BMW is a luxury car brand synonymous with reliability and performance. With gorgeous designs that are packed with the latest innovations and a comfortable interior to match, it’s definitely easy to see why so many people are die hard fans. However, no brand is ever perfect, and every make and model will have its own foibles or propensities for certain part failure that their owners need to watch. In the case of BMW, a common part failure across several models involves the water pump. In this article, we will take a look at some of the signs and symptoms of failure as well as discuss the best way to deal with this type of problem.
What does the water pump do?
A functioning water pump is essential to the cooling of your engine. When driving, your engine produces a lot of heat, enough to cause parts failure and even warp metal. To prevent this from happening, your BMW has a cooling system in which the water pump is responsible for pumping coolant around this system. This keeps your engine at a safe temperature. The pump is responsible for regulating the flow of coolant to maintain a safe running temperature. It is powered externally, typically by a pulley and belt combination.
The Visual Signs of a Failing Water Pump
If you’re a little DIY-handy and you suspect your BMW’s water pump is failing, you can pop the hood and take a look at the condition of the pump. A simple visual inspection can tell you a great deal about the status of your water pump as well as what could be causing it to fail. This can also indicate the steps you may wish to take to remedy the issue as the table below shows.
| Problem |
Visual Appearance |
Likely Cause of Failure |
What to do |
| Weep Hole Leakage |
When a new pump is installed, some leakage or weeping is expected. However, in general, there should be a tight mechanical seal of the shaft. Even so, a large coolant bleed mark or drips from the weephole after the pump has been broken in is abnormal. This is indicative of impending pump failure. |
Contaminated coolant |
Flush the coolant system and replace the pump. Add new coolant.
Seek professional maintenance or servicing if you are inexperienced in this task. |
| Mounting Surface Leak |
The mounting surface or housing has signs of drips, seepage or coolant bleed marks. |
Incorrect installation of the water pump, or the incorrect use of seals or gaskets. |
If recently installed, the pump can be removed and reinstalled correctly. If not, seek a replacement installed by a skilled professional. |
| Corrosion or Rust |
Rust or corrosion anywhere on the surface or surrounding areas of the water pump. |
Contamination of coolant, incorrect coolant, mixing or coolant or a defective pressure cap. |
Replace the water pump and flush the coolant system. Inspect the pressure cap and replace if needed. Refill with correct coolant.
Seek professional maintenance or servicing as required. |
| Build-up of Deposits |
Sludge, deposits, and build up of scale that is clogging or obscuring the pump. |
Contaminated coolant, mixing coolants, or incorrect coolant. |
Flush coolant, replace pump, refill system with correct coolant. Be sure to seek professional help in this task if inexperienced. |
| Cavitation |
Pockmarks and wear to the pump, possibly resulting in spots or corrosion. |
Formation of bubbles at the pump’s coolant inlet. When under pressure these bubbles explode with great force, creating the pockmarks. |
Flush and replace the coolant, then replace the pump. Be sure to have this work done at a recommended auto repair shop. |
Seek Repairs
As with any type of fault or part failure, it is 
great to be able to diagnose the issue. However, if you’re in any doubt of your skill or the steps you need to take to repair or replace the broken part, you should definitely allow the professionals to take the weight off your shoulders.
Luckily, if you are a resident of Englewood, Littleton, Centennial, or Denver, CO and are worried about making repairs yourself, then the friendly team at DART Auto are ready to offer you a helping hand. With a 3 year/36,000 mile warranty on all labor and consistent 5-star reviews, you can rest easy knowing that we will get you back on the road safely.
