Overheating (Engines)

The burning coolant smell in your 2003 Chevy 4x4 truck, despite no overheating or visible leaks, could indicate a few potential issues. It may be caused by a leaking head gasket, allowing coolant to escape into the combustion chamber, or a problem with the intake manifold gasket. Additionally, a malfunctioning heater core or a coolant line near the exhaust could also be to blame. It's advisable to have the vehicle inspected by a mechanic to accurately diagnose and resolve the issue.

Overheating in a 4G15 engine, even with a newly overhauled radiator, new water pump, and fresh engine oil, can be caused by several factors. Potential issues include air trapped in the cooling system, which can impede coolant circulation, or a malfunctioning thermostat that may not open properly. Additionally, blockages in the coolant passages or a faulty temperature sensor can also contribute to overheating. Lastly, inadequate coolant levels or a failing head gasket could lead to excessive heat buildup.

When your car's heater is on, hot coolant from the engine is diverted to the heater core to provide warmth to the cabin. If the engine is overheating, it could indicate issues such as low coolant levels, a malfunctioning thermostat, or a failing water pump. These conditions can prevent the cooling system from effectively regulating engine temperature, causing the engine to overheat even when the heater is active. Additionally, if the heater core becomes clogged, it can restrict coolant flow and exacerbate overheating.

Yes - if thermostat does not open allowing coolant flow The simple answer is yes. They can either fail open (engine never heats up or heats up slowly and temp fluctuates) or, more normally, closed (engine overheats). But before you condemn it completely, make sure the engine is cold, remove and inspect the 'stat for obvious signs of damage then place it carefully into a pan of near boiling water. After a few seconds a gap should appear between the centre an the outside rim. New stats are relatively cheap but it is essential when replacing that a good seal of the cooling system is made. To stop vapourisation and to keep the temperature down cooling systems work under pressure. It is worth checking for minor leaks / weeps and the proper action of the radiator / expansion bottle / filler cap. You don't say which vehicle it is but they all use smilar principles.

Not a good idea, you may and probably will crack and warp vital parts. Let it cool down on its own before even adding cold coolant into the system.