How to clean the sunroof drains?

This blog will answer the following questions: how to clean the sunroof drains? What are the different types of sunroofs in cars? Why does the sunroof drain get clogged? What are the problems due to clogged sunroof drains?

How to clean the sunroof drains?

The procedure to clean the sunroof drains is described below:

  • Open the sunroof and clean the sunroof rails with a dry cloth.
  • Locate the sunroof drains, there are drains on both sides of the sunroof.
  • Use a long piece of wire or spring and carefully insert it into the drain hose.
  • Remove the pipe and pour some water into the drain to check if it drains the water.

The outlet of the sunroof drains is behind the front fender and alongside the B pillar. Therefore the wire or spring used to clean the drain should be the car’s height. The drain hoses are usually made up of rubber, if the wire is not inserted gently; it can dislocate or damage the hose.

Most sunroofs have 4 drain hoses located at the corners, the sunroof glass also has its rubber seal. Periodic cleaning of the sunroof rails is necessary even if the sunroof is not used frequently.

A can of compressed air can also be used to clean the sunroof drains and sunroof rails. If a compressed air hose is used to clean the drains, the pressure should not be too high as it can easily dislocate the hose from the sunroof frame.

Opening the sunroof is the easiest method to clean the sunroof drains as the other end is located behind the A and the B pillars of the car. If the drains are getting clogged frequently inspect the sunroof glass seal for cracks or damage. 

If the sunroof cannot be opened due to a faulty motor or jammed mechanism then removing the headliner is the only option to access the drain hose from inside the vehicle. Usually, the sunroof drains located in the front get clogged compared to the drains in the rear of the sunroof.

A vacuum cleaner can be also used to clean the drains, especially the drains on the back of the sunroof frame. When the sunroof is open the glass retracts on the back side, which makes inserting a wire into the rear drain more difficult.

After cleaning the sunroof drains, do not pour excessive amounts of water as the drains are designed to handle only small quantities. The rubber seal on the sunroof glass prevents the rainwater from entering the sunroof rails if the vehicle is parked outside.

What are the different types of sunroofs in cars?

The different types of sunroofs in the cars are:-

Sliding sunroof

The sliding sunroof consists of glass in the front half of the roof. When it is opened it either retracts inside the roof or pops out of the roof. The sunroof drains in this type of sunroof are bigger, they are located on all four sides.

There is only a single seal on the glass, hence the sunroof drains on the single-piece sliding sunroof system are more prone to getting clogged. The frame also takes up a lot of space on the roof.

The drain hoses of the sliding sunroof are connected to the inside of the sunroof rails. Hence when the drains are clogged, the water tends to saturate near the driver of the passenger footwell.

The damage caused due to the saturated water can be expensive to repair as electrical wiring harnesses and various control units are located on the floor of the vehicle. In some vehicles, the headliners can also get wet or the fabric of the headliners will be separated due to the water from the clogged drain.

Panoramic sunroof

Thus the type of sunroof design is commonly found in modern cars. The sunroof glass covers the entire roof. The retractable portion of the roof will open and slide back onto the outside of the vehicle.

The sunroof drains are also on all sides but there are channels in the bodywork of the car to drain the water instead of conventional hoses. These channels are present on the outside of the sunroof frame.

As the design of these drain channels is much narrower, it does not get clogged as easily as the sliding sunroof design. In order to clean the sunroof drains a panoramic sunroof, a simple vacuum cleaner or a can of compressed air is sufficient.

When the sunroof drain of this type of sunroof gets clogged, water cannot enter inside the vehicle as the frame of the sunroof is separated from the roof. There are also additional rubber seals on the sunroof glass and roof of the vehicle.

The outlet of the sunroof drains joins the water drain channels in the cowl top of the vehicle. Therefore, simply cleaning the cowl top can ensure the water from the sunroof drains down the cowl top.

Why does the sunroof drains get clogged?

The sunroof drains get clogged because of dirt and dry leaves getting stuck either on the inlet or the outlet of the drain hose. If the vehicle is driven frequently with the sunroof open and it is not maintained periodically then the dirt will accumulate in the sunroof rails.

The sunroof drains in the vehicle that is parked outside can also get clogged due to the dead leaves and foliage. It is necessary to check the front cowl top water baffle and remove the leaves to ensure that the water drains quickly.

After the sunroof drains are cleaned, the roof rails are also lubricated or greased. Remove the excess grease as it will attract dust and jam the roof mechanism. When the vehicle is serviced at an authorized workshop, the sunroof is cleaned and lubricated but it is a good practice to inspect the sunroof drains at least once a month.

What are the problems due to clogged sunroof drains?

The problems due to clogged sunroof drains are as follows:

  • Vehicle not starting – The rainwater leads to corrosion and excessive contact resistance between the potential distributors. The entire CAN network of the vehicle becomes inoperative and the vehicle cannot be started
  • Malfunction messages on the cluster – There can be multiple warning messages in the instrument cluster. The vehicle cockpit fuse box is located in the A-pillar which can get corroded due to the rainwater.
  • Damage to the floor carpet and roof liner – The accumulated water in the footwell gets absorbed by the floor carpets, and it is very difficult to dry the carpets and mats. The material of the roof liner also gets separated and starts to hang.


This blog explained the procedure to clean the sunroof drains of a car. As sunroof comes as standard in most cars, it is recommended to inspect the sunroof drains periodically. The sunroof can also make noise if it is not properly lubricated