BMW is an iconic manufacturer with a long history of luxury cars. They are known for their brilliance in the field of engineering. With some of the most classic and stunning designs on the market, and some of the smoothest driving around, BMWs are a firm favourite nationwide.

When it comes to the aforementioned incredible driving, one part becomes essential: the VANOS system. This system is responsible for making the drive feel powerful and yet smooth. However, when this part isn’t functioning, you’ll notice a dramatic decline in the performance of your BMW.

With this in mind, in this article, we will take a closer look at the VANOS system as well as highlighting some of the warning signs of failure.

What is the VANOS system?

VANOS is an abbreviation of the German words “VAriable NOckenwellen Steuerung.” It is BMW’s iteration of the engine variable valve timing unit. First released in 1992, this modification to the engine system allows for vastly improved engine performance due to the reflexive opening and closing of the engine intake and exhaust valve. This process increases torque and improves the smoothness of idling. The VANOS system is able to control the oil flow to the cam gears too, through the use of solenoids. This allows for very precise timing adjustments.

Types of VANOS System

There are 3 types of VANOS system that your BMW may have, and each has its own issues that are more likely to occur with time and use so being aware of these can help you to correctly identify warning signs:

Single VANOS

1992-2000 in 6-cylinder M50, M52, & S52 engines
1999-2002 in V8 M62TU engines

Double VANOS

1999-2005 in 6-cylinder M52 TU, M54, & S54 engines
2004-2010 in 6-cylinder N54

Double VANOS with Valvetronic

2004-2010 in 6-cylinder N52 & N55
2004-2010 in V8 N62 & N62 TU engines
2005-2015 in V12 N73 & N74 engines

Common Trouble Signs of a Bad VANOS System

In general, issues with the VANOS system are directly connected to the decline in engine performance as well as efficiency and economy, since the VANOS system is responsible for looking after this. Therefore, if the VANOS system begins to fail, you are likely to notice one or more of the following issues:

1. Loss of Power/Torque

Because the VANOS system is solely responsible for maximising the amount of power and torque produced by the engine, if the system fails, the power and torque will become reduced.

2. A Hesitating Engine at Low RPM

Your BMW will begin to struggle at low RPMs, as the VANOS system is responsible for maintaining the correct crankshaft speed. Therefore, without it working correctly, your engine will struggle to maintain power at lower RPM.

3. Rough Idling

As your VANOS system is designed to smooth out idling, without it working correctly, you’ll notice that idling becomes much more rough.

4. Increase in Fuel Consumption/Reduction in Fuel Economy

The VANOS system keeps your engine working at its optimum level. However, without it working, your engine will not be able to achieve maximum efficiency, resulting in fuel consumption increase and economy decrease.

5. Cold Start Issues

Starting your car in cold weather can be tricky even with a working VANOS system, but if the system fails, you’re likely to notice this becomes much more difficult.

6. Stalling in Cold Weather

On a similar theme to the above point, without the VANOS system keeping the engine working at an optimal level, you’re likely to notice an increase in stalling when the weather gets cold.

7. Fault Codes

Because your VANOS system is connected to the engine, the OBD (on-board computer) will monitor it closely. Therefore, if it begins to fail and impact upon the engine’s performance, you’re likely to notice the OBD will release various error codes, such as the check engine light.

8. Engine Feeling Limp After Accelerating

Acceleration can put strain out on your engine. The VANOS system will regulate this so that acceleration and deceleration become smooth with a steady increase and decrease of power. However without the VANOS system working properly, the engine can drop dramatically in power after acceleration instead of steadily, resulting in the engine feeling limp.

Master Mechanics Auto Repair

If you live in or around Battle Creek, Portage, or Kalamazoo, MI, and are looking for experts in VANOS system repairs, then look no further than Master Mechanics Auto Repair. At Master Mechanics, prices are affordable, our staff is friendly, and our technicians are knowledgeable, ensuring you always drive away happy with less cost than dealerships.

* BMW Car image credit goes to: DarthArt.