Information on the polycarbonate roof on early R172 Models

What does this mean?
It means that the Vario-roof on early R172 Models is a composite Polycarbonate panel which is made from a number of polycarbonate sections which are effectively ‘glued’ together to form the front section of the retractable ‘Vario-roof’.
The issue with these roof panels is, that the laminated sections start to separate (delaminate) and allow water ingress into the cockpit when the vehicle either accelerates, brakes or corners – soaking the electronics, electrics, seats, carpets, floors and of course the occupants.

What Models are involved?
Early versions of the R172 SLK Models, fitted with Polycarbonate Roofs.

General Information on the issue?

It has been noted that this type of roof was only installed on a, comparatively small number of vehicles and was later changed for a Glass Roof** (see General Notes below) which obviously, doesn’t suffer from this delamination issue.

Information from the UK and around the world?

It has been reported on forums that in 2013, less than 2 years after the launch of the R172 Model, that there had already been issues with the Polycarbonate Roofs

Process of repair
Firstly, if your Polycarbonate roof is leaking; Contct your dealer and discuss with them.

What happens if the Dealership wants to Charge for the inspection? Generally, if the Dealership wants to charge for the inspection, that is up to the owner to decide if they wish to pay. If the Dealership still wish to charge, the owner is free to take it to another Dealership.

Prior to contacting a Dealership; Owners should carry out a ‘Pre-visit Inspection’!
Prior to taking the car in to a Dealership, owners should undertake some checks on the roof and its seals and identify that the water ingress is due to roof delamination and not just a seal failure or the seals drying out, etc.

• Treat the roof seals with something like Gummi Pflege to ensure the seals are soft and plumped up to enable them to seal.
• Qwners can undertake these tests and visually check if the inner and outer roof ’skins’ are starting to delaminate, (usually along the front edge of the roof), also check where the water is coming in, using these checks, will ascertain if it is the roof delaminating that is causing the water ingress or if the seals need attention.

Having undertaken these tests and checks?

• Book the car in and take it to an MB dealership for inspection.
• Follow the guidance above
• The dealership will inspect the condition of the roof panel and see if it is separating and should carry out the tests required
• The Dealership should then send their report back to MBCS UK who will, hopefully, approve the repair/replacement, .

General Notes:

** Glass Roof Panels – water ingress is also an issue with the Glass Roof Panels this does seem to, initially, be due to the roof seals, possibly drying out and shrinking or becoming hard and not sealing against the roof. Check the seals first and maybe use something like, Gummi Pflege to rejuvinate and lubricate the seals .