no thermostat.

[john in illinois]

I have run a 165 thermostat in my Tudor. for 20 years. Temp always between 160 to 180.
29,00 miles.

John

[Y-Blockhead]

Originally Posted by Russell Reay

I just read your comment about using an APCO temp gauge with a thermocouple instead of a Borden tube. I have never heard of a Borden tube, but assume it is a pipe connecting the subject fluid to the gauge itself. I assume, again, that a thermocouple transmits an electrical signal to the gauge. The usual vendors' parts descriptions make no mention of thermocouple or Borden tube--just connection to the radiator hose or pre-drilled neck. How do I know what I am getting, or is there a specific source for the thermocouple version?

I would imagine a thermocouple gauge would have a wire running from the sending unit to the gauge. The Borden tube would have a heavy "capillary" filled with gas from the Borden tube to the gauge.

Mechanical Temperature Gauges are Borden tube type.

[The Master Cylinder]

Originally Posted by Bob Bidonde

I had one thermostat fail and it stayed closed that caused the engine to overheat. The engine's temperature was so hot it melted the solder in the REX-A-CO temperature gauge sensor, so the ether leaked out. I have switch to APCO temperature gauges that us a thermocouple in lieu of a Borden tube.

Your temperature gauge didn't indicate the engine was getting hot before it melted? And in this situation was it the fault of the design of the gauge? I have always run Stewart Warner Mechanical Temperature Gauges. I find the 270° sweep gauges easier to read.

Another good reason to drill a couple of ⅛" holes to ensure there is some circulation.