Sunroof - Popping Noise When Opening in Sliding Mode
GROUP: 60NUMBER: 94-03
DATE: Nov 9, 1994
SUBJECT:
Sunroof Makes Popping Noise or Jams While Opening in Sliding Mode
MODEL(s):
Golf III /Jetta III / GTI /Jetta GLX From 1993 m.y.
File this Technical Bulletin in Repair Manual No.: W42 012 294 114
CONDITION
When opening the sunroof in the sliding mode, an abnormally loud popping noise may be heard just after the glass panel has dropped down in the rear to begin sliding rearward. The noise is sometimes accompanied by a slight jump in the glass panel, and in severe cases it may jam, refusing to move rearward.
This condition is due to a mis-alignment of the spring loaded locking pawl for the rear panel guide, in relation to the release hook which is located on the center guide (cable carrier).
PRODUCTION
Improved packing and assembly procedures to prevent damage to the locking pawl pivot pins.
SERVICE
Slide the sunroof headliner fully open, and pop off the plastic sunroof trim frame to expose the panel guides and locking pawls.
Open the sunroof slowly in the sliding mode, while observing the locking pawl (arrow 1), and the release hook (arrow 2).
The rearward sliding release hook must smoothly engage the locking pawl, riding over the top of it and tipping it down (arrow 3). This unlocks the rear cable guide, enabling it to slide on the track.
If the initial engagement of the release hook to the locking paw is marginal as shown here, the tip of the release hook will run up against the tip of the locking paw rather than smoothly running over the top of it. This causes the center guide to hesitate slightly until enough force is accumulated to "pop" the paw down, unlocking the rear guide and creating the abnormally loud popping noise.
A severe misalignment can actually cause the tip of the locking pawl to ride over the top of the release hook, preventing the guide from unlocking. This will jam the roof, preventing any rearward movement. Repeated attempts to open the sunroof may damage the rear guide or sunroof frame in this case.
To correct a marginal or moderately severe misalignment condition, you can replace the rubber O-ring on the rear tip (arrow 1) with one which has a larger outside diameter. In most cases, we recommend using a 2 mm wide piece sliced from a rubber diesel injector cap, part number 068 130 229A. This will drop the other end of the locking pawl down by about 3 mm when in the locked position.
If too large an O-ring is required to bring the pawl down to an acceptable level, it will prevent the locking tang from dropping down into the slot in the track (arrow 2), and the roof will not close. In this case, the rear guide assembly will have to be replaced.
CAUTION
Part numbers are for reference only. Always check with your Parts Department for the latest parts information