Site Information

 Loading... Please wait...

BMW Repair and DIY Blog

Diagnosing a Failing BMW VANOS System - When to Repair Your VANOS

Posted by Jake on

When to Replace or Rebuild your BMW VANOS System

This guide brought to you by BimmerHQ will explain what the VANOS system is, the importance of the technology, and most importantly when and why it should be replaced or rebuilt.

BMW Vanos Replacement Part: Genuine BMW

Click Here to Buy an Aftermarket Branded Vanos Solenoid for $67.99

What the hell is BMW VANOS?

The BMW VANOS (variable nockenwellen steuerung in German) is a variable valve timing technology developed by BMW. The system variably adjusts the timing of the valves by changing the position of the camshaft relative to the drive gear. In simpler terms, it adjusts the camshaft for the intake and exhaust valves, allowing for smoother idling, more torque, and a more elastic powerband.

The first inclusion of Vanos was in the 1992 BMW M50 engine that was used in the 5-Series and only adjusted the position of the intake camshaft. Double Vanos was introduced four years later in 1996 in the S50 engine and featured continuous variability of the intake and exhaust valves, rather than only the intake valve like the single vanos had done.

Here are two diagrams that show how VANOS works, if anyone wants to confuse themselves even more:

How the BMW Vanos System Works

BMW Vanos System

Why do I need to Understand VANOS?

Well, you really don’t. Understanding the Vanos system and the technical and mechanical ideology behind it is a headache and filled with jargon that only advanced mechanics and ECU tuners need to understand. What’s important to us as BMW owners is knowing that the Vanos system is a major electronic component of our engine’s computer system and that a bad or damaged Vanos can cause a decrease in power and torque, rough idling conditions, and poor fuel economy.

Symptoms of a Bad VANOS System

  • Loss of power and torque, primarily in the lower ranges, typically below 3k RPMS
  • Engine hesitation and bogging in the lower rpm ranges
  • Rough idle with frequent hiccups
  • Increased fuel consumption or poor fuel economy
  • Cold start issues and stalling in cold weather
  • Engine fault codes, aka a check engine light

Vanos Fault Codes:

  • P1520: Camshaft position actuator, exhaust
  • P1523: Camshaft position actuator is jammed, exhaust
  • P1397: Camshaft position sensor B
  • 2A82: Vanos intake solenoid (Part #: 11 36 7 585 425)
  • 2A87: Vanos exhaust solenoid (Part #: 11 36 7 585 425)

These are only a few fault codes for the Vanos system, other codes could also indicate a failing Vanos system. If you have a check engine light, we highly recommend buying a code reader and finding out what it is yourself before you pay a shop $100 to plug their scanner into it.

When to Replace a Bad VANOS System

Although there are various symptoms caused by a failing Vanos system, sometimes they are not noticeable at all until the system has just about completely gone bad. Certain engines are good at hiding any symptoms and you may not realize your Vanos has gone bad. Here are a few key mileage points we note:

  • 50,000 Miles: at 50k miles, your Vanos seals are probably just about all worn down. If you do not notice any issues at this point you can go a bit longer without repair, but your car might be performing below par without you knowing.
  • 70,000 Miles: by 70k miles you should repair/replace your VANOS if you have not already. At this point, your seals will be worn out and your car will have less power in the lower ranges, whether or not you notice it.

When you replace your Vanos you will notice an increase in lower range power, up to about 3k RPM’s, you will improve your fuel efficiency by a decent amount, and it may solve any rough idling that your car has (this can also be caused by spark plugs or the spark plug gapping). A lot of the time you won’t notice that your car is underperforming, especially if you haven’t experienced it at full performance, and therefore will be hesitant to repair a part that isn’t technically broken yet. But we recommend replacing the seals and the whole system around 70k miles if not earlier. We consider it preventative maintenance and you will notice a difference in the performance and smoothness of your ride.

Click here to read our E90 Vanos Solenoid Replacement DIY

Click here to request a DIY guide, blog post, or anything BMW related

BMW E46 Engine Tuning Guide

BMW E46 Engine Tuning Guide for Beginners We get the question all the time “How can I get more horsepower out of my E46?”, “What mods can I do to make my E46 faster?” and so on. This guide brought to you by BimmerHQ is meant to serve as a guide for new E46 owners looking to tune their [...]

Read More »

BMW E46 Control Arm and Bushing Replacement

BMW suspensions provide some of the best driving in the world. Their cars feature high ratios of sprung to unsprung weight. Unfortunately, this can lead to higher vibration levels due to worn BMW E46 parts, including E46 control arm bushings, ball joints and wheel bearings. These instructions show how to replace weak front-end control arm [...]

Read More »

How to change your BMW Oil DIY

No DIY maintenance is easier – or more important – than changing your oil at specific intervals. Failure to change you oil when required can lead to a sludgy buildup, especially in the fuel injectors. This will cause your beloved BMW to lose power and may even damage your engine. We recommend you splurge and [...]

Read More »

Blower Resistor FInal Stage Unit Replacement BMW E39 E46

The BMW E39 and E46 Series are great cars and very popular. However, they seem to suffer from a chronic problem with the final stage unit E46. Symptoms are a haunted blower that seems to have a mind of its own. It can cut out without warning or get stuck on a single setting. The [...]

Read More »

BMW E46 Thermostat Replacement

The typical way this thermostat fails is to be stuck in the open position. There are a few tip-offs: longer warm-up times, unusually temperature gauge readings, and even an engine light. Here's how to replace a bum thermostat:Preparation Confirm the error code corresponds to a faulty thermostat. Gather your tools: 10, 11 and 13 mm [...]

Read More »

BMW Water Pump Replacement E46 E39

Water pumps fail from time to time. Also, sometimes car owners replace their water pump whenever the thermostat fails. Follow these instructions to replace the water pump on your BMW 3-Series (1992-2005) and 5-Series (1997-2005).Tools Needed Sockets: 10mm, 8mm Allen T-25, T-50 bits (2) M6 bolts to extract water pump Pliers Screw driver Drip pan MarkerSteps Drain coolant into drip pan. Remove the underbody [...]

Read More »

Vent Valve Replacement for BMW 540i, 740i, 740il

You may be alerted to the need to replace the rear intake manifold vent valve on your 1996-2003 model by an engine squeal or chatter. If you pull out the dipstick, you'll hear air rushing in and may notice a change to the idle. An engine code of P1159 or P1161, which point to the [...]

Read More »

Cooling System Bleed BMW E38 E39

Air in the coolant system may lead to engine overheating. Removing the radiator cap from a hot system will simply allow more air to displace escaping boiled-over coolant. Here are the instructions for bleeding air out of the engines found in these models.1) Preparation Make sure the engine is cold. Add coolant until the [...]

Read More »

Installing Valve Cover Gasket BMW E46

This is considered a moderately easy installation. You should budget about two to three hours of deliberate, careful work. This particular install was performed on a M54 engine in a 2001 325Ci, but same gasket fits model years 1999 – 2001.Tools: Spark plug socket Flat head screwdriver Socket wrench 8, 10mm socket T30 Torx bit and driver DegreaserSteps Remove the cabin filter [...]

Read More »