I wasn't sure where to post this, but since i have a honda i'll try here. Just wondering about dipping a hot engine in cold water. My Rancher is new (40 km, but i guess that doesn't matter). Can riding through icy water when the engine is at a normal operating temperature hurt the engine. You know, hot metal shrinks as it cools. So i would understand if damage could be done by this sudden submersion in icy water. But you can't help that around here this time of year!!

 

it won't hurt your motor at all, you may notice a slight loss of power though as it will cool your motor a little and the colder a motor is then the richer it will run. on a liquid cooled motor you would not notice this at all as the waterjackets would keep the engine operating at the same temperature in the water as it does out of the water. water will hurt your cooling fan though if it does come on while the fan is submerged, well actaully it won't hurt the fan, it will just blow the fuse.

 

never thought of the fan....too bad there's not a switch for the fan so it can be turned off before you hit the water....i still don't understand how a hot engine dipped in icy water doesn't crack or something!!...i know it doesn't 'cuase i do it all the time...but it still amazes me.

 

I agree I think the sudden shock from the icy water on the hot head would crack the head but I don't really know. Anybody

 

yeah i found out about the fan the hard way,lol, anyway my suzuki has a fan switch so i always make sure to shut it off now. i know that nobody here will believe this, but 40 degree water doesn't cool your engine anymore than 40 degree air. as a matter of fact air cools slightly better than water( i know it sounds impossible) this is part of the reason that an air to air intercooler is so much more efficent than an air to water intercooler. now you are prob thinking why do companys make water cooled engines; this is because watercooling keeps the engine temperature at a constant, therefore heating and expansion don't need to be worried about and engine tolerances can be made tighter. an aircooled engine will vary in temperature much more than a water cooled engine.

 

D@mn you would be needing to move alot of CFM to cool an engine. Why doesn't driving down the highway cool your engine off then?

 

but wouldn't a dip in 40 degree water cool the engine "QUICKER" than 40 degree air?...that's the reason i don't understand why it doesn't hurt an engine...i'm not disputing you because i do it all the time and it doesn't appear to hurt anything...i'm just trying to understand it...

 

lol, driving down the highway doesn't cool your motor, unless you have an old porshe or vw, because the motor in your car is watercooled and doesn't have cooling fins, also your car motor is encased by your hood, fenders and grill, so air isn't blowing directly on it.
greatcanadian, i know your not disputing me, i'm just having a hard time explaining it, basically heres the easiest way i know to explain/test that air has a (slightly) greater coefficent of cooling than water. next time you are riding in water(that is about the same temperature as the air) let your motor run for min or two in the water and then reach down and touch your motor, you will find that it is still very hot, although you may be tricked into thinking it is cooler as every part of your hand will be cold from the water except the part you are touching your engine with. also, this will be very hard to do as the water temp in a pond is only equal to the air temp usually during the summer months after the sun sets.

 

also to add to above, the cooling fins will feel cooler than in the air beucase they are no longer the primary heat exchanger so you will need to touch a part of your motor where there are no fins, close to the exhaust port would be a good place.

 

Water of a cool temprature that makes contact with a hot engine is what is known as "thermal shock".

The theory would be that it would crack the head or any other aluminum casting, however I have never heard of it actually happening.