Tech Tip: Coolant Leak Leads to Unnecessary Pump Replacement – UnderhoodService

Tech Tip: Coolant Leak Leads to Unnecessary Pump Replacement

A coolant leak from a source above the water pump or from an improperly installed bypass tube on the water pump itself will cause coolant to pool on top of the timing cover on 1993-2003 Dodge trucks and Jeeps. This coolant then rolls across the front of the pump and behind the pulley, making the pump appear to leak from the weep hole. This often results in unnecessary pump replacement ....

Affected Vehicles:
1993-2003 Dodge trucks and Jeeps, 3.9L V6, 5.2L & 5.9L V8.

Condition:
A coolant leak from a source above the water pump or from an improperly installed bypass tube on the water pump itself will cause coolant to pool on top of the timing cover. This coolant then rolls across the front of the pump and behind the pulley, making the pump appear to leak from the weep hole (Figure 1). This often results in unnecessary pump replacement.

Cause:
The pulley on this pump completely covers the face of the pump, making the correct diagnosis difficult (Figure 2). The bypass tube that is shipped loose in the box is often installed without sealant or is not tightened properly. The subsequent leak can cause antifreeze to gather on top of the timing cover, which is difficult to see. There are other components above the water pump, including the thermostat housing and the bypass hose, that can leak and cause antifreeze to gather in the same place and eventually mimic a leaking water pump.

Correction:
When replacing this pump, the supplied bypass tube should be installed with thread sealant and should be properly tightened before installation of the pump. The bypass hose and clamp should be inspected for wear, holes or other flaws before they are reused and the area should be inspected for evidence of other leaks, such as from the thermostat housing. The original leak that prompted the pump to be changed may still be present and will need to be addressed.

Tech Tip courtesy of ASC Industries, Inc.

For information of products offered by ASC Industries, visit www.asc-ind.com.

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