* Leaking Sunroof Drain: This is a very common issue in many cars. The drains from the sunroof can become clogged with debris, preventing water from draining properly. The water then overflows and can seep into the cabin, often accumulating on the passenger side floor due to the car's structure. Check the sunroof drains for clogs.
* A/C Condensation: While usually not a significant amount, the A/C system produces condensation. If the drain line for the A/C evaporator is clogged, water can overflow and drip onto the floor. This is more likely to happen on the passenger side due to the location of the evaporator.
* Blocked or Leaking Heater Core: Less likely, but a leak in the heater core (located deep within the dash) can lead to coolant leaking onto the floor. This will usually smell sweet (like antifreeze). This is a more serious issue requiring professional attention.
* Weatherstripping: Poorly sealed doors or windows can allow water to seep into the car, especially during heavy rain. Inspect the weatherstripping around doors and windows for cracks or deterioration.
* Leaking Windshield: A crack or poorly sealed windshield can allow water to enter.
* Floor Pan Rust: Given the age of the car, rust in the floor pan is a possibility. Rust holes can allow water to enter from the undercarriage. This would usually require a closer inspection of the underside of the car.
* Sunroof Seal: A leak around the sunroof itself, not just the drains, can let water in.
Troubleshooting Steps:
1. Inspect the sunroof drains: Use a small hose or compressed air to clear any clogs.
2. Check the A/C drain: Locate the drain (usually under the passenger side of the dash) and make sure it's not blocked.
3. Look for water entry points: Inspect the car's exterior carefully during or after rain, looking for water dripping inside from anywhere – doors, windows, sunroof, windshield.
4. Check the carpet and insulation: Feel the carpet and insulation beneath it to determine if the water is coming from above (sunroof, A/C, windshield) or potentially from below (rust).
5. Smell the water: If it smells sweet, it's likely coolant from a heater core leak.
6. Run the A/C and Heater: Observe carefully to see if water leaks while running these systems.
If you're unable to pinpoint the source, it's best to take the car to a mechanic specializing in older vehicles. They have the experience and tools to diagnose and repair more complex leaks. A thorough inspection, possibly including pressure washing the undercarriage, will help locate the source of the leak definitively.
