Inside The BMW Electric Water Pump: A Tech Tip
A more recent Maine BMW 535 wagon just had an electronic water pump replaced; it’s a fascinating piece of technology! The water pump in most cars, including earlier BMWs, is driven by a belt on the front of the engine. This is a tried-and-true design, but it does not allow for dynamic control. BMW has added an intriguing twist as it switched from the older “M” engine to the new “N” designs: an electronic engine coolant/water pump.
A truly clever invention, an electric water pump allows for greater control over engine running conditions. To hasten the engine’s warm-up process and accurately regulate engine temperature, the electric pump can be turned on and off as necessary. Additionally, the parasitic drag of a belt-driven water pump is removed, theoretically enhancing engine efficiency and performance. Anything mechanical is susceptible to failure, and in the case of this vehicle’s electric pump, the electric motor that rotates the pump impeller and circulates the engine coolant failed.
We reasoned that a picture documentary might be appropriate in this situation given that this is a fairly novel design and few people have seen the interior workings of the pump. As you can see, the pump impeller is marked “VDO,” which has been a longtime supplier to the majority of German businesses. Additionally, what looks to be a NiCad battery inside the pump’s electronics may actually be a huge capacitor. This truly attracted our attention, and we’re investigating what the goal is in detail. The capacity would appear to be insufficient to power the pump, but we are confident that the BMW experts have a justification.
In This Article...
BMW Electric Water Pump Failure: Causes, Effects, and Prevention
This BMW 540 has a faulty engine coolant pump, according to the diagnosis. Overheating and a broken drive belt system were the symptoms. The front cover had to be taken apart, and the water pump had to be taken out to be examined.
This pump’s failure mode seems to be basic aging and mileage, probably made worse by a dearth of coolant changes. The pump’s bearing broke, allowing the plastic impeller to come into contact with the metal casing, and you can see the resulting surface growth. The car eventually overheated, the plastic impeller failed, and it stopped. Since the water pump impeller is composed of plastic, it can become brittle with time and extended exposure to the hot engine coolant. In certain cases, this can cause the plastic to simply shatter apart without a bearing failing. On the left side of the picture are the damaged pump and bits of the broken impeller, and on the right is the replacement pump.
We advise replacing these water pumps at every 80,000 miles. Usually, failure happens fairly shortly after the car reaches this mileage milestone. There is a better pump out there; we use one with a metal impeller as opposed to a plastic one. The engine thermostat should always be replaced at the same time as any cooling system component that needs to be replaced because the thermostats have almost definitely been harmed by the overheating and doing so is a cheap form of insurance. It takes some work to get to the pump, as you can see from the photographs, therefore always swap out the drive belt and tensioner at the same time.
In addition to preventing freezing, antifreeze also has corrosion inhibitors and lubricants for the water pump bearing, but they both lose their effectiveness with time and need to be replaced with a coolant flush. As the engine in this vehicle is made of aluminum alloy, it is always a good idea to flush the cooling system at least every three years and to use corrosion-inhibiting antifreeze.
How do water pumps function?
Impeller blades in a water pump typically rotate off of an accessory belt that runs off the crankshaft pulley. In order to optimize efficiency and free up engine power in modern BMWs, water pumps are now electrically driven. The impellers of the water pumps turn, cycling the coolant through the system. Conduction removes heat from the engine block when the coolant runs through it; the heat is then transferred to the radiator. The coolant goes through the radiator as air passes over it, cooling the temperature of the coolant in the process. The cycle is then repeated.
How to Perform a Self-Bleeding BMW Electric Water Pump
An electric water pump has recently emerged as the preferred option for contemporary cooling systems. BMW’s engineers were able to save expenses and simplify engine maintenance by switching from a belt-driven pump to an electric one. The owner will earn more money and spend more time traveling if they spend less time in the shop.
Additionally, the electric pump added a self-bleeding process to the vehicle, making the laborious process of bleeding the system into something you’ll never have to consider. It was at best challenging to bleed the cooling system on earlier models of BMW. The engines frequently developed air pockets that interfered with cooling. However, any problems you could have bleeding the system are eliminated by the self-bleeding procedure included to the F30 chassis.
The purpose of BMW’s electric water pump
Failure of the water pump is one of the issues that BMW owners experience most frequently. This is because BMW uses an electric water pump instead of a conventional mechanical water pump in their vehicles.
By moving water around a sort of “water jacket” encircling the engine, water pumps assist in preventing overheating. Without it, your engine’s metal components may expand as a result of unregulated heat, causing some of the parts to grind or even weld together.
Your timing belt powers conventional mechanical water pumps, allowing them to circulate coolant throughout the system. Because of this, mechanical water pumps frequently come at the expense of some horsepower and fuel economy.
In fact, electric water pumps, like those used by BMW, outperform their conventional counterparts. Electric water pumps assist you maintain the horsepower and fuel efficiency of your car by drawing power from the battery. Electric water pumps are often seen in racing vehicles, however BMW includes them in all of their vehicles as part of their commitment to luxury.
When did BMW begin use electric water pumps?
Street-driven vehicles can use electric pumps; in fact, BMW started utilizing them around 2007 and a number of other manufacturers are developing equivalent models.
What’s the process of an electric water pump?
However, how does a water pump assist? Pumping coolant into the engine and absorbing engine heat is how it operates. After entering the radiator to cool off, the heated coolant returns to the engine in a closed loop.
To transfer coolant from the cooling system to the engine components, an electric water pump uses a motor. When the powertrain begins to overheat, the system activates. When the signal reaches the ECU, it starts the water pump. The torque of the engine is used by conventional pumps, also known as mechanical water pumps, to power a belt and pulley system. The coolant is poured more quickly the harder the engine is working. The fluid makes its way from the radiator to the cylinder heads, then the engine block, and ultimately back to the radiator.
The cooling fan and HVAC system are both connected to the water pump. When the heater is on inside the car, the HVAC system employs the fan to help cool the hot liquid.
The BMW auxiliary water pump: what is it?
Auxiliary water pumps are standard on all large BMW models with mechanical main water pumps, and they serve two purposes: they enhance coolant flow around the cabin heater when the engine is idle and they maintain coolant flow after the engine is turned off so that the cabin may be heated.
How durable are BMW electric water pumps?
Water pumps are intended to endure for at least 100,000 miles, but if yours breaks down, you should replace it with a premium piece of original equipment. There are less expensive replacement pumps available, but they may only last 30,000 miles.
How can I tell if the electric water pump in my BMW is damaged?
Another significant factor in the equation is age and distance. Despite any other issues, you might want to think about installing a new water pump if your automobile has logged tens of thousands of kilometers. Water pumps do not last indefinitely, so if yours has served you well for 75,000 miles with no issues at all, it may be time to think about replacing it so you don’t end up on the side of the road when your water pump decides it has outlived its usefulness.
How is an electric water pump started?
It’s likely that your water pump has lost pressure if you’ve left it off throughout the winter. Your water pump will require priming in order to start functioning once more. To get the pressure the pump needs to start pumping again, water must be pumped back into the pump and flushed through. We’ve put up a brief guide to walk you through the fundamental procedures of priming your water pump.
1. Verify that the power is off.
When working on a pump, never leave the power on. Check the breaker panel to make sure that the electricity is switched off; you might even want to peek at the pump’s base to make sure.
2. Get inside the pumping system
The next step is to locate a plumbing fixture that will enable you to gain access to the pump system. On a pool pump, this will be the strainer basket, which is typically the fixture closest to the water tank.
3. Examine any damage.
Make careful to give the pump a thorough inspection. Pay close attention to fittings like pipework for deterioration like cracks. It is much more crucial to perform these tests extensively if the system was shut down for the winter. It will be necessary to inspect drain plugs for problems like retightening. Manually operating the valves to ensure proper operation is an useful technique to inspect them. Examine the belts, pulleys, and safety guards after making sure that all of the hardware, such as nuts and bolts, is securely fastened.
4. Examine a hose
Once you’ve located a hose, make sure you have clean water by briefly washing the hose through. Never drink from a garden hose that might contain lead; take care. However, if you’re utilizing a well pump and thoroughly filter the water before and after it passes through the hose, the water should be fit for human consumption.
5. Deactivate the relief valves.
Keep an eye on the pressure gauge as well. This is to prevent pressure from building up.
6. Screw the hose on.
On a typical water pump, connect the fixture to the closest water tank. Use the strainer basket to contain the hose if you’re using a pool pump.
7. Start the water and let it fill the tank before turning it off.
As the tank fills, you ought to hear the water running or see the water pressure gauge rising. Before you close the lid on a pool pump, the strainer basket needs to be full. When you notice water gushing out of the other end of the hose, turn off the water supply.
8. Switch on the power
Allow the pump to run for about a minute. If you had any relief valves open, let the water start to flow through them before closing them once more. Pump is primed if it shuts off naturally. If not, you might have to go through it again.
Look no farther than our selection of various water pumps if you’re still looking for a dependable water pump. We now have a selection of self-priming pumps available for people who struggle with the priming procedure.