1. Defective Taillight Gaskets: Faulty gaskets around the taillights can allow water to seep into the boot. Inspect these gaskets for cracks or damage, and replace them if necessary.
2. Seal around Tailgate: Check the tailgate's upper seal for cracks, gaps, or damage that could allow water to enter the boot when it rains or during car washing.
3. Clogged Drain Channels: Blocked drainage channels designed to divert water away from the boot can lead to water accumulation and leaks. Locate these channels and ensure they're clear from debris or blockages.
4. Broken Boot Seals: Damaged rubber seals around the boot lid or damaged weather stripping can allow water to penetrate into the boot when it rains. Inspect the seals for cracks or tears and replace as needed.
5. Ventilation Holes: Your Vectra may have boot ventilation holes that, if blocked, can cause pressure buildup inside the boot and lead to water leaks during car washes or heavy rainfall. Check and ensure these holes are clear.
6. Missing Plugs: There may be missing or damaged rubber plugs or caps on the car's underside that facilitate drainage. Check the bottom of the boot and ensure these plugs are intact.
7. Window Seals: Check the condition of the rubber window seals around the boot. Over time, they may deteriorate and allow water to seep through.
8. Cracks in the Bodywork: If you notice water leaks only in certain areas of the boot, it could be a sign of cracks or damage in the car's bodywork, particularly around the boot's edges or seams.
If you're unsure about identifying or resolving the issue, it's best to take your Vectra to a reputable mechanic or auto repair shop for further inspection and repair.