Engine coolant doesn’t last forever, and to ensure proper functioning of your coolant system, it should be replaced on a periodic basis. Continuing to run old coolant in the system can cause problems like overheating, loss of power, and possible engine damage. Although each machine is different (check your manufacturer’s guidelines), most experts recommend snowmobile coolant be changed at least every 3-5 years or 5,000 miles.
Often a simple change-out of fluid is adequate, but if you have not changed the coolant for a long time or the coolant box is dirty from the inside, the system would benefit from a coolant flush. For that, read my simple guide on ‘how to flush a snowmobile’s cooling system‘.
Changing snowmobile coolant is very simple and doesn’t require much expertise, just a few tools and some buckets (to collect the old coolant) will work. It is easy if followed step-by-step, and should only take an hour or so.
What you need to change snowmobile coolant:
- Fresh coolant. Although most automotive coolant mixtures will work in snowmobiles, I would recommend you use the snowmobile-specific coolant recommended by the manufacturer. This is usually sold as pre-mixed antifreeze diluted with water. If you decide to use straight antifreeze then you will also need distilled water to make a mixture.
- Buckets or any other container to collect the old coolant.
- Ratchet set
- Needle nose pliers for removing hose clamps.
- Funnel to fill flush fluid and/or coolant back into the snowmobile.
- Paper towels/rags to catch any spilled coolant.
- Screwdriver set (both flat and phillips head)
Step 1: Draining the old coolant from your snowmobile.
Draining the coolant is easy in most snowmobiles as there are bleeding and draining bolts to help out. The bleeding bolts are on the heat exchanger, which is located above the track and below the seat. You may need to removed the seat to access these.
You will also need to lift your snowmobile from the rear side to drain the coolant from the heat exchanger completely. To lift the snowmobile, you can either hoist it up with a come-along or winch mounted to the ceiling, or jack it up from below and support it safely.
There are two types of cooling systems in snowmobiles, one with the radiator and the other one is without the radiator. Most snowmobiles that have cooling systems do not have a radiator, but some heavy duty work-type machines have a radiator for enhanced cooling. Both cooling systems have different parts and different mechanisms to change the coolant. I have mentioned both methods, so follow up accordingly.
If your snowmobile does not have a radiator:
There is a valve connected to the main-hose (one going to the head gasket) of the cooling system. Open the valve cap. This is often a metal cap with a yellow or red sticker. Then, remove the drain bolt at the bottom of the coolant pump. You can refer to your snowmobile’s service manual to find the exact location of the drain and bleed bolts. Once the coolant starts pouring out, use a bucket to collect the dirty coolant and dispose of it properly.
You can also use the coolant hose, coming out of the head gasket, and going to the heat exchanger via the coolant pump. First, you will need to disconnect the hose, use the needle nose plier to remove the hose clamp, and put this hose in the container. It might be hard to put this hose in the bucket because there is limited space to do so. You can hold the bucket below the sled and aim with the hose to drain the coolant inside the container only. Additionally, you can use an air pump to blow air inside the fill valve and the air bleeding holes on the heat exchangers. This will help drain the system more thoroughly.
If your snowmobile has a radiator:
If your snowmobile has a radiator at the front, draining the coolant is quite simple. Put the bucket below the radiator’s drain bolt, so when you remove the drain bolt, the coolant will pour down into the bucket. Also, open the radiator cap to normalize the pressure inside so it drains properly. The coolant will start draining out. You can also blow some air in the radiator cap, so if there is any coolant left inside, it will drain out, but this is optional.
If your snowmobile does not have air bleeding holes:
Under the seat, you can find the two hoses connected to the heat exchanger. Disconnect both hoses and blow air in one of the hoses. This will help you to drain out any coolant left inside.
Coolant reservoir
The coolant in the reservoir bottle will not drain on its own because you have lifted your snowmobile from the back. You can remove the reservoir bottle and empty it in the bucket. Or you can disconnect the hose coming out of the reservoir and drain the coolant out that way.
Now that you have drained all the old coolant from your snowmobile, you should connect all the hoses and put back the hose-clamps. Make sure that all the hoses and clamps are properly-fitted, and no coolant is going to leak when you refill the cooling system.
Step 2: Dispose the old coolant according your state law.
The antifreeze used in snowmobiles is mostly ethylene-glycol (green color liquid), which is a toxic chemical. It is sweet, and there is a chance that your pet or kids might try to drink it. It is dangerous and can cause death. Always dispose of antifreeze according to state laws and guidelines.
Step 3: Fill the fresh coolant in your snowmobile.
Refilling the coolant in your snowmobile is far easier than draining it. Here are the steps in which I explain what coolant to choose for your snowmobile and how to refill it.
Choosing the right coolant/antifreeze for your snowmobile.
Always choose the right coolant/antifreeze for your snowmobile. It will not only help to cool your snowmobile’s engine efficiently but also increase the lifespan of the coolant. This way, you do not need to refill more frequently, and you ensure that the cooling system in your snowmobile is not going to fail and cause unwanted problems.
Remember, coolant is a mixture of antifreeze and water. Be sure to pay attention to whether you are purchasing pre-mixed coolant or straight antifreeze. Running undiluted antifreeze in your machine can cause serious problems.
Preparing your snowmobile for filling with fresh coolant.
Bring your snowmobile back down from the rear and lift it from the front (about 24 inches).
Start filling the coolant in your snowmobile.
First, fill the coolant in the rear heat exchanger. Remove one of its hoses and use it to fill the coolant while the other one remains connected. You will also need to remove the air bleeding bolts to help the coolant flow into the rear heat exchanger without any problems. Once the heat exchanger is full, connect the hose and clamp it down. Bolt down the air bleeding holes and make sure they are tightly fitted.
Now go to the front and use the same funnel to fill the coolant in the main valve of the cooling system. Pour the coolant in a thin stream, so air is not getting trapped, inside the coolant itself. Doing it slowly will let the air vent out of the fill valve easily.
By researching your snowmobile’s coolant system capacity you can better determine whether you are putting the proper amount of coolant in. For instance, if your Polaris Rush 600 needs a gallon of coolant, if coolant reaches the full mark after only half a gallon has been poured in, there’s a good chance that you didn’t drain the entire system, or – more likely – there is air trapped in some part of the system. That’s where the bleeding valves come in. Check your snowmobile’s service manual to determine the amount of coolant it requires.
It is common to have air when filling the new coolant. One hack I use to eliminate air out of the coolant is that I let the coolant bottle sit for some time, so all of the air inside will come on top. Not shaking the coolant bottle just before pouring it also eliminate most of the air pockets inside. Make sure all the hoses and clamps are tightly-fitted, and no coolant is leaking. Once done filling the coolant, the next step is to bleed the air out.
We will also need to fill the coolant in the reservoir coolant bottle after we are done burping the air out of our snowmobile’s cooling system.
Step 4 : Burp out the air bubbles out of your cooling system.
No matter how careful you are pouring the coolant in your snowmobile, some air is going to get trapped inside the cooling system of your snowmobile. Burping out the air (from your snowmobile’s cooling system) is very important because any air pockets left in the cooling system will cause extreme overheating, and you might end up damaging your gasket.
Burping out the air is very simple, but it requires patience.
Squeezing the coolant hoses to let the air out of your cooling system.
Start by squeezing the the two hoses simultaneously at the heat exchanger to burp out the air bubbles from it. It is the lowest part of your snowmobile now (as you have lifted it from the front), so as you are squeezing the hoses, the air pockets will break and escape from the heat exchanger.
As the air bubbles escape, the level of coolant decreases. Continue to add coolant, but avoid overfilling. Squeezing the hoses can cause the coolant to spill if the valve is full to the top. Once no more air is coming out and the coolant level does not drop, this means that you have successfully burped out all the air pockets out of the heat exchanger.
Now come towards the main coolant hose that is connected to the head gasket of the engine. Start squeezing this hose to let out all the air that is trapped inside the head gasket. Fill the coolant as required. If your snowmobile also has a radiator, then one end of the main-hose is connected to the radiator, and the other end of it is connected to the head gasket. You will need to squeeze these hoses to eliminate any trapped-air from the radiator. The coolant level will go down again in the main valve so add more coolant to it.
Congratulations! You have successfully removed most of the air pockets from the cooling system of your snowmobile. Now close the filler cap and slowly put down your snowmobile and remove the hoist or lift supports.
Starting the engine to remove air bubbles from the coolant pump
There is a chance that some air is still trapped inside the cooling system, especially in the coolant pump, but do not worry about it. Remove the filler cap and put a paper towel around it to catch any accidental leaks. Start your snowmobile and let it run for a few minutes. This will circulate the coolant inside the snowmobile and help to remove any trapped air bubbles from the coolant pump.
Now, shut off your snowmobile’s engine and let it cool down for several minutes. We are going to do this because the coolant expands when heated, and letting it cool down will allow us to fill the required coolant. Now fill the main valve with the coolant and close it tightly. Now we have successfully removed air bubbles from the cooling system.
Step 5: Filling the coolant reservoir.
This step is really simple. Open the coolant reservoir cap and fill the coolant up to the “cold fill” mark.
Some things to look for after you have changed the coolant in your snowmobile
Go for a ride on your snowmobile and check if everything is working as it should. When the engine has cooled down, open the valve cap and check if the coolant level is still enough. There is a rare chance that the coolant level will decrease, but it is good to check once after a ride.
If the coolant level has gone down, then fill the coolant again. If you have filled more than the required coolant or the coolant level keeps dropping, there might be a leak in your cooling system. And you will need to fix that as soon as possible.
Also, verify that the heat exchangers are warm. A heat exchanger or return hose that is significantly cooler than the other heat exchanger or the hose is a clear indication of trapped air within the cooling system.
How often should you change coolant in your snowmobile?
Most snowmobile manufacturers recommend changing the coolant every 2-years, while many snowmobile experts say 3-5 years is okay. When it comes to things like this, I always prefer to look into the service manual of my (or any other) snowmobile.
An overheating snowmobile means that you need to replace the coolant, but here are some other overlooked symptoms:
If you run your sled hard for the whole snowmobiling season and then it sits for all the summer, you must check the coolant before riding it the next season. In older snowmobiles (more than 5-years old), it is important to keep an eye on the coolant because it might cause rust and acidic build up inside the cooling system of your snowmobile and hurt its performance.
If you have bought a used snowmobile, you do not know what kind of coolant the previous owner has used or how frequently it was changed. Especially in power sport engines, when the engine runs on higher RPMs, there is a higher chance of overheating due to old or dirty coolant. It is always a good idea to super flush a coolant after you have bought a used snowmobile or if your snowmobile is older than 5-years.
In Conclusion…
Changing your snowmobile’s coolant is not a complicated job. It requires just some basic tools, and you can do it in your garage. Doing it yourself will teach you a lot about your snowmobile, and will save you around $100, if not more. So why take it to the shop and pay big money when you can do it yourself?
And remember to dispose of the coolant properly according to state or local laws.
Have fun out there!