ENGINE GETS RED HOT

[CharlieS]

But, but, more coolant is moving around. Each pass picks up less but there are more passes???

This may be irrelevant but on my truck installing a thermostat with too large an orifice will ensure that the temperature gauge never leaves the cold pin and if it's cold out I'm even colder and trying to see through a frosted up windshield.

Empirical observations!

More coolant is moving, but the temp of the coolant being transfered from the radiator to the block is not as low with no tstat installed.
Thermostat = restriction which means the coolant has more cooldown time in the radiator, thus its a cooler temp when mixing/replacing the coolant in an engine.
The thermostat is nothing more than an automatic tempratiure sensing valve that opens when it senses too much heat, and closes when it senses not enough heat.

In your truck scenerio, i suspect there are other forces that come into play, however in any liquid cooled engine scenerio, too large of a radiator, for example, will make the coolant hard to heat to operating temp in cold weather, as will having the improper tstat installed. volume of liquid transfer from the water pump is a factor, diamater if hoses connecting block to radiator, or even a partial heater core blockage. An effecient cooling system is a well engineered package, not just any radiator, hooked up to any old engine. Too much total coolant capacity is as ineffecient as not enough coolant capacity. Radiator design is also important, in that how many square inches of cooling surface in how many rows of transfer tubes, whether its a cross flow, or vertical flow design and i'm sure other factors are involved.
These also would apply to any common liquid cooled engine design regardless of application.

 

[Egon]

temp of the coolant being transfered from the radiator to the block is not as low with no tstat installed.

Agreed on that but as there is no restriction the coolant flow is higher is it not.

Now on my truck as soon as we got a Thermostat with a smaller bypass orifice installed the engine warmed up, the windshield defrosted and I became much warmer.:thumbsup:

 

[rjkobbeman]

A thermostat is designed to keep an engine warm, not cool. If you remove the thermostat, your engine will run cool.

At some point, as outside temps get high enough, I imagine the thermostat stays open -- which would be like no thermostat installed.

 

[FredH]

Although A full open thermostat is allowing flow it is not the same amount of flow that no thermostat would allow , thus giving the the coolant time to cool as it passes through the radiator . Try pulling a long grade with a heavy load or even a heavy trailer first with a thermostat then with-out .


If thermostats were not required , why would virtually every type motorized vehicle have them ? It is not like they are making money on a $3 or $4 part .
But as I mentioned before , a brand new $4 thermostat almost stranded a $40,000+ boat .

Back to the thread though , I would start simple as my first suggestion , i.e. the coolant mixture percentage . Next check thermostat , 1) is it working , ( simply put into a pan of boiling water by suspending from a piece of wire ) , 2) Is it installed correctly ? Next would water pump, not only is it functioning but is the gasket installed correctly ?

Fred H.

 

[Wayne_H]

Nonsense! Think about that for a while and then explain it to me.

Easy, the water does not spend enough time in the radiator to cool off.... It is an age old problem, old mechanics know it well.

Wayne

 

[Egon]

Easy, the water does not spend enough time in the radiator to cool off....

But doesn't it make more passes and all those little increments from each pass add up.

 

[Jim Thompson]

I'm certainly no expert on this, but, it seems to me that the question is one of efficiency. Certainly you have increased volume with no thermostat installed and the coolant would pass through the radiator more times but it would also pass through the engine more times thus gaining heat with each pass. Without the ability to efficiently dissipate the newly acquired heat, it seems to me that you could reasonably expect a net increase in heat with each pass - thus overheating.

I am well aware the people frequently removed the thermostat from engines in the 40s and 50s with seemingly no adverse effect. I also would not place a large wager, one way or the other, that at some point that they didn't encounter heating problems associated with that action. For those of us who remember those years, people also were known to run only water with no coolant. Knew a fellow with a couple of John Deere LAs who replaced the coolant with oil until he could replace a leaking head gasket.:laughing:

 

[user.69169]

Well now gents this here thread sure wnet both up and downriver, and the fellow who started it still has the problem.

I gotta figure the red hot description was a little off cause the pistons would sure as heck lock up before the block got that hot. Back when we run alcohol for antifreeze it was pretty dang common for an engine that hadn't run in a while to run hotter than hades when she first got going again, and every dang time it was cause of all the accumulation of rust that looked like cornflakes in all the water passages. Of course if a fellow didn't like his job and was fixin to quit he could clean out a few ashtrays in a choke & puke and put about 2 handfulls of filters that he busted open into the return hose and then start that truck up and cook an engine in a few miles. I've seen it done where the temperature gague didn't even go up cause there weren't no water around the sensor probe. I've seen guys who loaded them cigarette filters into the fuel filters too, and that is one mess.

Now if that was my engine first thing I'd do would be drain all the coolant and set it aside. Then I'd hook a garden hose up to the bottom engine drain and get water flowing just so it was trickling out the top of the radiator and start the engine up. Once you get her running you turn the hose off and let the engine get hot. You probably best clamp off the heater hoses when yo do this cause you don't want the crud plugging the heater core.
Once she gets hot you open the hose up and watch the crud & crap flow out top of the radiator. Yu do this a couple times and that engine got itself a clean cooling system.

Far as thermostats go, back when I started driving trucks didn't come with heaters. I had to pay an extra fifty dollars to get a heater in my Diamond T pickup back when I bought it. Them trucks didn't have thermostats cause they didn't need to get hot enough to heat the cab. Thermostats open and close at a set temperature to keep the engine running at that temperature probably some for efficiency and some for to have hot water going through the heater core.

 

[doall]

open station tractors don't have heaters, but they do have thermostats for a reason. I used to wrench for a living, take a thermostat out; sooner or later it'll run hot. The water is not cooling if it just flows straight through the radiator. The engine is way hotter that the radiator is cool in a short time.

 

[Egon]

If'n you got a big radiator wouldn't the distributed flow in the radiator be quite a bit slower than in a very small radiator?