8 Common Audi 4.2L V8 FSI Engine Problems (& Solutions)

Are you in the market for a used Audi with the 4.2L engine? Well, if that is the case, you are in the right place. In this article, we are going to elaborate on everything when it comes to this engine.

Doing your own research before you decide to buy a car with a specific engine is the thing you need to do, always. There are a lot of Audi models with different engines, and some of these engines have pretty poor reliability. And you definitely don’t want to take a chance on something expensive like an Audi. This is why we are here to help you out.

First, we are going to learn the basic Audi 4.2L engine specs and then we will cover the common Audi 4.2L V8 FSI engine problems as well as the applications of this engine. Lastly, we will answer some frequently asked questions. So, without further ado, let’s dive in.

Basic Audi 4.2L V8 FSI Engine Specs

Now let’s first cover the engine specs for the 4.2L FSI. The 4.2L FSI engine is a 90-degree V8 engine that was produced by Audi and is used in brands from the Volkswagen Group like Volkswagen and Audi.

This 4.2L FSI engine is a heavily revised version of the older 4.2L engine that Audi produced. This engine includes all new internal components. There are different rods and pistons, a new crankshaft, improved cylinder heads, an improved oiling system, as well as an improved engine management system.

This engine comes in two variations, a comfort one, used in luxury vehicles, as well as a sport version that is used on sports models like the Audi R8.

The FSI abbreviation stands for Fuel Stratified Injection. This system was developed by Audi for their Le Mans R8 race car.

The outputs that this engine produces are very different based on the application where you can find this engine as well as the version, whether it is a 32-valve or 40-valve model. 40-valve engines in the FSI family produce less power compared to the 32-valve ones.

The most common applications for the 32-valve engine are the Audi A6, A8, and Q7 for the comfort version. And the R8, RS 4, and RS 5 for the high-performance model.

Detuned Comfort Version

This 32-valve version of the engine produces 257 kW (345 bph) @ 6,800 rpm and 440 N-m (325 lb-ft) @ 3,500 rpm.

Sport Version

The sport 32-valve version of the engine is rated at 331 kW (444 bhp) and 430 N-m (317 lb-ft) @ 4,000 rpm.

Common Audi 4.2lL V8 FSI Engine Problems

Now let’s list the common problems that this engine has.

  • Intake Manifold Failures
  • Spark Plug & Coil Failures
  • Timing Chain Guide Failures
  • Variable Valve Timing Solenoid Failures
  • Injector Failures
  • High-Pressure Fuel Pump Failures
  • Carbon Buildup
  • Oil Leaks

We briefly listed the common problems with this engine, now let’s further elaborate on them and learn how serious these problems are in the first place.

Intake Manifold Failures

The first problem on our list is the intake manifold failure. These engines use a very complex intake manifold that is known to malfunction on a lot of these Audi models.

These failures occur somewhere in the range of 200,000 and 250,000 kilometers. What happens is that the inside of the intake manifold will get extremely dirty and will prevent the flaps from opening and closing correctly.

This intake manifold also has two electric actuators that actuate these flaps that are located inside and these actuators can also fail.

The intake manifold is a bit overcomplicated and this complexity makes it very expensive to fix or replace if replacement is needed. In some cases, it can cost more than the actual engine to replace this intake manifold on these cars.

Spark Plug & Coil Failures

The next problem on our list is the spark plug and coil failures. Spark plugs and coils are notorious for failing on many Audi or Volkswagen engines and the 4.2L is no exception to this rule.

If you own this engine, you will expect to replace spark plugs and coils more frequently compared to other engines.

This is the case because the ignition coils do not last for a very long time. So, you have to be prepared for this type of problem if you opt for this engine.

When it comes to symptoms, there will be the check engine light, engine misfires, rough idle, and overall poor engine work.

Timing Chain Guides Failures

Timing chain guides are also quite notorious for failing on these engines. The timing chain guide as its name implies is the component that keeps the tension on the timing chain and guides the chain.

These guides on the 4.2L engine are made out of plastic. And what can happen is that they can start to wear at higher miles and allow slack to develop on the timing chain. They can also break into two pieces.

This allows the timing chain to start creating rattling noises. These noises can be very annoying to deal with and on top of that, they can also total out the engine. Especially if the timing chain skips timing.

This is why when there is a rattle from the engine, it is recommended to replace the timing chain guides and the tensioners.

Variable Valve Timing Solenoid Failures

This engine uses a technology known as variable valve timing. This gives the ability to the engine to either advance or retard the position of the camshafts in order to maximize the power delivery and fuel economy.

This variable valve timing system is regulated by solenoids. In total, there are four of these solenoids, one per each camshaft.

When they engage, the VVT system activates. And when they don’t engage, you will get the check engine light. There are other symptoms like loss of power and limp mode in some cases. Replacing them is a straightforward job.

Injector Failures

Injector failures are also common on some higher mileage engines. This engine uses direct injection. So, these injectors are high-pressure fuel injectors.

They tend to fail often and end clogged up. The solution to this problem is to either clean them with a special injector cleaning fluids. Or, if you want to play it safe, just replace them with new units.

They are not very expensive, like diesel injectors are. Replacing them will guarantee that you will not suffer any more running issues in the future.

High-Pressure Fuel Pump Failures

This engine uses direct injection, this system requires that the engine implements a high-pressure fuel pump. The fuel has to be injected at a certain pressure in order for this system to work.

So, these high-pressure fuel pumps are doing all the hard work. These components are located on top of the engine and are injecting the fuel.

What can happen is that they can fail or start to leak fuel and cause running issues. The car will not be able to start or the engine can stutter if the pump is not good. Luckily, replacing these components is not very laborious because they sit on top of the engine.

Carbon Buildup

Another common problem with this 4.2L engine is the carbon buildup that develops. This engine is using direct injection as we noted.

This means that fuel is not injected through the intake ports as in other older designs. This means that the engine intake valves will not be properly cleaned.

There will be carbon deposits on the valve stems and if the carbon buildup becomes too excessive, it will prevent them from working properly.

This is why something called walnut blasting was invented. With this process, you can clean the carbon deposits and make sure that the engine works well. This process should be done every 60,000 miles (ca. 96,561 km) in order to avoid problems with the engine.

Oil Leaks

This engine is also notorious for developing oil leaks. Oil can leak from various places on the engine. Namely, the timing covers, valve cover gaskets, oil cooler, oil filter housing, and around the oil cooler.

What is bad about this engine is that it is very compact. And fixing some of these problems can require complete engine removal. This can be very expensive to do and this is why before you buy a car with this engine, make sure that it doesn’t have any leaks.

What Models Have The Audi 4.2L FSI Engine?

This engine was included in a variety of VW Group products. This list includes both the 32v and 40v engines.

Regular Low Power 4.2L Engine

  • VW Touareg 2006 – 2010
  • VW Phaeton 2003 – 2010
  • Audi A6 2006 – 2010
  • Audi A8 2006 – 2010
  • Audi Q7 2006 – 2010

High-Performance 4.2L Engine

  • Audi S4 2002 – 2005
  • Audi RS 4 2005 – 2008
  • Audi RS 5 2010 – 2017
  • Audi R8 2010 – 2015


What Are The Common Audi 4.2L V8 FSI Engine Problems?

This engine has a lot of problems. These problems include carbon buildup, injector failure, and high-pressure fuel pump failures. There are also problems with VVT solenoids, problems with spark plugs, and ignition coils. Also, oil leaks are frequent. And the most serious problem is probably the timing chain guide and tensioner failure that can occur.

Is The Audi 4.2L FSI Engine Reliable?

This engine is mechanically good. But the mechanical components are not always the ones that make the reliability of an engine. There are a lot of accessories that can fail on this engine and can cost a lot of money to be replaced. Sorting these problems can cost thousands of dollars since service procedures on this engine are very complex. This is why we give this engine a below-average reliability score.

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