I see that Polaris is still selling 2003 fan cooled snowmobiles. What are the advantages between fan and liquid cooled engines? Are there different applications for each? Why don't they just stick with one system?
The difference is a fan engine's cylinders have fins on them, then the whole engine is covered by a cowling and a fan is used to blow air across the fins cooling the engine. Fans generally produce less power due to the engine using more HP to turn the fan. Also the large cc engines don't cool as well with fans, because the more cc's the more heat. Fan engines also don't rev as high as liquids. Here's a pic of a fan cooled engine:
A liquid cooled engine looks a lot cleaner because the engine is cooled by water going through the actual block of the engine. This style of cooling costs a bit more, and requires more maintenence but it is more efficient. The coolant runs from the engine, to coolers, 2 the length of the tunnel and one at the front where snow contacts the warm heat exchangers, cooling the liquid for it's trip back to the engine. These engines also produce more power than an equally sized fan. Someone else will elaborate on this I'm sure, but it's what I've got. Here's a pic of a liquid cooled engine:
Liquid cooled engines have a tendency to perform more consistently than fan cooled engines. This is a result of a cooling system that is internal and controlled on the liquid vs. a dependence on air temperature for the fans. If you are going to do a lot of spring riding when temps could reach above freezing the performance that you receive from a liquid cooled is worth the extra money not to mention a probability of extra engine life.
The only advantage to a fan is that it is lighter and easier to mantain. Liquid cooled engines produce more power due to the fact that the cooling is better and more consistant. Therefore the tolerances inside the engine can be closer. Other benefits are: quieter, less vibration, more efficient, and longer wear life. The only reason they make fan cooled sleds is, it's alot cheaper.
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