A water leak inside a vehicle can be difficult to diagnose because the liquid appearing on the floor is not always coming from an obvious source.
That was the situation with this 2016 Ford Ranger, where the owner noticed clear water pooling on the passenger-side front floor after spending extended periods in the vehicle with the engine idling and the air conditioning running on high.
The vehicle was brought to our workshop so we could identify where the water was coming from and determine why it was getting into the cabin.
The Problem: Water Pooling on the Passenger-Side Floor
The owner works in the construction trade and regularly spends extended periods sitting in the vehicle with the engine running and the A/C on high while preparing quotes for customers.
After these longer periods, he noticed clear water pooling on the passenger-side front floor.
Because water inside the cabin can potentially come from different sources, we needed to determine whether the problem was related to the vehicle’s cooling system or the air conditioning system.
Checking for a Coolant Leak
Our first step was to check the cooling system for coolant loss.
We also pressure tested the cooling system, but found no evidence of coolant loss.
This helped rule out a cooling-system leak as the source of the liquid entering the cabin.
Rather than relying on the appearance or colour of the liquid alone, the cooling system was properly checked and pressure tested as part of the diagnosis.
Investigating the Air Conditioning System
With no coolant loss found, we then investigated whether the water could be related to A/C condensation.
When the air conditioning system is operating, condensation is produced within the A/C system. In this case, we needed to determine why that condensation was getting into the cabin rather than exiting correctly.
The investigation led us to the A/C box and the way condensation exits through the firewall.
Finding the Source of the Cabin Water Leak
After an extensive diagnostic procedure, we decided to remove the complete dashboard assembly, followed by the A/C box, so we could inspect the area for a possible condensation leak.
We found that condensation exits from the A/C box through a small outlet that protrudes through the firewall.
We also found the cause of the problem.
The seal between the A/C box and the firewall had perished, allowing condensation to run back into the cabin.
This was the source of the water pooling on the passenger-side front floor.
Repairing the Failed A/C Box Seal
The original Ford seal was too thin, so we used a high-grade sealer around the A/C box spigot and the firewall outlet hole.
This provided a thicker and stronger permanent seal against condensation leaking back into the cabin.
Once the sealing work was completed, we reinstalled the A/C box assembly and the dashboard.
Why Was Water Getting Inside the Ford Ranger?
In this particular 2016 Ford Ranger, the water entering the cabin was caused by condensation from the A/C system leaking back through the failed seal between the A/C box and the firewall.
The diagnostic process was important because the presence of clear water on the passenger-side floor did not immediately identify the source.
We first checked for coolant loss and pressure tested the cooling system. After finding no coolant loss, we continued investigating the A/C system until we identified the failed seal.
This allowed us to repair the actual source of the cabin water leak rather than simply dealing with the wet floor.
If Your Ford Ranger Has Water on the Passenger Floor
Water pooling inside the cabin can be frustrating, particularly when it appears after using the air conditioning.
As this case demonstrates, finding the source may require a detailed diagnostic process.
In this Ranger, the problem involved the A/C box, its condensation outlet and the seal where the A/C box and firewall meet. Accessing the area required removal of the complete dashboard assembly and the A/C box so the components could be inspected properly.
If water continues to appear inside your vehicle, identifying the exact source is important so the correct repair can be carried out.
The Result
After repairing the failed seal around the A/C box spigot and firewall outlet, the problem was fixed.
No more wet floor.
The source of the condensation leak had been identified and repaired, leaving the owner with a dry passenger-side floor and another happy customer.
Need Help Diagnosing a Cabin Water Leak?
If your vehicle is developing water inside the cabin, particularly around the passenger-side floor, the source may not always be obvious.
Contact Abbot’s Auto Care to have the leak properly diagnosed and repaired.