The Stovebolt Site Forums The Shop Area Engine Shop do you really need a thermostat installed

Got to looking at my 50 1/2 ton chevy and theres no thermostat installed in the housing
is this an issue, never had overheating issues
but did have overflow drain out a little sometimes and i just thought i had overfilled but maybe the lack of thermostat is issue
Thanks for reply
Ken

Yes,, you do need a thermostat. It keeps your motor at a certain temperature,,and by removing it,,it lets the water run thru the radiator too fast without cooling it,,therefore overheating.
Marty

Without a thermostat your engine can, and will, run to cold and burn more fuel. These engines like to be about 160-180 for best performance and economy.
Grigg

What the others said.

Well, one says hot the other cold. :hammering:

I'm not an engineer but my understanding is that the purpose of a thermostat is not to keep the engine cool but to let it warm up quickly and keep it at a more efficient operating temp. A stuck open thermostat most often leads to a complaint of a heater blowing cold air. I've never heard of a stuck open thermostat leading to overheating.

Yes, you need a thermostat. The reason for the 160 degree stat years ago was for engines using alcohol-based antifreeze. Any hotter minimum temperature would evaporate the alcohol. When ethylene glycol-based antifreeze got popular, the standard stat became the 180-degree type, since ethylene glycol has a higher boiling point, similar to water.

Today's thermostats are usually in the 195 degree range, give or take a few degrees, because hotter-running engines tend to be more fuel-efficient when combined with high-pressure radiator cores and 16-21 lb. pressure caps. The proper thermostat/cap/radiator combination for mid-50's and newer stovebolts would be a 160 or 180 stat, and a 7-lb. radiator cap. Be sure the radiator is clean and free-flowing.

It's possible to flow coolant too fast through a clean radiator, resulting in not enough time for heat transfer from the coolant to the air. I used to install a flat washer with a hole about 3/4" in diameter on my race engines instead of a thermostat to control coolant flow.
Jerry

To add to Jerrys comments, the thermostat also acts as a flow regulator. This helps keep the flow from being too fast through the rad, allowing for more time for heat transfer. Using a washer in the housing does essentially the same thing, only there is no temperature control like with a thermostat. that was an old trick used with Flatheads back in the early days of racing.

I've had old cars that would overheat without a thermostat in them. I don't run an engine without one.

Meby it's just me but I've never owned, been around or heard of a vehicle overheating because of not having a thermostat. I guess I can no longer say I've never heard of it.

Depending on lots of variables, it is quite possible for any engine to overheat without the thermostat. This generally occurs with a long lower radiator hose which has no reinforcing wire. The thermostat prevents such a hose from being sucked shut, which shuts off the collant flow from the radiator to the block. Having had this occur, I still tend to replace extremely long lower radiator hoses with 2 short ones, and a piece of metal tubing.

Another instance (although not occuring with stovebolts) had to do with Smiths thermostats. One feature of many English vehicles was a bypass to allow quicker warm-up. The Smiths thermostat had a sliding ring around its perimeter that would slide into a position to close the bypass as the thermostat opened. Failure to include a thermostat or using a non Smiths thermostat would definately cause overheating.

Here is a link showing one of these:

http://abouttimespares.com.au/showpartslist.asp?cat=46&sub=979

Scroll down and look at part number Part No: X85025/80. The outer ring is the slide.

Jon.

Several of the above are correct. Have had the hoses sucked flat causing overheating. Also seen where the thermostat missing caused overheating. Even had it happen to me some years back. Also remember when black pepper was used as stop leak till you could fix it. I know, I did several times in different radiators over the years. It works. Smells like too much pepper on your eggs but its harmless and a cheap quick fix. As also mentioned you will use more fuel on a cold or just warm engine compared to one running at about 180. The principle is the same for carb or FI ones. On computerized ones, you MUST have one or your injectors will fire way too rich and won't lean out. The computer thinks the engine is still cold and will adjust it accordingly. May be a bit quicker but much more thirsty and higher emissions. Also will carbon up your engines' innards and catylitic converter and O2 sensor. Henry

J.... C.... Do you guys know everything about these Trucks?......................I did that pepper thing once..it does work...

Well, I have a question to add to this - I have an oversize radiator in with my 235 in my 50 pickup. The rad cap is 13lb - and that is what was there. The truck has aftermarket a/c so I don’t know if I should change in to a 7lb like HotRod Lincoln suggests.

I seem to run right at 180 and below running, but when at stand still idle, it can move up to 220 mark (the dot on the dial) then it will cool right down to 180 - I guess when the thermostat opens.

The thermostat is new (180) ... Just wondering if there is something to worry about.

Thanks, Rino

Rino, in your situation, I'd stay with the higher-pressure cap. The 7-lb. maximum serves to protect the old style honeycomb core. If it's got a heavy-duty tubular core, the higher pressure adds some insurance against boil-over when the temperature spikes. If you're getting a spike, then a quick cool-down, it's possible the thermostat is sticking closed occasionally. Even new ones can do that.

Every pound of pressure adds 3 degrees to the boiling point, so a 15-lb. cap allows a boil-over temperature of about 257 degrees at sea level, lower as you go up in altitude. Unless you're in traffic with the air conditioner on, or pulling a heavy load, etc., the temperature should be pretty stable at or near the thermostat opening temp, assuming you've got enough radiator capacity to cool the engine properly. One of the biggest mistakes some hotrodders make is to add a big engine without an appropriate increase in cooling capacity.
Jerry

just another thought. For those who maybe running an "original" style radiator be careful. you can change the radiator cap necks out to run a higher pressure on the radiator but if your running the THIN brass tanks on the core you can "rupture" or blow them open real easy!! For that reason I still run a low pressure cap on my set up and have had no problems except a little warm in parades!