Installing a thermostat in upper radiator hose

daveymc29

daveymc29

Well-known member
I did a search and found information on coolng problems but not installing a thermostat. I know I have seen stuff on that so I must be asking the question wrong. I have a temperature gauge that seldom gets of above 120 degrees. I have checked the block with an lazer beam Infared testers and my engine is at its hottest about 140 to 150 degrees between cylinders 3 & 4. I have a 180 degree thermostat that I soldered onto a short tube I made to just fit inside the upper hose. Tested it on the stove top and it works as supposed to. I believe that I should make a couple of holes to allow the radiator water to flow up through the hose when I start the engine or it may well overheat before the thermostat gets hot enough to open. Is this correct and if so how many and how large should the holes be? I'm running distilled water at the moment and thinking of changing to an antifreeze coolant. Suggestions there also?
Thanks in advance.
 
I drilled two 1/8" holes in mine, and I lock it in place as close to the engine as possible by inserting the barbed part of a 2" diameter plastic fitting that I cut off. 2" OD that is.
 
I may have screwed it up. I put four holes. My thought was to put it up at the top of that upper hose. Don't have any real theory on that, just the end of the hose I stuck it in. It's a very tight fit so I don't see it moving any time soon. And no place to go if it did. Maybe with four holes it will just take longer to warm up enough to open. I'll try to check it out tomorrow if it turns out to be a work in the garage day. If not, maybe Friday.
Thanks Tom
 
pretty sure for correct operation and less chance of overheating the engine before it opens it should be as close to the head / waterneck as possable
 
I don't think the extra holes will hurt too much, but it should be as close to the head as possible. Also, make sure the "pointy end" points toward the radiator.
 
The thermostat sold by snyders has just one hole in it. What harm is there to the motor if installed with out drilling any more holes in it. Which is what I did.

Thanks
 
Your stat should have had whatever holes it needed. The extra holes won't matter. You are fine with the stat where it is. Most end up at the top of the hose anyway. Will work just fine. Get antifreeze in there and keep it there.
 
DON'T put the thermostat at the top of the hose otherwise when it opens it will pour coolant out the overflow tube. You will go nuts trying to figure out why you keep losing coolant. The thermostat should be located just above the gooseneck and be secured with a hose clamp. I have heard of thermostats migrating up the hose causing the mysterious lose of coolant problem. Two 1/8"- 3/16" bypass holes are all that is needed. I wouldn't worry about the 4 holes you installed. If necessary apply some 5minute epoxy to plug the extra 2.
 
PRG999 said:
The thermostat sold by snyders has just one hole in it. What harm is there to the motor if installed with out drilling any more holes in it. Which is what I did.

Thanks
Click to expand...

Installing a thermostat without any bleed holes, completely blocks all pump circulation through the block.

It takes MUCH longer for enough heat to reach the stat in the hose, causing the water / coolant in the block to heat up to the point where it can boil, and since the upper (normal) path to the radiator is blocked by the closed thermostat, and the expansion created by the boiling coolant / steam will expand the only way possible: through the lower hose, and up through the radiator, pushing coolant out through the overflow tube, sometimes rather violently.

An 1/8" bleed hole (or two) in the flange of the thermostat mounting plate allows a little bit of coolant circulation past the thermostat capsule, and the block & radiator as well, which promotes more even warm-up, and allows the thermostat to be more sensitive to the actual temperature of the coolant in the block.

When automakers began incorporating thermostats into their designs (Packard and Cadillac in the Teens, to name two), they usually designed in a "by-pass circuit" that allowed the water pump to circulate coolant within the block until it warmed enough to open the stat and allow circulation through the radiator. Cars such as Hudson and Lincoln that employed thermostatic shutters in front of the radiator allowed circulation through the block and radiator at all times, and controlled warm-up by controlling air-flow through the radiator.

:cool:
 
There is a very nice one made by Vintage Precesion that replaces the goose neck on the top of the head. It holds the thermostat against the very top of the head. It also has ports for a temp gauge probe if that is something you want to add. vintageprecision.com.
 

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Use an old piece of lower hose which fits inside the upper hose to hold the stat in place, or toms pvc idea.... the outside clamps look like c**p
 
JohnLaVoy said:
There is a very nice one made by Vintage Precesion that replaces the goose neck on the top of the head. It holds the thermostat against the very top of the head. It also has ports for a temp gauge probe if that is something you want to add. vintageprecision.com.
Click to expand...


Now, if you wanted to be really slick, you could use this t-stat outlet, plus an inlet casting that is drilled & tapped for a heater connection, then run a small bypass-hose (1/2" or so) between the two.

Then you will have pump-forced circulation within the block when the stat is closed. :D

When the stat is open, the majority of the coolant will circulate through the big pipes, and the bypass circuit will be irrelevant. ;)
 
Davey, trust me,
Just poke the sleeved thermostat in the upper end of the upper hose. NO holes needed.
The water & the heat travels UP & it'll work FINE!
Minerva ran fine this way, for over 12,000 MILES.
Bill W.
 
I'm surprised that no one has commented "why go through all this work?" I will admit that I am a "traditionalist" and do not make many changes. But this looks like a good modification to put you on the road side during a tour when the thermostat goes south! If you do not have a water heater in the car there is no need to have the thermostat. If the carb is clean and has the proper flowing jets, no measurable improvement can be made.
 
JohnLaVoy said:
There is a very nice one made by Vintage Precesion that replaces the goose neck on the top of the head. It holds the thermostat against the very top of the head. It also has ports for a temp gauge probe if that is something you want to add. vintageprecision.com.
Click to expand...

Special Coupe Frank said:
Now, if you wanted to be really slick, you could use this t-stat outlet, plus an inlet casting that is drilled & tapped for a heater connection, then run a small bypass-hose (1/2" or so) between the two.

Then you will have pump-forced circulation within the block when the stat is closed. :D

When the stat is open, the majority of the coolant will circulate through the big pipes, and the bypass circuit will be irrelevant. ;)
Click to expand...

I have the Vintage Precision water neck that John pictured above. I also have a heater in the cab. Any time I have the heater valve open (which I can control from the cab) I get the "pump forced circulation" that Frank described.

The Vintage Precision water neck has built in a couple of 1/8" holes for water to keep flowing even with the heater valve closed. This device also makes it possible to change out the thermostat, should it become necessary, on the side of the road in 5 minutes. (Yes, I've done that. Have the T-shirt to prove it!)
 

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The Model A engine was not designed to operate with a thermostat. When the thermostat is closed water is not circulating in the block. On a cold day it may not open and you run the risk of burning up the number four piston.

Tom Endy
 
With a cold engine & a thermostat. Rev the engine & peer into the radiator, you'll be SURPRISED at the amount of water going into the radiator. It flows from the factory provided vent & "possibly" through the valve being pushed open slightly by the water pressure. DRILLING HOLES IS NOT NECESSARY! On modern cars, does the thermostat maker recommend HOLES???---Use your head!
Bill Cool
 
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