Coolant question

[Flibbie]

I understand the idea of a pressurized coolant system to raise the boiling point of water. What I don't understand is the reason/purpose of the thermostat.

I kind of get the idea on cars in a cold climate with a carb.

Can someone please explain why a thermostat is needed/desirable on a fuel injected warm climate car. My car is a Stalker with a supercharged 3800 Buick F.I. engine.

In heavy traffic, my temp gets to 200F, on a cool night at 55-60mph temp is 135F. By comparision my '03 Silverado temp is always 205F whether idling in 100F traffic or 80mph in 40F weather. Jim

[slomove]

Can someone please explain why a thermostat is needed/desirable on a fuel injected warm climate car. My car is a Stalker with a supercharged 3800 Buick F.I. engine.

 

I guess it is not exactly needed but somewhat desirable to accelerate heating the engine from cold and to keep the engine a bit warmer when cool outside or cruising with little throttle at relatively high speed. I suppose if you should live in Yuma or similar place you may not really need that. Not sure about Naples, Fl....... But then, thermostats are cheap.

[MHKflyer52]

The thermostat dose several things when installed it the system. As slomove has stated it does help get the engine up to operating temp by causing the water / coolant to heat up which causes the thermostat to open so the coolant can flow through the system, block, head, and intake manifold on some cars, radiator and water pump. It also provides a restriction in the system so that the coolant has time to be cooled while passing through the radiator.

When the thermostat is removed from the system the coolant does not have a restriction so if the radiator does not cause enough restriction then it does not have enough time to cool to keep it from getting above the critical boiling point and then over heat.

Most thermostats have a small hole in the base plate to let the coolant pass even when the thermostat is closed so that the water pump dose not cavatate or sucks a hose close which is sometimes a problem if the water pump is not getting enough coolant passage through it which will also cause the engine to overheat until the engine RPMs are reduced enough to allow the water pump to lose its vacuum and coolant to flow.

In some race applications were the engine is running at high RPMs for sustained times like during a road race the thermostat is removed for better coolant flow but a restrictor plate is placed where the thermostat goes to provide enough restriction of the coolant through the system so that it has enough time in the radiator to lose the heat but stay close to the max operating temp of the engines cooling system for the best performance but usually does not work very well when slow or in stop and go traffic such as normal street driving.

Just my thoughts but you might want to look at the temp range of the thermostat that is in your car and even test it to see if it is working correctly. If it is working correctly then I would look at the radiator to see if it is flowing correctly as a partial radiator block will also operate with the same you have described.

Hope this helps.

[powderbrake]

What I don't understand is the reason/purpose of the thermostat.

Can someone please explain why a thermostat is needed/desirable on a fuel injected warm climate car. Jim

 

I suggest that the thermostat is there to primarily maintain a fixed operating temperature so the computer and all the systems are operating at the point the designers intended. A 65 degree swing in temp of an engine is going to have an effect on its operation.

[SkinnyG]

You also want the engine to reach optimum temperature quickly for fuel economy, emissions and longevity reasons. Engine wear can be considerable when it is cold and clearances are not perfect, plus a warm engine helps to vapourize the fuel better. Raw fuel will wash oil off the cylinder walls which isn't really what you want.

 

G