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Automotive Water Pump Repair

April 19, 2021

Automotive Water Pump Repair

Troubleshooting Common Water Pump Installation Errors

The purpose of a car’s water pump is to push coolant through the car’s engine block, radiator and hoses to help pull heat away from the system. Most frequently, the water pump is belt driven off the crankshaft pulley. If a vehicle has a timing belt, it can also be hidden under the timing belt cover on the front of the engine. Its design is meant to last upwards of 100,000 miles but sometimes water pumps fail due to common installation errors. Let’s take a look at the top two mistakes we often hear about.

Top Two Water Pump Problems and Solutions

1. Coolant Flushing and Compatibility

Cause: The cooling system was not properly flushed at the same time the water pump was replaced.
A water pump should never be installed without draining, flushing and refilling the cooling system with the OE specified coolant mix. The seal in the pump is designed only to work with this chemistry. This is the 1 cause of leaks in new water pumps. Coolant has changed dramatically in the last 20 years. All modern vehicles started using OAT (Organic Acid Coolants) in 1996 with GM DexCool (wikipedia). Most all other automakers adopted OAT coolants within the next few years. Asian carmakers use a version called PHOAT (Phosphate Hybrid OAT). Old style silicate coolant still accounts for nearly 60% of all antifreeze sales when the numbers should be 20%.

Solution: Whenever replacing a water pump, ALWAYS drain, flush and refill the system with the OE specified antifreeze/coolant.

2. Water Pump Contamination

Cause: Using the wrong mixture of antifreeze/coolant and water in the radiator.
Vehicles that do not have the appropriate ratio of antifreeze/coolant to water in the radiator will eventually lead to rust on the steel and cast iron impellers. This can result in contamination of the entire cooling system. It can also cause cavitation damage to water pump impellers – leading to multiple product failures.

Solution: Follow OEM guidelines on the antifreeze/coolant to water ratio.
There are different ratios of antifreeze to water used depending on the vehicle and also on the weather. Generally, vehicle makers suggest a 50:50 mix while repair shops in warm climates may use a ratio of 70:30.

Replace All Worn Front End Drive Components

When it comes to water pump replacement, follow OEM guidelines for standard replacement intervals per application or vehicle make and model. The automaker provides the best guideline for replacement if no warning signs are present.

Dayco highly recommends changing all worn front end drive accessory components when a water pump installation is needed. A systems approach is critical to component longevity. A technician should also replace the water pump when performing a timing belt change because the pump is inexpensive and 90% of the labor needed can take place at the same time as belt replacement.

Check out our video on common water pump installation errors to learn more.