The Stovebolt Site Forums The Shop Area Engine Shop No thermostat?

It's a '55 235 in my '46 Chevy 1/2 ton with a freshly recored original radiator and a short shaft water pump. My understanding is that the thermostat stays closed when first starting up in order to allow the water temp to get to 180 degrees. When the temp goes over 180 I'm guessing the therm. opens to its max to allow the most coolant to cycle thru the radiator. So, here in So.Cal. Do I even need a thermostat? Also, what is the closest the fan can be to the radiator? I'd like to be running a little cooler than the 190 or so when it's 65 degrees outside. I'm worried about when it gets to be 90 or 100 in the summer. Any thoughts?

Anzan

The thermostate regulates the temprature of the coolant to keep it at consistant temp. Opening up to cool the temp, and closing to warm the temp. As long as the coolant passeges in the block are open and the block does not have sediment built up in the bottom and the radiator is not partially plugged you should be o.k. (unless your in bumper to bumper traffic at a stand still for long periods of time). If your still worried, thermostates have differnt heat ranges (165,180,195) and you could change to a lower temp. You could also step up to 5 or 6 bladed fan, or add a fan shroud.

You should keep a thermostate in as the engine has a recomended operating temp recomended by manufacturer for best operating results.

Just my thoughts,

a little more - you should definitely have a 'stat because having no restriction at all in the flow will result in the engine overheating because the water will be flowing too fast to pick up enough heat and not staying in the rad long enough to cool well

the thermostat sets the minimum temperature, the maximum temp shouldn't be much above the rating if the system is a A-OK, running at 190 with a 180 stat isn't unreasonable, but with a 235 it should really be closer to 180, providing you're using an accurate gauge or thermometer - if so you might have a poor 180 stat, and certainly in your area you could be using a 160, but never trust an old truck temp gauge, check various points on the engine and rad with a non-contact laser thermometer

Bill

I ran my truck for 25 years, (every car I ever owned that I needed to replace the thermostat for that matter) with a 195 degree thermostat. A couple of those years were in san diego.
You need the thermostat to keep things constant, too cold is not good either, and as the other fella said it can lead to overheating, as it doesn't allow time to dissapate the heat in the radiator. They didn't just put them in for kicks.

Thanks guys, I'll be putting in my thermostat. Somewhere in my fogged memory I've been told this before...I've already tested the stat in a pan of water and it is working so back in it goes.

Is there a certain place to get a shroud that will work on my old radiator?

the fan should provide sufficient cooling if it's within 1/2 - 3/4" of the rad and pretty much centered on it - another thing that may affect cooling is a pressure cap, your 46 rad may not take a pressurized cap without having the fill neck replaced, but the 235 in 55 would have had a 7# cap .... you'd need to check around hot rod parts places for a shroud that would work for your particular configuration, or fab one yourself, but set up everything else first before you decide you need one .... in my experience, the 235's tend to run cool if you let them, a 160 stat might satisfy you

Bill

the water will be flowing too fast to pick up enough heat and not staying in the rad long enough to cool well

Thanks, no thread would be complete without that.

Got it. I'll measure the fan distance tomorrow. Thanks again

I had a rig come in the shop years ago with visegrips pinching off the lower radiator hose to "correct" this condition.

back when I lived in the desert, folks would remove the center functioning part of the stat, leaving the large washer-like mount plate to restrict the size of the passage, hence slowing the flow - particularly common with the Ford flat motors

Bill

I know I will never convince everyone about the necessity of a thermostat but for those interested check out my Blog for more info. Thermostat Myth

A variation of that trick was to use 3/8" fender washers in the thermostat housings.

How about some firsthand experience. I've run 2 different engines without thermostats, one a performance engine , the other stock; both in the summertime. In neither one could I ever get the engine up to operating temperature no matter how hard I ran them.

With out a thermostat the coolant has no time to cool in a hot climate. In a cold climate the coolant has no time to warm up.

I remember (amazing) in my youth the hot rodders would remove every other blade from both water pumps in the flathead fords to slow down the water. The v8 in my 48 ford woody had that done to it before I got the car. Never really had a cooling problem that I can remember.

If you are replacing that Thermostat look for the new type that if they fail they default to the open position not closed.

Just a thought

You can a high flow thermostat from Auto zone in three heat ranges and help quit a bit. i have one and cooler weather it does not heat up enough. they say for racing only but i have been using one for 3 years.

I finally solved my overheating problem by moving the dist gear one tooth and re stabbing it. Now it gets up to 180 when pulling a long grade. Had to install a new vacuum advance and when replacing the dist missed it by 180 degrees. Re stabed it and it would still heat up. Moving it one tooth solved it. I think it moved the rotor clockwise.

In my experience, the clocking of the distributor doesn't matter as much as the actual timing. However if you can't move the distributor to get the proper timing, you might consider trying to move it a tooth. I find it easier to move the wires one spark plug hole and retime the engine. 5 degrees before upper dead center and good to go.

Bigbad, I no sooner got it running cool and decided to rebuild the whole engine. I'm going to a HEI type dist this time and will put a very visible mark at TDC while its apart. This engine sat in my boneyard for 25 years and I had no history of how it ran. Got it going and the rockers were so worn out I figured the bottom end would be worn as well. This way Momma won't mind riding shotgun since there will be less chance of a tow truck in the picture.