Audi B8 S4 Engine Problems: Reliability, Specs & Reviews

With its release in 2008, the B8 S4 became quite popular, mainly due to the use of an amazing V6 engine that is still competent as of 2021.

With HP and torque easily crossing the 300 marks, it is a solid performer.

This article will be focused on some of the Audi B8 S4 engine problems, which users commonly reported.

They are:

1. Unexpected Misfires
2. Failure Of The Water Pump
3. The Build-Up Of Carbon In The Engine
4. Transmission Failure

All of the above issues are to be deemed level critical. This article will be focused on describing the cause of the issues and what can be done to diagnose and fix them.

So, without any further ado, let’s get straight into it!

The 4 Most Common Audi B8 S4 Problems

This section of the article will now be focused on the issues outlined above.

It is recommended to read this part of the article in its entirety, so you will not miss anything.

1. Unexpected Misfires

Unexpected misfires are more of a symptom rather than an issue.

It can be caused due to several factors, which will be discussed below. Misfires can affect your daily driving and can result in fatal accidents.

The Cause

Misfires can be triggered due to many reasons.

The most common ones on the V6 engine are:

• Faulty fuel injectors.
• Failure of the ignition coils.
• Worn out spark plugs.

Fuel injectors are responsible for spraying fuel into the cylinders while the ignition coils and spark plugs work in tandem to help combust the fuel, which is needed for powering the engine.

Any one of them can cause the issue of unexpected misfires.

Repair

The B8 S4 engine uses coil packs instead of individual ignition coils. The technology is the same, with the difference that the whole coil pack needs to be replaced.

It is already advised to get all of the coils replaced except for one, so there is no chance of a mistake.

The same goes for the spark plugs. They need to be replaced after a few thousand miles. As for the injectors, they are most probably clogged, and cleaning them should do the trick.

It is advised to get all of this work done by a professional.

Although the replacement process of the coils and the plugs can be done yourself, you need to be sure that they are the ones causing the issue.

Avoiding Future Problems

So, what can one do to avoid the issue of misfires again?

It is incredibly inconvenient, and you must get them replaced at every 50000-mile interval. This way, you can be sure that you will not have to face the issue again.

2. Failure Of The Water Pump

Function

The water pump is something that can go bad on any vehicle. Let me explain to you the function of this part.

Although it has been named a water pump, it is responsible for pumping coolant throughout the engine.

The proper functioning of the pump is crucial to keeping the temperature of the engine down.

So, how can the water pump become faulty?

Well, there is only one possible reason for it: the failure of the impellers present inside the pump. The impellers have the job of pumping the coolant.

Unfortunately, in engines like this one, the impeller has been made using plastic. Plastic is not a good choice for choosing to work under pressure.

It breaks after a few thousand miles, and that causes various issues with the engine, with the most notorious one being overheating.

Symptoms And Repair

When the B8 S4 engine cannot dissipate heat fast enough, many things can happen, none of which are positive.

Let me outline some of the symptoms which might show up, confirming the presence of the issue:

• Engine overheats rather quickly.
• The coolant level has dropped.
• Engine producing visible steam.
• P3081 check engine code.

These symptoms confirm that you have a coolant problem in the engine.

There is a high chance that it will be the water pump, but you should get a proper diagnosis, regardless. The only thing you can do is get the water pump replaced.

You could go for another OEM pump which will fail after the same period of time, or an aftermarket one, which has been designed to last longer and has been built to be more durable.

3. The Build-Up Of Carbon In The Engine

The carbon build-up is something that can affect any direct injection engine. Although Audi prefers the stratified work injection, the technology is 100% the same.

Regardless, direct injection uses a different method of fuel spraying than simple port injection.

Instead of the intake valves, the fuel is directly sprayed into the cylinders, which not helps in improving performance.

What The Problem Is

So, what could possibly be wrong with this system?

Many of you may not know that there is always some blowback when using direct injection.

The escaped fuel travels through the intake tracts and can settle anywhere, with the highest chance of it stopping at the intake valves.

Although most engines get through their lifetimes without any noticeable impact from the buildup, the V6 engine used in the B8 S4 really gets a drop in performance if there is even a slight blockage.

Diagnosing The Issue

You may be wondering what could be done to confirm if the engine has this issue. Well, there are symptoms that will be automatically noticed.

The most common ones are:

• Poor engine performance.
• The vehicle rough idles.
• Unexpected misfires.

These symptoms do not confirm the presence of the issue, but they will help you in eliminating other possibilities.

Cleaning Up

There is only one way you could go after detecting the presence of carbon buildup in the engine.

You should get the engine walnut blasted. This is something most mechanics offer, so you don’t have to look around too much.

Although the issue pop-ups after 100000 miles of driving the car, it is still recommended to get the blasting process done every 50000 miles.

4. Transmission Failure

This article has finally arrived at the last but the most dangerous problem of all, the failure of the transmission system of the V6 engine.

This issue is so common that it was reported by around 20% of all Audi B8 S4s. This may give you an idea of how widespread the problem is.

The vehicle uses a mechatronics unit that is responsible for controlling the shifting of the engine. It is the one that goes faulty and can only be replaced.

The Issue

This really is a design flaw that the mechatronics unit has been placed in the oil-cooled system.

The fact that it can make contact with the oil may already tell you that it could fail any second.

The failure of the unit causes issues such as hard shifting to and from the first to the second gear.

Other Issues

Unfortunately, the presence of the unit in this location can also spring up other issues.

The most common ones reported by users were:

• Failure of the gearbox.
• The clutch pack could stop working.

As you can see, this one design flaw can cause various issues. Users reported that their engines started exhibiting this problem as soon as 20000 miles of driving the vehicle.

So, this problem is not only extremely dangerous but happens very soon too.

Repair

The failure of the mechatronic unit or any other ones I listed above will require a big check to fix. These parts can only be replaced. The procedure will cost you at least $5000.

Audi did acknowledge this issue and fixed the transmission to a Gen II one in 2012, with the B8.5 model of the car.

What Is The Audi B8 S4 Engine?

The B8 S4 proudly rocks the 3.0L V6 engine, which is also supercharged. The raw power of the engine is 329 HP and 325 lb. ft of torque.

That tells you just how much power it is. It is also more than a decade old, so achieving that power is certainly impressive.

The supercharger in use by the company is an Eaton one. It is one that can get hot extremely fast, so the manufacturer decided to cool it with two intercoolers.

The engine was a downgrade when compared to the B7 in terms of specs, but it almost matched the real-life performance numbers.

Is The Audi B8 S4 Engine Reliable?

The answer to this question is not reliable. The engine is not even close to being the most reliable one on the planet. But it is also far from being the worst.

The engine requires some expensive repairs once anything goes wrong. You might have noticed one thing in the first three problems.

All of the issues are ones that can happen on any engine; it’s just that they happen sooner on the Audi.

But the last one, the transmission failure, is one that deters many buyers from purchasing this beast of a vehicle.

What Cars Use The Audi B8 S4 Engine?

The question contains the answer itself. The V6 supercharger was used in the S4 only.

The company made sure to make it exclusive for this engine so users would not rely on other options with the same engine under the hood.

Audi really made a solid piece of hardware. The performance is amazing, and the reliability is somewhat okay too.

It will certainly give you a driving experience that is definitely worth remembering.

Audi B8 S4 Engine Specs

The Benefits Of Choosing The Audi B8 S4 Engine

The vehicle is an outstanding one; there is no doubt about that. Many users, themselves, crowned the vehicle as to the best on the market.

Let me outline some of the advantages of owning the S4, rocking the V6 beast under the hood:

• The engine is extremely handy, allowing for future upgrade options.
• The ride quality was significantly improved when compared to the predecessor.
• Many issues were fixed in the later models of the vehicle.
• The engine will not require any more work than the issues I listed above.
• The raw horsepower of the engine is enough, so you won’t have to tune it to get more power.

Frequently Asked Questions

Q1. Is The Audi B8 S4 Expensive To Maintain?

Yes, it is! The engine has a yearly maintenance cost of more than $1000.

That is certainly on the upper end of the spectrum. This is something you must keep in mind before going ahead and purchasing the vehicle.

Q2. How Much More HP Can I Get From My Audi B8 S4?

I think you will be thrilled to hear that you can push the 500 HP mark with the appropriate modifications.

The best way to gain this performance boost is by using an ultra-charger. This has been tried and tested, and you are going to love the engine of your vehicle even more.

Q3. How Long Will The Audi B8 S4 Last?

The engine will easily cross the 150000-mile limit. Although it is not a lot, you can certainly push this number to 200000, with the proper maintenance.

If you get all issues fixed on time, then you will be able to reach that mileage.

Conclusion

The S4 is an excellent vehicle. I don’t think there have been any doubts about the engine’s overall performance.

There are some Audi B8 S4 problems, which should definitely be considered before purchasing the engine. Although most of them are cheap to repair, the final one can cost you a lot.

If you really want my recommendation, then I would advise going for the B8.5, the facelift model of the vehicle.

The manufacturer fixed many issues, including the transmission ones, so it is more reliable than the one you have chosen.

But, if you are willing to pay the costs, then you will have a fantastic driving experience.

Resources:
1. https://vwtuning.co/audi-b8-s4-common-engine-problems-reliability-issues/
2. https://blog.ecstuning.com/common-problems-with-the-audi-b8-b8-5-s4/