What is the Tunnel on a Snowmobile? [Repair & Cleaning Tips]

The tunnel on a snowmobile is part of the chassis. It looks like a giant galvanized steel gutter, just upside down. Besides its important structural function, it also plays many other roles. It houses the seat, rear bumper, snowflap, heat exchanger, rear light, foot rails, and so on.

If you want to learn more about snowmobile tunnels, this post is for you.

No fluff, no affiliate links, just the solid info you need!

What is the Tunnel on a Snowmobile?

Just like any other vehicle, snowmobiles have a chassis. It’s safe to say that it’s the biggest and most important part of the sled. This is because all other parts are mounted onto this big structural component! Additionally, the tunnel performs many other functions on a snowmobile. These are as follows:

  • Structural role
  • Protection
  • Plays a role in cooling
  • Houses many other main parts
  • Carries accessories and equipment
  • The VIN number is located on it

If you are wondering what a snowmobile chassis and tunnel look like, don’t miss this short video:

Now let’s move on and take a closer look at the main functions of the tunnel!

Structural Role

The tunnel on a snowmobile is part of the chassis, which is the main structural component of any sled.

One of the most important roles of the tunnel is that it provides solid connection points for the skid. This means the tunnel connects the track and the whole rear suspension system to the other parts of the snowmobile.


While you are riding your sled, the track constantly picks up and throws out snow, ice, dirt, rocks, debris, and who knows what else.

The huge advantage of the tunnel that is protects you and other parts of the sled. Without the tunnel, the track would have you and the whole sled covered in snow and debris in a really short time!

For more protection, sleds usually have a snowflap, which is mounted on the end of the tunnel. Thanks to this unit, the track doesn’t throw snow onto the others riding behind you on the trails!

Supports the Cooling System

On liquid-cooled snowmobiles, the heat exchanger can be found on the inside of the tunnel. When the track spins, it throws fresh snow onto this heat exchanger.

This snow won’t allow the heat exchanger to warm up, which is the key to keeping the engine cool.

The tunnel not only houses the exchanger, but it also helps direct the snow onto it. Without the tunnel, the snow would fly everywhere but not necessarily on the exchanger!

The other benefit of the snowflap is that it keeps even more snow in the tunnel. In other words, it makes the cooling system more effective.

Houses Many Other Parts

The other added benefit of the tunnel that it serves as an attachment point for many other parts. These are typically as follows:

  • Seat(s)
  • Foot rail (running board)
  • Rear bumper
  • Snowflap
  • Rear light

It’s safe to say that these parts can be found on the majority of stock snowmobiles.

Houses Accessories and Equipment

Beyond the basic parts, the tunnel offers space for many other accessories and equipment as well. The most popular snowmobile tunnel additions are as follows:

  • Passenger seat
  • Bags
  • Fuel cans
  • Tunnel racks
  • Ski/Snowmobile racks
  • Ice fishing accessories
  • Any other gear (shovel, avalanche kit, etc.)

We will take a closer look at all of these additions in the next chapter!

VIN Number

Finally, it’s also good to know that the VIN number can be found on the side of the tunnel. It is not only stamped into the material but also printed on a small label known as “tunnel VIN label.”

Snowmobile Tunnel Additions

Snowmobile Tunnel Supports

Snowmobile tunnel supports and tunnel braces are used to increase the strength of the tunnel.

Even if tunnels look very durable, they can bend if you are a big guy or ride with a passenger. The extra weight can overload the tunnel, which may result in structural damage. To avoid these issues, you may want to add some extra support on your sled.

Tunnel supports are virtually metal frames that embrace the outer sides of the tunnel. They come with a custom rear bumper in many cases.

Unlike supports, tunnel braces can be installed on the inside of the tunnel. This makes them completely invisible from the outside.

Their only drawbacks are the extra weight and their price tags of course, as these tunnel protectors cost around $100-$200 depending on the model.

If you can afford it, you can’t go wrong by installing one. They are like extra insurance on your sled!

Snowmobile Tunnel Protectors

Snowmobile tunnel protectors are must-have accessories if your track is studded.

This protector not only protects the tunnel but the heat exchanger as well. This is because on a bumpy ride the studs can bite into the heat exchanger causing costly damage!

Do you need a tunnel protector? Because of the aforementioned risks, if your track is studded, you definitely need a tunnel protector on your sled!

How do you install a snowmobile tunnel protector? Many tunnels feature rails to mount the tunnel protector on. You can simply slide the protectors onto these rails. If they are too tight, you can gently tap them into place with a rubber mallet. Here’s a video showing how to install a tunnel protector on a snowmobile:

These protectors are very useful additions to any studded sled, but they also have a main drawback.

If the ambient temperature is very low, the snow and ice build-up can build a “bridge” between the protectors. If this happens, this bridge blocks the snow and it can’t cool the heat exchanger anymore. Finally, it may result in overheating issues!

Snowmobile Tunnel Wrap

Installing tunnel wraps is an easy way to customize your sled. Simply put, snowmobile tunnel wraps are vinyl sheets that give your tunnel a unique look. They come in many different colors, but black is the most popular among sledders.

Besides the tunnels, full wrapping of sleds is quite common as well.

Snowmobile Tunnel Gas Can

There are many different tunnel gas cans on the market for snowmobiles. Manufacturers offer special connection systems to attach cans to the tunnel. These are for example the Ski-Doo’s LinQ system, and other manufacturers have their own systems.

If you don’t want to invest in these expensive special cans, you can strap virtually any type of regular can onto the tunnel.

Snowmobile Tunnel Bag

To store your extra gear on your sled you can choose from countless tunnel bags and boxes. Hard-shell tunnel boxes do a really good job in powder, as they keep your gear dry all day long.

One of the best-known box manufacturers is Powder Keg LLC., which markets its products under the brand names of Power Kegs and Fuel Kegs.

You can use these products independently or even in combination.

Snowmobile Tunnel Racks

Just like storage boxes, tunnel racks are also a great way to store your gear. They are commonly used for transporting ice fishing accessories, avalanche kits, shovels, and so on.

But if you want to carry more cargo with you, it’s very important that you not exceed the weight limit of the tunnel!

Snowmobile Tunnel Ski Racks

Snowmobile ski racks and snowboard racks are special units that accommodate your skis or boards. There are two main different types on the market. Some ski racks come as complete rack systems with the ski holder, while others can be mounted on the side of other regular tunnel racks.

It’s a much safer and easier way to transport skis than lugging them in the backpack!

How do You Paint a Snowmobile Tunnel?

You can easily paint your snowmobile tunnel if you follow these simple steps:

  1. Remove the tunnel or completely strip off other parts of the sled.
  2. Remove the deeper scratches with coarse grit.
  3. Sand the entire surface with 300-320-grit paper.
  4. Carefully clean the entire tunnel with wax and grease removal.
  5. Clean it with rubbing alcohol as well.
  6. Paint the tunnel with the appropriate type of paint.

Are you wondering which paints are best for painting a tunnel? As this part is made of aluminum, it’s not recommended that you use any type of regular paint. These would peel off within a very short time!

Experts recommend using special urethane paints like DuPont ChromaPremier. Other options could be high-quality automotive paint, which are recommended for aluminum surfaces.

Keep in mind that the key to a good paint job is in the preparation. Sand the surfaces until they are super-smooth and give them a thorough cleaning before painting.

Many claim that painting the tunnel is not worth the effort. It requires a lot of work, and a perfect result is unfortunately not guaranteed. Instead of painting, there are alternative solutions that are worth considering, such as:

  • Powder coating
  • Plastic dipping
  • Wrapping with vinyl
  • Polishing

Each of these is a proven method to tune up your tunnel! As polishing the tunnel is probably the most popular and easiest solution, let’s see how to do that!

How do You Polish a Snowmobile Tunnel?

You can polish the tunnel on your sled in seven simple steps:

  1. Thoroughly clean the tunnel (remove all grime and dirt for the surface).
  2. Remove all parts from the tunnel (seat, rack, bags, cans, light, etc.).
  3. Use an SOS pad to remove the scratches, or wet sand them with a 300-400-grit sandpaper.
  4. Clean the surface again.
  5. Apply some polishing compound, one that is specifically recommended for aluminum.
  6. Polish the tunnel with an electric drill and a polishing cone/ball.
  7. Finally, grab a microfibre cloth to remove all the remained polish compounds from the nooks.

How do You Clean a Snowmobile Tunnel?

Before polishing it’s recommended that you carefully clean the tunnel. Tunnels can be very dirty as they are usually covered with dirt and salt. You can clean a snowmobile tunnel in four easy steps:

  1. Clean the tunnel carefully with hot soapy water and a sponge to remove any build-up.
  2. Spray down the surface with some special snowmobile tunnel cleaner. Leave it on the surface for a couple of minutes.
  3. Give it a good scrub with a hand brush.
  4. Wipe the surface with a clean rag.

If your tunnel is pretty oxidized the only way to get back its original shine is by polishing. The promises made by special tunnel cleaners sound good, but they can’t beat the results you get from polishing!

How do You Straighten a Snowmobile Tunnel?

If you ride your sled off-trail there is always a risk of hitting a log and bending the tunnel. If this happens to the tunnel on your sled, you will want to how to fix it. Here’s how to straighten a snowmobile tunnel step-by-step!

  1. Remove everything from the tunnel like the rear bumper, light, rack, etc.
  2. Place a piece of wood under where it’s bent.
  3. Apply some pressure to the bent area.
  4. You can also carefully tap the aluminum back into place. Best practice is to use a rubber mallet or a piece of wood and a hammer.
  5. Once the parts are in position, you can add rivets to pull the pieces back together if needed.

You can find many other good tips and tricks in this tutorial video:

Beware that straightening the tunnel is no easy task. In some cases, it’s not even possible to manage it at home. Finally, it always depends on the location and extent of the deformation.

If your tunnel damage is significant, it’s recommended that you take it to a professional, or replace the entire tunnel.

To reduce the risks of damaging the tunnel, it makes sense to cut its end.

How do You Cut the Tunnel on a Snowmobile?

To cut the tunnel on your snowmobile you should first remove every part from your tunnel. Don’t forget the heat exchanger inside the tunnel! Then, draw the cut line on top of the tunnel. Make sure you measure it correctly, as you will have only one shot! You can cut the material with an electric saw.

Beware that on some sleds the heat exchanger is welded to the bottom of the tunnel. If your sled has a welded exchanger, be careful not to cut it in half!

Also, keep in mind that shortening the tunnel on your sled can lead to overheating issues on hard-packed surfaces.

How do You Extend a Snowmobile Tunnel?

Unlike shortening, adding an extension to your tunnel is a much more difficult job. This is because there are no “snowmobile tunnel extension kits” available on the market. This means that if you want to extend the tunnel on your snowmobile you will have to make the extension part yourself from scratch. Although it can be done with an aluminum sheet, you will need some tools and skills as well!

If you want to learn how to extend a snowmobile tunnel, we can recommend this video:

Snowmobile Tunnel Capacity

Snowmobile tunnel capacity is probably one of the most frequently overlooked specs. This is the reason why you see many bent tunnels!

Manufacturers recommend that you not strap heavy cargo on your tunnel. Snowmobile tunnel weight capacities vary by model and can be found in each sled’s manual, as well as on a sticker on the tunnel.

Keep in mind that too much weight can damage not only the tunnel but the suspension as well.

Thus, don’t exceed the tunnel’s weight limit!


The tunnels on snowmobiles are part of the chassis. Besides being one of the main structural components, the tunnel on your sled has many other roles, such as:

  • Protects you and other parts of your sled
  • Helps to keep the engine cool
  • Houses other parts and accessories
  • You can carry extra fuel or gear on it
  • The VIN number is also located on its side

As you can see, tunnels are considered one of the most important parts of a snowmobile, and for good reason!





Recent Content