Audi’s 2.7T twin-turbo (biturbo) V6 30v DOHC engine debuted in the B5 S4 in 1997 and ended production in the B6 A4 in 2003. This is not a very long-lasting engine from Audi, but there are still plenty of these on the road today.
The engine features twin turbos and puts out anywhere from 227hp – 376hp and 229lb-ft – 325lb-ft, where the higher end of this range is found in the RS4. These engines have a love-hate relationship in the Audi community. We’ve seen some that last all the way to 300,000 miles depending on maintenance.
Before going into this 2.7t common problems guide, PLEASE make sure the parts and DIY guides listed apply to your specific vehicle! Let us know in the comments if you need help looking for parts and guides and we will assist in any way we can!
Audi 2.7T Common Problems are Applicable for:
B5 S4 – Engine Code: AGB/APB/ASJ/AZB
B5 RS 4 – Engine Code: ASJ/AZR
B5 A4 – Engine Code: AGB/ASJ/AZB
C5 A6 – Engine Code: AJK/APB/ARE/AZA
C5 A6 Allroad – Engine Code: APB/ARE
B6 A4 – AZR
Common Audi 2.7T Engine Problems
- Ignition coil pack and spark plug failure
- Premature water pump failure
- Timing belt & Tensioner failure
- Brittle vacuum system
- Poor camshaft seal
- CV boots & control arm failure
1. Ignition Coil Pack & Spark Plug Failure
Ignition coil pack failure is common in many turbocharged engines. In the 2.7t, there will be 6 coil packs, one for each cylinder. Within the coil pack is a spark plug that can also fail. If your engine happens to have one faulty coil pack or spark plug, more than likely it will experience misfires. If multiple of either coil packs or spark plugs go out, your vehicle may not start.
The main reason coil packs and spark plugs fail is by normal wear and tear. You will likely only experience either of these going out once or twice throughout the vehicle’s lifetime unless your vehicle is tuned. If your vehicle is tuned or you are wanting it to be tuned, expect to change these multiple times unless you go the aftermarket route and get colder units.
Symptoms of Coil Packs/Spark Plugs Failure:
- Engine misfires (P0300, P0301, P0302, P0303, P0304, P0305, P0306 Fault Codes)
- Check Engine Light (CEL) Illuminating
- Rough idle
- Rough engine performance
- Engine not rolling over
Coil Pack/Spark Plug Replacement Options:
If you happen to experience the symptoms listed above, we highly advise getting an OBD-2 scanner to see what faults your engine is getting. If you do happen to have a faulty ignition coil pack, we highly recommend replacing them all. Yes, it may be more expensive, but it will be better in the long run. With the proper tools, this is not a difficult DIY. If you are wanting to take your vehicle to the shop for this service, look to spend around ~$200 – $300.
DIY Difficulty: Easy
Coil Pack Video DIY Guide: https://www.youtube.com/watch?v=zEOd8rAdvfk
Spark Plug Video DIY Guide: https://www.youtube.com/watch?v=VzhtoEHNFHg
Spark Plug Written DIY Guide: https://autodiyonline.com/audi-diys/audi-a6-diys/audi-a6-2-7t-1997-2004-spark-plugs-replacement-diy/
2. Premature Water Pump Failure
Unfortunately, this is probably one of the most common problems in a lot of Volkswagen’s and Audi’s due to the way these were built out of the factory. The role of a water pump is to transport coolant from the radiator to the engine to make sure the engine temps are at optimal levels. With a failing or failed water pump, your vehicle will more than likely overheat until you put more coolant in or replace the water pump as a whole. If you are experiencing this, we advise taking action immediately as more costly damages can occur if ignored.
The two main reasons water pumps can fail are: normal wear and tear or the internals (bearings and seals) weaken causing leaks. Generally speaking, if fluid levels are maintained, water pumps SHOULD last anywhere from 60,000 – 90,000 miles. With that said, you will likely have to replace a water pump at least once throughout the vehicle’s life cycle.
Symptoms of Water Pump Failure:
- Engine overheating
- Coolant leaking
- Steam coming from under the hood
- Loud whining noise in the engine bay
Water Pump Replacement Options:
Usually, when a water pump goes out, it is a safe bet to replace the timing belt as well since water pump replacement requires removing the timing belt. But if you were just wanting to replace the water pump, it isn’t extremely difficult and would require a few hours if you know your way around an engine. If you are planning to take it to a shop, you would be looking at a bill of about ~$500 if you are only wanting to do the water pump.
OEM Water Pump Replacement: https://audi.us/3w74XKr
DIY Difficulty: Intermediate
DIY Guide: https://www.youtube.com/watch?v=ZiZvO1UOOu8
3. Timing belt failure
The timing belt in Audi’s and VW’s don’t seem to be made the best out of the factory either. As you can see below, the timing belt plays a huge part inside of the engine. It not only synchronizes the rotation of the crankshaft, the camshaft, and the cylinder heads, but it also drives the water pump.
If a timing belt does happen to break, you could have catastrophic engine damage. We recommend changing the timing belt every 75,000 miles as preventative maintenance. With that said, you should only realistically have to change a timing belt and the main components 2 or 3 times throughout the vehicle’s lifetime.
Symptoms of Timing Belt & Tensioner Failure:
- Engine not starting
- Ticking noise coming from the engine
- Engine misfires
- Rough idle
- Lack of performance
Timing Belt Replacement Options:
When performing a timing belt service, whether it be a repair or preventative, we highly recommend replacing the water pump, thermostat, tensioners, and valve cover gaskets & cam chain tensioners. The reason we say this is because all of those listed usually go out around the same time, which is 75,000 – 90,000 miles. If you are just wanting to do the timing belt replacement, which we don’t recommend it isn’t the easiest DIY, but it is possible. If you were to take your vehicle into the shop for this service, you will be looking at nearly ~$1,000 – $1,500.
OEM Timing Belt Replacement Kit: https://bit.ly/3qEQfcz
DIY Difficulty: Intermediate
Written DIY Guide: https://bit.ly/3dvte6x
Video DIY Guide: https://www.youtube.com/watch?v=Cdh2kuYQIds
4. Vacuum System Leaks
When we say “vacuum system”, we are mainly referencing the vacuum hoses. Due to these engines being made in the late 90’s and early 2000’s, you will more than likely come across brittle vacuum hoses. If you haven’t changed the vacuum hoses on your current 2.7 or prospective 2.7, we would advise doing so to prevent any future vacuum leaks. A simple little hole in a hose, can drastically change the way your vehicle’s performance and function.
The function of a vacuum system in a vehicle is to create suction and bring air into the engine. It also controls the RPMs of an engine. Without a properly functioning vacuum system, your vehicle will not be able to run. There is a diagram below for the vacuum lines we are referencing.
Symptoms of Vacuum System Leak Failure:
- Hissing sound coming from the engine
- CEL Illuminating with P2279, P0421, P0491, or P0492 fault code
- Sporadic idle
- Engine performance loss
- Engine stalls
Vacuum System Replacement Options:
If you don’t know your way around the engine, it would be best to take it into a shop to replace the brittle vacuum lines.
OEM Vacuum System Hose Replacement: https://bit.ly/3wcqfqf
DIY Difficulty: Difficult
5. Poor Camshaft Seal
An often overlooked part in the 2.7t engines, is the camshaft seal. All it is is a round oil seal that is located in the cylinder head. As you can imagine, it seals the end of the camshaft between the cylinder head and the valve cover gasket. For some reason on this engine, they weren’t made to be as durable as they should be, which is why this is a lot more common. If these seals start to wear out, oil can leak from the engine, which is never a great outcome if unattended.
The main reason these round seals fail is rapid wear and tear from the OEM seals. If you are a current Audi 2.7t engine owner and haven’t changed these yet, we would highly recommend doing so. If you are looking to get a 2.7t, we advise asking if these have been changed as it will ease your mind in the long run. You should only have to replace these once and they should be good for the rest of your vehicle’s life cycle.
Symptoms of Poor Camshaft (Gasket?) Seal:
- Visible oil leakage on the engine
- Smoke from the engine
- Engine overheating
- CEL illuminating
Camshaft Seal Replacement Options:
If you know your way around an engine, this is not the worst DIY. We would probably advise doing it yourself IF you know what you are doing because if you were to take it to a shop your bill would be 90 – 95% labor since the seal itself is so cheap. But overall you would be looking at around $400.
OEM Camshaft Seal Replacement: https://audi.us/3qBsz91
DIY Difficulty: Difficult
DIY Guide: https://www.youtube.com/watch?v=A5GfF28Lf5M
6. CV Boots & Control Arm Failure
You may be wondering why this made it on the list because it isn’t technically an engine problem, but we thought it was important to include it because it is a very common problem in B5 S4’s. For some reason, the boots and control arms out of the factory were not built to be very reliable.
CV (Constant Velocity) boots cover the CV joints and ensure the joints stay lubricated and dirt-free. Unfortunately, these boots commonly tear which slowly causes the joints to fail. Control arms are very important in the suspension system because they allow the driver to steer the car. If you are experiencing any of the symptoms below, you will want to act on it fast as these parts are equally important when it comes to transmission and steering.
Symptoms of CV Boot or Control Arm Failure:
- Grease leak on the inside of the wheels
- Vibrations from the axel
- Clicking/clunking noise from the axel on turns
- Steering wheel vibration
- Steering wandering
CV Boot & Control Arm Replacement Options:
If you have some sort of a lift, this DIY is a lot more manageable. However, if you don’t have any kind of lift, we would advise having a dealer do it because it is a pretty difficult DIY. To repair just the front or rear boots, you would be looking at around $700 at the shop. If you were needing to replace any control arms, you would be looking at $400/control arm.
CV Boot Kit Replacement: https://www.ecstuning.com/Audi-B5_S4–2.7T/Drivetrain/Axles/CV/Boot/
OEM Control Arm Kit Replacement: https://www.ecstuning.com/Audi-C5_A6-Quattro-2.7T/Suspension/Control_Arm/
DIY Difficulty: Difficult
CV Boot DIY Guide: https://www.youtube.com/watch?v=UAOF5oQnIFE
Control Arm DIY Guide: https://www.youtube.com/watch?v=wKJ9-EMF9-k
Great Control Arm Thread: https://www.audiforums.com/forum/audi-a6-9/total-control-arm-replacement-2-7t-96380/
Audi 2.7T Engine Reliability
Even though it seems like there is a long list of issues with the Audi 2.7t engine, we have seen some stage2 and stage3’s last until 300,000 miles. With that said, it all depends on how well maintained the vehicle is. This is not to say that all of these engines will last that long, but have the capability to.
What is your experience with Audi’s 2.7t Engine? Let us know in the comments below.
Also, if you want to check out more Audi content, here is our write-up on the common problems with an Audi S4 (B8).