Owner's Problem Description
The owner is attempting to remove the heater supply and return tubing for the rear heater on a 1999 Chrysler Town & Country with a 3.8L engine. The tubing is loose and runs along the backside of the firewall, extending down under the passenger floorboard. However, there isn't enough space to completely work the tubing out, leading to frustration in the repair process.
Professional Technical Analysis
The 1999 Chrysler Town & Country with a 3.8L engine typically experiences issues with the rear heater hose removal due to limited working space under the dashboard. The heater supply and return lines often become difficult to access, especially when trying to disconnect the quick-connect fittings located near the firewall. These fittings can be problematic, as they are prone to shrinkage and leaks in cold weather, which could lead to coolant loss and heating issues. The quick-disconnect fittings have been known to fail, prompting a Technical Service Bulletin (TSB) that suggests replacing them with an improved design featuring two O-rings. However, a more practical long-term solution is to bypass these fittings entirely and run bulk heater hose from the supply to return. This approach simplifies the maintenance process and reduces the chances of future leaks. To facilitate the removal of air pockets from the rear heater core, the system should be pressurized by either warming the engine or using a cooling system pressure tester, while monitoring the hoses to ensure proper coolant flow and air escape. Given that these hoses can be challenging to maneuver, it's advisable to consider alternative methods such as using the old hoses to secure the new bulk hoses in place. Overall, careful consideration of the workspace and the choice of materials can significantly ease the repair process.
Possible Causes
Most common causes (ordered by frequency):
- Quick-disconnect fittings failure: The quick-disconnect fittings on the heater hoses may shrink and leak, especially in cold weather. The original design is prone to failure, leading to coolant leaks and air pockets in the heating system. Replacement with updated fittings or bypassing them with bulk hose is recommended. - Frequent coolant leaks, heater performance issues, TSB references for quick-disconnect fitting failures.
- Insufficient space for hose removal: The design of the vehicle limits access to the rear heater hoses, making it difficult to remove them without significant disassembly of the dashboard or passenger compartment. - Visible obstruction when attempting to access hoses, required vehicle disassembly steps noted.
- Air pocket in heater core: If air pockets develop in the rear heater core, it can lead to inadequate heating and coolant flow issues. Proper bleeding procedures must be followed to ensure efficient operation of the rear heating system. - Poor heating performance, presence of air pockets during coolant testing.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Visual Inspection: Begin with a thorough visual inspection of the heater hoses and quick-disconnect fittings. Look for signs of leaks, wear, or damage. Ensure that the hoses are properly secured and that there are no visible hazards obstructing removal.
- STEP 2 - Disconnecting Quick-Disconnect Fittings: Carefully disconnect the quick-disconnect fittings using appropriate tools. If necessary, use lubricants to ease the removal process. Be prepared for potential coolant spillage and have a catch pan ready.
- STEP 3 - Hose Removal: With the fittings disconnected, attempt to maneuver the heater hoses out of the confined space. If difficulties arise, consider removing any necessary components that may obstruct the hoses, such as the dashboard or surrounding panels.
- STEP 4 - Air Bleeding Procedure: Once the hoses are removed, follow the proper air bleeding procedure for the rear heater core. This may involve running the engine with the heater on and monitoring the coolant level, or using a pressure tester to force coolant through the system.
