What is difference between air cooled & water cooled engine?
Which is better? What is the advantage and disadvantage of air and water cooed engine?
- more slackLv 61 decade agoFavorite Answer
Air cooling uses airflow directed at fins on the cylinders and heads is the cooling medium: heat is transferred directly to the air. The air comes either by natural convection (e.g., a motorcycle) or by forced air (e.g., air-cooled VW or Porsche engine.)
Water cooled engines circulate coolant around the heads + cylinders though a surrounding water jacket, and use a separate high-efficiency radiator for the final heat exchange to the air. (Marine engines are a bit different - they use the surrounding water instead, either directly or though a water-to-water heat exchanger.)
Air-cooled engines are simpler, lighter and easier to maintain as they don't have the 'wet' cooling system elements. They excel in cold climates where coolant freezing can be a problem. However, air cooling is less efficient due to the low heat capacity of air so these engines suffer from hot spots which reduces power, increases emissions and shortens their life.
Air-cooled engines are also considerably noisier - both from the engine directly and also from the air blower cooling fan if used.
Water-cooled engines take advantage of water's high heat capacity to efficiently carry away the heat. So they offer the best control over temperature allowing for more aggressive / efficient tuning and optimal head design. While they have increased near-term maintenance costs (coolant, water pump, hoses, etc.) they make up for it in a longer-lived engine core (longer time between overhaul.)
Water-cooled engines are also quieter due to the insulating properties of the water jacket and the lessened airflow requirement.
Water cooling also permits more flexibility in engine architecture and installation since there isn't a need to duct cooling air directly to the cylinders.
- Anonymous1 decade ago
An air cooled engine is cooled by air running over the physical engine.
A water cooled engine is cooled by water that runs through the engine (absorbs the heat), the water is then cooled in a radiator which has air flowing through it.
Truth be told, both are effective, but water cooled engines are much more suited to stop and go traffic, and generally will cool better all around.
- Mike1942fLv 71 decade ago
A water cooled engine can be buried inside a car body, building, or otherwise be out of the way as long as the radiator can get air flow, usually by a fan or vehicle movement or both.
An air cooled engine must have fins to transfer heat and the housing must provide for air flow across the fins - design complication and more air resistance. But much lighter in weight, both without the liquid and the radiator, but also without the thick metal needed to house the coolant passages in the engine.
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- oxymandiaLv 61 decade ago
Water cooled, the coolant is almost always inside the engine; air cooled, it's outside.
Air cooled engines are lighter, but need a lot of air moving across them to get reasonable thermal transfer. This means either a big fan, or using the engine in something like a fast boat or airplane. Air-cooling it very poor in an engine that sits still.
- DebraLv 44 years ago
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Water cool engines have water jackets around the cylinder wall that flow to a radiator that keeps the engine cool. Air cool engines have a fan and sometimes have have finned cylinders to remove heat. Diesels don't get that hot since they run at a lower RPM. Diesels also run better when they are very warm since they don't have sparkplugs to combust the fuel mixture.
- 1 decade ago
for what application? Water cooled engines are going to be heaver but don't over heat as easy.
- 5 years ago
iti s lightier than water cooled enginr
- 1 decade ago