This guide is about repairing your sunroof (sometimes called a moonroof). It applies to most vehicles fitted with a tilting glass sunroof. The same faults can apply to any vehicle, Renault, BMW, GM, Ford etc. The vehicle used is in this article is a Land Rover Discovery; (It has two sunroof’s – ‘Double trouble’!).
This type of sunroof comes in two halves, the top half containing the glass and opening mechanism, the bottom half acts as a drip tray (and may have the motor attached).
Note: If the drain tubes are working well you may only see faults in certain situations (the way the vehicle is parked, the amount of rain)? If the sunroof to roof seal has gone, then water may bypass the drip tray and the drain tubes and enter the vehicle directly through the roof seal.
Take note if your vehicle tends to leak more when parked in a particular position, as this may aid diagnosis of the fault?
This is where the two halves of the sunroof clamp the roof between them and form a sandwich-type seal.
The seal between the sunroof and the vehicle roof can dry out, allowing water to pass through.
Although the sunroof may show no visible faults, water can pass through the roof seal (the joint between the top of the sunroof and the car roof itself).
The drip tray (the bottom half of the sunroof) may not see large amounts of water unless there is a fault in the sunroof opening itself, or the drain tubes are blocked.
If you can see no visible fault and the amount of water entering the car via the roof started with a trickle and has been steadily increasing… The fault may well be the roof seal?
The drain tube fixing point may be a plastic moulding fixed to the sunroof ‘drip tray’ with a mastic. As with the sunroof seal, it can dry out, the seal can fail and water can leak onto the headlining.
In addition, the drain tube fixing point can:
If you can see no visible fault and the leak is in one particular area?
If the drip tray (the bottom half of the sunroof) is not storing water and the water is clearly running away, there may be a break in the drainage system.
These fix to the sunroof drain tube fixing points and are routed across the roof and down through the bodywork, and allow any water to drain through a hole in the underside of the vehicle onto the floor.
If the leak is in one particular area, or the drip tray (the bottom half of the sunroof) fills with water?
This is the seal between the sunroof and the glass. If there is a problem with the rubber seal there should be obvious visible signs:
You should see a visible fault, such as perished, shrunk or broken rubber. The drain tubes should carry away any water that gets past the rubber seal unless it is excessive, or the drain tubes are blocked or broken.
If someone has played around with the sunroof (e.g. the glass) and it is not fitted correctly, then this can lead to faults and then leaks.
Visual inspection for fit and finish?
You may be able to carry out some of the repairs without removing the headlining. But, if you’re going to go the whole hog, you may want to consider taking it out! This isn’t usually difficult but needs a fair amount of time and perseverance with removing lots of fixtures and fittings (and working out how it comes apart). Most roof linings should have some give and shouldn’t break or kink too easily if you are careful. You can also try to loosen part of it to gain access, e.g. one side, the front or back?
Note: Araldite (a two-part epoxy resin type glue) is very good for re-sealing and provides for a more rigid fixing, (beware; the drain tubes can break off if you try to remove the pipes! Araldite can also be used to fix these too!).
There are only two drain tubes fitted to these particular sunroofs. These are all towards the front end of the sunroof and operate to some extent independently.
The drain tubes exit the vehicle via the roof pillars (often called ‘A’, ‘B’ or ‘C’ posts). Water from the sunroof travels down these drain hoses and through a hole in the vehicle onto the road.
On the Land Rover Discovery (2 x sunroofs), the rear sun roof drain tubes exit near the rear lights. On the front sunroof, they disappear down the ‘A’ posts by the windscreen.
You need to ensure:
This is an easy item to change if you can get hold of one. It appears only to be sold as part of the sunroof assembly? However, I have seen the seal rubber sold individually on e-Bay.
Before you go down this route and spend hard earned cash, is it the seal causing the problem? It should only be the cause of the problem if it is dirty, damaged, or has an inherent defect? This should normally be visible.
The root cause of water ingress in a sunroof is often via:
To remove the seal, simply open the sun roof and carefully pull it out of the recess.
Note that you may see water on the seals from condensation running off the glass sunroof, or water running in from outside when the window opens.
If parts of the sunroof (such as the glass or frame) have not been fitted correctly, then this can lead to faults and then leaks.
All you can do is re-fit and repair as necassary.
You can test for leaks by pouring water into the drainage ‘drip trays’ and watching for water running out under the car. Note that:
To check the overall water integrity of the car (for the sunroof), you may need to leave the car parked in the rain for a day.
Try to replicate the previous fault conditions, such as parking the vehicle on a slight slope (nose up or nose down?), etc.