Thermostat question

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Actually there is no rock solid explanation of what a thermostat change will do for you until you do it. IF you have one that is defective, sticking open or closed etc. I had a 440 Demon that was fine until you stopped, fan and shroud were good, 3 core radiator all in good shape but, pull into a drive through and it would boil over. I put vent holes in the fender wells, blocked the bypass, 165 T stat. Still no luck. Put a 195 T stat in it and it ran cooler in all situations than ever before with no more boil overs.
 
mguner said:
Actually there is no rock solid explanation of what a thermostat change will do for you until you do it. IF you have one that is defective, sticking open or closed etc. I had a 440 Demon that was fine until you stopped, fan and shroud were good, 3 core radiator all in good shape but, pull into a drive through and it would boil over. I put vent holes in the fender wells, blocked the bypass, 165 T stat. Still no luck. Put a 195 T stat in it and it ran cooler in all situations than ever before with no more boil overs.
Click to expand...

They are not created equal as well. The store brand I started with has a floating rivet and hole to help bleed the air, seemed good but it restricted the flow. Changed to a Milodon high flow 185 and there was a substantial difference when the components were re-shot with the laser. Head and upper block temps dropped drastically. My radiator was working fine according to the laser with about a 60 to 70 degree drop from top to bottom. Problem seemed to be nothing but good flow. My temp difference on the radiator are lower now but over all the temps are around 190ish!
 
Yes OEM. 355 gears only power is steering. Can't remember if anyone earlier asked but how sure are you about the accuracy of your gauges?

Also just a possibility, have you looked at your cap? Those things dry up or the springs get weak. I think Auto Zone or NAPA have testers for use. Should be a 16 lb cap.
 
62 dodge said:
I got mine from auto zone...hope it's good.
Click to expand...

I wouldn't "hope" it's good. You can put them in a pot of water on the stove and boil the water. Combine that with a thermometer and you can check the opening temperature and make sure it's opening completely as the temperature of the water goes up. Definitely worth checking. If the thermostat isn't opening all the way it will cause a restriction that could be limiting your water flow enough that the radiator can't keep up without more air movement.

I've also found that some of the more generic thermostats that are marketed for these cars don't have a wide enough shoulder on them, so, they don't get held in place properly. If the thermostat is moving about it won't work right either. I bought a Mr. Gasket high flow thermostat from Summit that was listed for a small block, except, it doesn't fit the water neck properly.

Looks like this. Shoulder on the thermostat isn't wide enough for some water necks
mrg-4366_ml.jpg

Problem solved. Should look like this with a wide shoulder
sum-361-180_ml.jpg
 
72bluNblu said:
I wouldn't "hope" it's good. You can put them in a pot of water on the stove and boil the water. Combine that with a thermometer and you can check the opening temperature and make sure it's opening completely as the temperature of the water goes up. Definitely worth checking. If the thermostat isn't opening all the way it will cause a restriction that could be limiting your water flow enough that the radiator can't keep up without more air movement.

I've also found that some of the more generic thermostats that are marketed for these cars don't have a wide enough shoulder on them, so, they don't get held in place properly. If the thermostat is moving about it won't work right either. I bought a Mr. Gasket high flow thermostat from Summit that was listed for a small block, except, it doesn't fit the water neck properly.

Looks like this. Shoulder on the thermostat isn't wide enough for some water necks
mrg-4366_ml.jpg

Problem solved. Should look like this with a wide shoulder
sum-361-180_ml.jpg
Click to expand...
I did just that. It opened around 197. Did not look like it opened a lot, just a little, then got larger the more heat.
 
62 dodge said:
I did just that. It opened around 197. Did not look like it opened a lot, just a little, then got larger the more heat.
Click to expand...

That's how it should work, they don't open fully right away. But they should open completely with enough heat, if it doesn't you won't get enough flow. Sounds like you tested the new 195* thermostat? Once you swap it in you can check the old one too. Sounds redundant because if the 195 thermostat fixes your problem you know it was the old thermostat, but knowing for s fact that the old one wasn't working right it gives you a little more piece of mind. Plus it's easy enough to do.
 
put a 180 Milodon in it and it still over heats. I think I'll just get rid of it......
 
I remember you said you have a serpentine set up on it? Just a thought, are you sure the pump is turning in the right direction? Can you post some pictures of your set up?
 
I once had an overheating problem and eventually changed the water pump , which had lost 3 or 4 blades, by internal mayhem, not corrosion.
Never figured out what caused it, never happened again.
 
SGBARRACUDA said:
I remember you said you have a serpentine set up on it? Just a thought, are you sure the pump is turning in the right direction? Can you post some pictures of your set up?
Click to expand...

That's a good catch, magnum serpentines spin the water pump the opposite direction. Also, a lot of aftermarket serpentine systems have underdrive pulleys. More horsepower, but less flow. So, what kind of serpentine system is it and which way is the water pump turning?

But, 220 in traffic and fine on the highway? That's not insanely hot. I mean, it's too hot, but that could just be the lack of a fan shroud with that mechanical fan. You lose a lot of efficiency without a shroud.
 
1969383S said:
They are not created equal as well. The store brand I started with has a floating rivet and hole to help bleed the air, seemed good but it restricted the flow. Changed to a Milodon high flow 185 and there was a substantial difference when the components were re-shot with the laser. Head and upper block temps dropped drastically. My radiator was working fine according to the laser with about a 60 to 70 degree drop from top to bottom. Problem seemed to be nothing but good flow. My temp difference on the radiator are lower now but over all the temps are around 190ish!
Click to expand...
I changed it to one and it still does the same thing....
 
SGBARRACUDA said:
I remember you said you have a serpentine set up on it? Just a thought, are you sure the pump is turning in the right direction? Can you post some pictures of your set up?
Click to expand...
can't post any pictures, but I'll check the direction it turns.
 
So, clockwise or counter-clockwise?

The standard LA pumps turn clockwise looking at them from the front of the car.
 
Ok. I checked out CVF and all of their small block serpentine systems still spin the water pump clockwise. So, unless you bought a counterclockwise water pump you should be fine.

Do you know what # radiator you have? dgibby has a repop stock fan shroud on his Champion 526....
image-jpg.1714817789

image-jpg.1714817790


Here's the thread fan shroud champion rad
 
I'm thinking I'll have to have one made for mine with the serpentine belt system set up.
 
I don't think it would matter, the serpentine system probably doesn't stick out any further than a stock pulley set up with A/C and power steering. I mean, this is the full system from CVF. The belts are really wide, but there's only two of them. The stock A/C and power steering set up ran 4 belts. And you can see on the water pump pulley that the centering button still sticks out from the pulley, so the face of the water pump pulley isn't any further out. Unless the crank pulley sticks out further (and it shouldn't based on the picture), the fan would end up in the same place as on a car with the stock pulley set up.

360-SERPENTINE-AC-2.jpg
 
The power steering pulley is only 2" from the rad and sticks out about 1/4" past it.
 
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