Cooling system workings……..

[ferniesnow]

Okay, I'm not really mechanically versed. So take me to school on the cooling system.

The cooling system is under pressure and the coolant flows on demand from a thermostat. First question, does the coolant flow through the reservoir? Second question, does the over flow line coming out of the reservoir have a valve on it that opens and closes with pressure build up? Third question, how is the computer involved in this scenario? Does it sense a drop in pressure and shut down the engine?

Now if the reservoir bottle breaks and drains what happens to the coolant in the "system"? Is it circulated or just pumped out the break in the reservoir bottle?

Just trying to figure out if there is an "out in the backcountry" solution other than towing the sled.

 

[moyiesledhead]

Cooling systems are pressurized to help keep the coolant from flashing off to steam. Doesn't normally flow "through" the reservoir. The overflow does in effect have a valve, that being the cap. Pressure lifts the spring in the cap and uncovers the outlet to the overflow to relieve excess pressure. What the computer is doing on your sled I have no idea. I haven't seen the G4 coolant bottle, but if it breaks I suspect you're going to lose coolant. At the very least it'll be easier to overheat being un-pressurized.

Edit: Now that I've seen one it looks like the coolant might indeed be flowing through your coolant bottle. Theory of operation is still the same though. Sure looks like your gonna lose coolant if that puppy breaks.

 

[Lund]

Okay, I'm not really mechanically versed. So take me to school on the cooling system.

The cooling system is under pressure and the coolant flows on demand from a thermostat. First question, does the coolant flow through the reservoir? Second question, does the over flow line coming out of the reservoir have a valve on it that opens and closes with pressure build up? Third question, how is the computer involved in this scenario? Does it sense a drop in pressure and shut down the engine?

Now if the reservoir bottle breaks and drains what happens to the coolant in the "system"? Is it circulated or just pumped out the break in the reservoir bottle?

Just trying to figure out if there is an "out in the backcountry" solution other than towing the sled.

The cooling system used in your sled and all other sleds out there that are within 10 years old use what is called a "closed loop system"
Starting at the water pump, when the motor is cold the flow will circulate from the pump through a bypass hose or port back to the engine block and around it circulates. As the temp goes up at the thermostat that will be located generally at the bypass, it will start to open thus allowing flow to enter the coolant bottle. The coolant bottle in the system (close loop) is not an overflow bottle but is an expansion chamber as the coolant expands when heated and contracts when cooling. An over flow bottle is not installed inline in a cooling system but separate.
The flow once entering the coolant bottle now will flow into the heat exchanger then back to the engine entering the head and not the block. It will flow down through the block back to pump. And around we go.
To answer your question's, YES, coolant has to flow through reservoir once the motor is up to temperature.
No, the over flow line has no valve in it. All system pressures is completely regulated by the pressure cap (rad cap, not proper lingo for this sled, no rad in it)
The over flow line is just there for the purpose of dumping coolant should it be over filled. If over filled the system will over pressurize because there is not enough room to allow for expansion.
Yes your computer is linked into the system via a sensor mounted near the thermostat. You might even find 2 sensors, one for a dummy light or buzzer. The other ecu coolant sensor. Being your sled is EFI and timing is important to the performance of the sled, the ecu has to have info from the motor such as temp to set fuel richness and timing when cold and hot......or it would run like a sack of poop. This allows for a consistent running motor.

If the bottle breaks in the hills or riding you are FUBAR.

OK hears the nasty thing about cooling system's, while there is coolant in the system all sensors will operate, BUT, if the case of losing the coolant with out knowing, there will not be any warnings as the sensors WILL NOT SENSE a problem once coolant is gone. The sensor REQUIRE the coolant to work.
In the automotive world they use a float system, should the coolant be lost the float set off a light....There you have it Douge

 

[arff]

Always get all of the air out of a closed cooling system. The sensors don't read air in the system and can trick a person on the actually temperature.

Running antifreeze water mixture and a pressure cap allows the system to increase the boiling point.




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[Bnorth]

Always get all of the air out of a closed cooling system. The sensors don't read air in the system and can trick a person on the actually temperature.

Running antifreeze water mixture and a pressure cap allows the system to increase the boiling point.




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This is an important point. If you had a coolant leak and didn't notice it the sled would operate like normal and say the temperature is OK when really it is overheating since there is no coolant on the sensors and they cannot measure air temp. So say you put a hole in the back of the cooler and didn't notice you could pump nearly all the coolant out and overheat without any warning coming on until the motor squeaks.

 

[Caper11]

I carry a roll of high voltage splicing tape and super 88 electrical tape. Ive got sleds out of the backcountry and stopped coolant hose leaks on trucks with wrapping this around the hose. Just leave the cap loose so it wont pressure up. I think this will also help if the plug breaks off the coolant bottle as long as there is not a massive hole.

Another bandaid would be to cut the lines off the broken tank and plug the end of the lines with the proper sized bolts and hose clamps. If a person choses to run the sled without modding the coolant tank than having the supplies and tools to get the sled out would be advisable.


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[ferniesnow]

I carry a roll of high voltage splicing tape and super 88 electrical tape. Ive got sleds out of the backcountry and stopped coolant hose leaks on trucks with wrapping this around the hose. Just leave the cap loose so it wont pressure up. I think this will also help if the plug breaks off the coolant bottle as long as there is not a massive hole.

Another bandaid would be to cut the lines off the broken tank and plug the end of the lines with the proper sized bolts and hose clamps. If a person choses to run the sled without modding the coolant tank than having the supplies and tools to get the sled out would be advisable.


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Along with the questions that I asked about the theoretical aspect of the cooling system, that was the other important one. Thanks for that Matt.

 

[Caper11]

Along with the questions that I asked about the theoretical aspect of the cooling system, that was the other important one. Thanks for that Mark.

Now that i thought about it, I think I should stick some bolts and hose clamps in my backpack just in case for a 850 that will be in my group this weekend.


There will be coolant loss in a tank breakage but if the leak is caught quick enough, I believe a repair can be made and the sled can be driven out under its own power.

Matt


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[ferniesnow]

Now that i thought about it, I think I should stick some bolts and hose clamps in my backpack just in case for a 850 that will be in my group this weekend.


There will be coolant loss in a tank breakage but if the leak is caught quick enough, I believe a repair can be made and the sled can be driven out under its own power.

Matt


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Thanks Matt. Don't know where I got the Mark from?????

Yes, I was thinking that if one is in a situation and lost coolant, a fire could always be made, snow melted, and water could be used in a pinch. I have had to do that years ago but the reservoir wasn't broken. The cap came loose for some reason. The bolts and clamps are a great idea.

 

[greenthumb]

I carry a roll of high voltage splicing tape and super 88 electrical tape.

Super 88 FTW!
I will never use cheap pvc tape again, but at $6 bucks a roll, I'm sure glad we buy it by the box at work!