Pressurized Cooling system on the 850??

christopher · Dec 7, 2016

Odd question.

This evening I was prepping my 3 sleds for our weekend at Togwotee for my son's bachelor party. I noticed that all three sleds were VERY low on coolent, so I opened the cap on STONE COLD sleds, and the coolant spewed everywhere, making quite the mess..

Once it settled down, the level in the tank ROSE by a good inch or so and rather than being well below the "COLD FULL LEVEL" it was now Above it.

Is this normal??

christopher · Dec 7, 2016

Before opening

After opening

MountainJunkie · Dec 7, 2016

Hi Chris,

Neither of our sleds had that much pressure when we opened them up cold. My wife's sled came with low coolant as well but when I opened the cap the first time it only rose half an inch.

I believe it's bulletin #5 on these that addresses a possible issue with an air bubble somewhere in the system (I think it was the heat exchanger)

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powdermuncher · Dec 7, 2016

Checked on mine and the same thing , also I opened it slow expecting it and made no mess-- she burps from right above the middle ring to just over full .

Have 2 good rides on here everything working well and the coolant level has not changed since I took delivery.

My guess as unusual as that seems is that it is a standard for the type.

maybe some other guys can check theres as well mine is in the shop at around 18 degrees Celsius.

jph3 · Dec 7, 2016

Mine did the same. When I first brought it back to the garage I noticed ho low it was... as soon as I opened it it was over full.

sledhead_24_7 · Dec 7, 2016

Doos have done that since 2008. They hold pressure well. If you open the cap too fast it blows out everywhere.

KevO · Dec 7, 2016

Mine came with about .25" of coolant in the reservoir. I filled to the line and let the sled sit on an incline for a while, anything else i should worry about as far as cooling?

Chadly · Dec 7, 2016

Are you sure it doesn't have anything to do with the elevation change?

Devilmanak · Dec 7, 2016

Why did you take a before picture for a coolant level check? Anticipating a problem?
Anyway. When I pdi-ed one of mine, I was told by the dealer that they had level issues, so I grabbed a bottle of coolant to top it off. Little low. After a 75 mile ride, it looked low, so I pulled the cap off and it spewed. It was fine. Pressure in the system means hoses that are flexible will be larger than should be when cold. No issue.

MountainJunkie · Dec 7, 2016

Devilmanak said:
Why did you take a before picture for a coolant level check? Anticipating a problem?
Anyway. When I pdi-ed one of mine, I was told by the dealer that they had level issues, so I grabbed a bottle of coolant to top it off. Little low. After a 75 mile ride, it looked low, so I pulled the cap off and it spewed. It was fine. Pressure in the system means hoses that are flexible will be larger than should be when cold. No issue.

I live an hour out of town and was due to head the opposite direction of town the following day with the sleds. I didn't have any coolant for it so I sent my salesman the picture to see what his thoughts were.

I wound up elevating the machine and pulled an air bubble out so we delayed the trip for a weekend and hit the dealership on Monday for some coolant.

powdermuncher · Dec 8, 2016

As long as you see coolant in the bottle you are save the cooling system is full the bottle is extra. My XM liked it below the middle when cold and stayed there for 2 seasons without any loss. One of the other riders toped his up to the midd level each ride and it blew it out every time.
Once he stopped toping it up his level stayed roughly the same as mine.
Long story short if you see coolant in the tank don't mess with it.
On the G4 I would venture a Guess that the tunnel heat exchanger combo may have something to do with the pressure. Lots of surface area there. Aluminium shrinks a lot as it cools down.

MountainJunkie · Dec 8, 2016

powdermuncher said:
As long as you see coolant in the bottle you are save the cooling system is full the bottle is extra. My XM liked it below the middle when cold and stayed there for 2 seasons without any loss. One of the other riders toped his up to the midd level each ride and it blew it out every time.
Once he stopped toping it up his level stayed roughly the same as mine.
Long story short if you see coolant in the tank don't mess with it.
On the G4 I would venture a Guess that the tunnel heat exchanger combo may have something to do with the pressure. Lots of surface area there. Aluminium shrinks a lot as it cools down.

My wife's sled drained the tank to basically the very bottom when we elevated it after that picture. Hers had one of the air bubbles mentioned by BRP recently but we got our summits before the low coolant bulletin.

I'm sure if you ask Rick he will tell you I was annoyingly picky about the sled to an unreasonable degree lol...

christopher · Dec 8, 2016

Devilmanak said:
Why did you take a before picture for a coolant level check? Anticipating a problem?

Anyway. When I pdi-ed one of mine, I was told by the dealer that they had level issues, so I grabbed a bottle of coolant to top it off. Little low. After a 75 mile ride, it looked low, so I pulled the cap off and it spewed. It was fine. Pressure in the system means hoses that are flexible will be larger than should be when cold. No issue.

Nope.
I have THREE sleds.
So the picture is of sled #2 when I wanted to document that this wasn't my imagination after it happening on sled #1

Illinoispowder · Dec 8, 2016

Coolant

I've owned 3 800 etec sleds, and all have been like this. These machines somehow hold pressure for an entire off season I've witnessed.

jos · Dec 8, 2016

Yes, coming from Arctic I was worried about this low level of coola t rather often, but somehow thats just a Doo thing, same on my XM.

Andystoy · Dec 8, 2016

If the sled is cold when the cap is loosened and than removed no antifreeze should shoot out if the sled was filled to the cold mark. If coolant shoots out there is air in the system that has been compressed and shoots out antifreeze when the cap is loosened.
Raise the front of the sled on a ramp and start and stop the sled several times, this should burp the air out and you will see a drop in coolant level, fill to the cold mark again and you should be good to go.
Most automotive systems have an air bleeder screw on top of the engine to allow you to bleed off the air as the system is filled with coolant, the sled does not have this. JMO

Illinoispowder · Dec 8, 2016

Coolant

It isn't air shooting out, it's coolant! Any perfectly burped automotive system will do the same if you release the cap under pressure. The etecs just do an excellent job of holding pressure for a long period of time.

Andystoy · Dec 8, 2016

A cooling system that was filled cold and has no air should not have any pressure to release when it has cooled back to original temperature. The reason a cooling system shoots out coolant when the cap is opened is that the air bubble is compressed as the engine comes to temperature when the cap is opened the air expands displacing the coolant.
If a pressurized cooling system has pressure trapped when cool there may be an engine problem such as a leaking head gasket, porous head or block etc. The bottle is an expansion chamber which allows the coolant to expand when warmed and return back to normal volume without losing coolant from the system. The cap has a pressure rating that opens if the pressure is exceeded and if the bottle is full will release antifreeze to the outside. The cooling system can be pressure tested if something abnormal is suspected?JMO

Illinoispowder · Dec 8, 2016

Re

Andystoy said:
A cooling system that was filled cold and has no air should not have any pressure to release when it has cooled back to original temperature. The reason a cooling system shoots out coolant when the cap is opened is that the air bubble is compressed as the engine comes to temperature when the cap is opened the air expands displacing the coolant.
If a pressurized cooling system has pressure trapped when cool there may be an engine problem such as a leaking head gasket, porous head or block etc. The bottle is an expansion chamber which allows the coolant to expand when warmed and return back to normal volume without losing coolant from the system. The cap has a pressure rating that opens if the pressure is exceeded and if the bottle is full will release antifreeze to the outside. The cooling system can be pressure tested if something abnormal is suspected?JMO

an automotive system has a "coolant reservoir" not an "expansion chamber" like the etec. The automotive radiator caps have vent holes above the rubber seals to allow coolant back into the radiator after it cools. The etec system is sealed and doesn't allow this. Once the coolant in the etec expands from heat it can't depressurize due to vacuum that would be created.

Andystoy · Dec 8, 2016

Pressurized Cooling system on the 850?? Reply to Thread

The older automotive systems had the coolant reservoir you describe with a cap vented to the atmosphere connected with a black hose to allow for expansion or recovery of fluid and was controlled by the radiator cap that was on the rad. Todays GM systems are the same as skidoo with no radiator cap on the radiator; the cap is on the coolant bottle which is pressurized when hot and returns to near zero when cold. (See warning label on cap)
The coolant expands and contracts according to its coefficient of expansion which is quite linear with regards to temperature so no residual pressure will be in the system if the system was filled at a certain temperature, than run where it expands and cools to the same volume as it was filled(no trapped pressure). If air is present in the system (in the heat exchanger) it responds to the gas law and is much more sensitive to temperature and pressure with regards to its volume.
The skidoo reservoir/expansion chamber/white bottle has a rad cap on it and it will open at a predetermined pressure (15 psi?) to prevent the system from over pressuring and blowing off the hoses.

Pressurized Cooling system on the 850??

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