Car Radiator – Engine Damage, From Car Radiator Overheating

Car Radiator - Engine Damage, From Car Radiator Overheating
Car Radiator - Engine Damage, From Car Radiator Overheating

So, a car radiator is only one of the many parts, that make up your engine’s cooling system.

But, the car radiator is the most important part, as it disperses the biggest amount of heat. While, holding and storing your engine’s coolant.

Other parts include, a liquid coolant, water pump, hoses, a fan, a thermostat, heater core and coolant overflow tank.

So, a car radiator has three main parts, the core, the pressure cap (rad cap ), and the outlet/inlet tanks.

The Core

The core is the main section, with rows of narrow metal fins. This is where hot coolant, releases its heat and where the radiator cools it.

The Pressure Cap ( rad cap )

The pressure cap ( rad cap )seals the cooling system and ensures that it remains pressurized. This pressure is crucial, for the radiator to operate efficiently. Because, it keeps the coolant, from boiling and overflowing.

Outlet and Inlet Tanks

The outlet and inlet tanks, direct coolant to the radiator, after it has circulated through the engine. These tanks manage the liquid, when it is very hot.

Car Radiator Breakdown
Car Radiator Breakdown

Consequently, if any one part of the radiator, is not working properly, it affects the whole cooling system. Every engine out there today, should be operating within, a normal temperature range. Most of the time, this is going to be, around 195 to 220 degrees F.

One of the most important things you can do, for the cooling ability of your radiator is, simple maintenance. Because, excessive contaminants, on both the inside and outside of your radiator, can cause a severe drop in cooling efficiency. So, clean engine coolant in a sealed and pressurized car radiator, can efficiently transfer heat away from your engine.

Common Engine Cooling System
Common Engine Cooling System

So, a relatively constant operating temperature, is absolutely crucial. Also, for proper emission control, good fuel economy and performance. Consequently, a 50/50 mixture of water and antifreeze will boil at 225 degrees, if the radiator cap is open.

But, what do you need, to increase that boiling point.

You need a clean sealed cooling system, that holds pressure. Along with, a radiator cap rated at 15 psi. Because, this will raise the boiling point of a 50/50 coolant mixture, up to 265 degrees. However, if the mixture is raised to 70/30, the boiling point, goes up to 276 degrees.

Why Excessive Heat Kills Newer Engines

Firstly, the clearances in today’s engines are a lot smaller, than those in engines built in the 1970s and 1980s:

  • Piston to cylinder wall clearances, are much tighter, to reduce blow-by for lower emissions.
  • Valve stem to guide clearances, are tighter, to reduce oil consumption and emissions.
Aluminum Cylinder Heads
Aluminum Cylinder Heads

Many engines today, have aluminum cylinder heads. But, aluminum does not handle, higher than normal temperatures well, making it vulnerable to heat damage.

Consequences Of The Car Radiator Overheating The Engine

So, if the engine overheats, the first thing that will happen is, the engine will start to detonate.

Also, the engine will ping and start to lose power, under load. Usually, caused by the combination of heat and pressure, exceeding the octane rating of the fuel.

If the detonation problem persists, the hammer like blows may damage:

  • Pistons
  • Rings
  • Engine bearings
Damaged Piston Rings
Damaged Piston Rings

Overheating, can also cause pre-ignition. Because, hot spots develop inside the combustion chamber, that become a source of ignition for the fuel. As a result, the erratic combustion can cause detonation, as well as engine run on in older vehicles. Also, hot spots can burn holes, right through the top of pistons.

So, engine overheating can cause, a blown head gasket. Because, excessive heat makes aluminum swell, almost three times faster than cast iron.

The resulting stress, can distort and warp the head in certain areas like:

  • Like those between exhaust valves, in adjoining cylinders.
  • Also, areas that have restricted coolant flow, like the narrow area that, separates the cylinders.

The typical aluminum head expands the most in the middle, crushing the head gasket. As a result, causing a loss of torque, allowing coolant and combustion to leak.

Engine Damage From Car Radiator Overheating

Bent Valves From Car Radiator Failure
Bent Valves From Car Radiator Failure

So, if the coolant gets hot enough to boil, it may cause hoses or the car radiator to burst. Also, pistons may swell up and scuff or seize in their bores. Exhaust valve stems, may stick or scuff in their guides. This, in turn, may cause valves to hang open. As a result, damaging pistons, valves and other valvetrain components. Finally, if coolant gets into the crankcase, engine bearings will fail.

Engine overheating can be caused by anything that, decreases the cooling system’s ability to absorb, transport and dissipate heat.

Common Causes Are:

  • Low coolant level
  • Loss of coolant (through internal or external leaks)
  • Poor heat conductivity inside the engine, because of accumulated deposits in the water jackets
  • A defective thermostat, that doesn’t open
  • Poor airflow through the radiator
  • A slipping fan clutch
  • An inoperative, electric cooling fan
  • A collapsed, lower car radiator hose
  • An eroded or loose, water pump impeller
  • Even a defective radiator cap
Water Pump Failure
Water Pump Failure

So, heat always travels, away from an area of higher temperature, to an area of lower temperature. So, the only way to cool hot metal, is to keep it in constant contact, with a cooler liquid. Consequently, as soon as the flow stops, temperatures begin to rise. As a result, the engine starts to overheat. Now there is no way, to remove the heat from the coolant.

Flow Will Stop If:

  • The water pump fails
  • Your thermostat is not working
  • You have a loss of coolant replaced by air

Above all, the coolant needs a way to get rid of the heat it soaks up, while passing through the block and head.

So, the car radiator must be capable of doing its job, which requires the help of an efficient cooling fan. Finally, the thermostat must be doing its job, to keep the engine’s average temperature, within the normal range. So, if the thermostat fails to open, it will effectively block the flow of coolant and the engine will overheat.


Clogged Car Radiator
Clogged Car Radiator

So, most car owners don’t maintain their cooling systems, as well as they should. As a result, the most common problems car radiators fall prey to, is clogging and leaks. Dirt, bugs and debris, can block the airflow through the core. And, reduce the radiator’s ability to dissipate heat. Finally, internal corrosion and an accumulation of deposits, can also inhibit coolant flow and reduce cooling.

Thank You !