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Audi A4 Water Pump

Troubleshooting Problems with the Audi A4 Water Pump

The water pump is one of those components of the Audi A4 that people often overlook until it needs replacing. Though it is not included in Audi's list of parts that undergo regular service and replacement, experts recommend replacing the water pump every time the timing belt is serviced (which is usually 60,000 to 90,000 depending on the quality of the belt). Some pumps may not last that long, however, and may show signs of wear and malfunction long before the timing belt it's connected to has reached its service. In this article, we're going to teach you the tell-tale signs on common problems with the Audi A4 water pump and how to troubleshoot them.

Dirty seal leakage

There have been cases of Audi A4 pumps that leak rusty-looking coolant with mud-like consistency leaking out of the weep hole which, when dried, leaves residue of rust and calcium on the pump's exterior surface. This is typically due to the use of water with high mineral content (such as tap water) as coolant which creates rust inside the pump and, when heated, builds up deposits that restrict the flow of coolant and creates the leak. Flushing the cooling system and using distilled water or a synthetic coolant usually solves this problem, but if it still persists the pump may already be severely deteriorated and must be replaced.

Broken pump shaft

Water pump shafts tend to break dramatically, usually sending the clutch fan straight into the radiator body and damaging the pulleys, fan shroud and other cooling system components. This is due to the failure of the water pump bearings from the sudden overload caused by imbalance or vibration. If the break is a clean fracture, the shaft may have fractured suddenly by rapid engine acceleration, but if there is a blue heat discoloration the water pump has experienced excessive heat buildup prior to breaking apar. Replace the pump and other components damaged by the broken pump shaft and check the pulleys for misalignment of fatigue and repair them accordingly.

Broken pump cast

There have also been some instances of the water pump cast fracturing and breaking apart, usually around the bearing support. This is usually due to excessive vibration from a badly worn fan clutch or bent fan blades. Replace the broken pump, the fan clutch, and fan if necessary.

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  • Tips on Maintaining the Audi A4 Water Pump

    An Audi A4 water pump can last as long as 10 years of continuous use before needing replacement, but in order to achieve this it must be maintained on a regular basis. Though it is not usually one of the things that people do maintenance on, the water pump can provide years of decent - if not exceptional - performance if maintained properly. And maintaining the pump is quite easy and just requires spending a bit of effort and removing some old habits. So if you want to get the most value out of the water pump in your A4, just follow these simple maintenance tips.

    Skip the tap water.

    A lot of people often make the mistake of using water from their tap as coolant as a cost-saving measure. But while tap water is more affordable than distilled water or synthetic coolant, it can actually do more harm than good for the water pump. This is because untreated water contains minerals that can build up inside the water pump, restricting flow and causing the pump to leak in the seals. In addition, tap water is more likely to cause rust inside of the water pump, contaminating the entire A4 cooling system and requiring a costly flushing in order to clean up. So unless it's for emergencies, switch to distilled or synthetic coolant instead.

    Check for leaks regularly.

    Leaks are the most frequent problems in water pumps, and through frequent inspection the risk of leaks and overheating is drastically minimized. A simple yet effective way to check for leaks is by placing a piece of white cardboard underneath the vehicle overnight. If there is a leak in the water pump, the cardboard should be soggy the next day. In addition, check the pump, seals and hoses for visible signs of cracks where coolant can leak out of.

    Don't add coolant while the engine is hot.

    Pouring cold coolant into the tank while the engine is smoking hot can lead to thermal shock, causing cracks on the pump's seal face the mating ring. Let the engine cool before adding the coolant, turn on the engine and let it run while slowly adding what's left of the substance.