* Sunroof Drain: A clogged or disconnected sunroof drain tube is a very common culprit. These tubes are designed to carry water away from the sunroof, and if blocked, water can overflow and run into the cabin. The driver's side is often affected because the slope of the car directs water that way.
* Windshield Seal: A leak in the windshield seal, particularly around the lower corners on the driver's side, is another frequent cause. Over time, the seal can deteriorate, allowing water to seep in.
* Door Seals: Similar to the windshield, worn or damaged door seals (especially the driver's side door) can allow water to enter, particularly during heavy rain or when driving through puddles.
* A/C Condensation Drain: The drain for the air conditioning system is usually located near the passenger side, but a blockage could cause backup and overflow to the driver's side. This is less likely to be a constant leak.
* Floor Pan Holes/Rust: Rust or holes in the floor pan itself, especially in older vehicles, can allow water to enter directly. This is more common in areas prone to corrosion.
* Blocked Drain in the HVAC System: Similar to the A/C drain, a blockage in the ventilation system can cause water to build up and enter the cabin.
Troubleshooting Steps:
1. Check the Sunroof: Inspect the sunroof drain tubes (usually located at the corners of the sunroof). Try to clear any blockages with compressed air or a small, flexible wire.
2. Inspect the Windshield Seal: Carefully examine the windshield seal for any cracks or gaps.
3. Check the Door Seals: Inspect the driver's side door seals for any damage or deterioration.
4. Look for Rust or Holes: Check the floor pan on the driver's side for rust or holes, especially around the seams.
5. Test the A/C Drainage: Run the A/C and see where the condensation drains. If blocked, you might find a puddle under the car.
If you can't find the source yourself, it's best to take your Pontiac to a mechanic. They have the experience and tools to diagnose and repair the leak effectively. Remember to point out the specific location of the water accumulation (driver's side floor) to help them focus their efforts.
