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.