As requested I will repeat the reply I gave on Sunday that was deleted!
Audi market a 'Special lubricant for sliding/tilting roofs' that you can order from your dealer. It is a 90g tube, Part no.G 000 450 02. it costs over £20.
Another product from VAG, made by Dow Corning in the States to sort out problems with the VW EOS roof leaks caused by seals drying out and loosing their suppleness is another Special Lubricant, 30 ml applicator bottle, Part no G 052 172 A1. It is recommended for application to the soft door seals on convertibles to maintain suppleness and their ability to keep out water. This I use on all my A2 door seals. cost is approx. £40. I bought mine from VW but it is also available from
www.gbrtech.co.uk as Dupont KRYTOX GPL105 lubricant. and was £46.20 in Dec 2013. It has an unlimited shelf life if kept sealed in original container after use.
Both of these products need to be used very sparingly and you will be wiping them off each year due to contamination with dust, fine sand etc before re-applying, otherwise you will have an effective 'grinding paste'.........a definite no no!
Using the OSS regularly when clean and lubricated helps to maintain its working condition. Common sense also helps too.
DO NOT OPERATE if you suspect it could be frozen or frost is imminent as you could strip cogs or break cables. Don't forget to also keep door glass clean and lubricated to reduce strain on electric motors and manual winders too.
My A2 was registered on 3/3/2002 and has no record of sunroof maintenance but as it was Audi Dealer maintained by the first lady owner for 6 years it probably was although not noted. The second lady owner didn't use an Audi dealer but the recommended services were done and noted. They were both very careful owners and the original carpets had extra Audi carpets and rubber ones too.
Present Mileage 117118
It goes without saying but I've always given my cars a service when bought s/h just to be sure. Replaced the Fuel filter over the weekend. Awkward with just rear wheels on ramps but fuel loss was minimal as SPIKE had posted. It was genuine Audi, appeared clean and when cut open, could have remained in situ, but peace of mind etc........
Forgot to mention. Get a 2mm cycle inner brake/gear cable to keep the OSS drainage channels free of debris They are on the four corners of the open OSS. Best to silver solder the wire end to prevent fraying and round it off. Twist is as you push it down gently while you pour warm water down too. If clear water will run out under the front wheel arches.If it binds it may be blocked with too much silicone when perhaps an aftermarket windscreen was fitted as mine was.
Water was backing up to the tup of the 'A' pillar flowing over into the passenger side from where it was distributed around pass. door seals inside the car over the cill, behind the footwell panel over the electronics and into the underfloor compartment. Fortunately the thick and carpet foam held it until all was removed when 10 SPONTEX Sponges( buy directmail order,) kept water at t bay until I could wring out every morning as necessary.
I discovered a temporary solution was to insert a cocktail stick between exterior 'A'frame pillar and the black closed cell foam that is attached to the windscreen to create a gap preventing the water from backing up the blocked passenger drainage channel....At least until I could get up to Stoke Audi to have a genuine new windscreen fitted under their supervision.
Result a bone dry A2.
The rear OSS drainage channels were OK as they drain round the hatchback but do rod them in case,........Enjoy!
