The B8 replaced the B7 in 2008 model year A4s and remained in production until 2016. The B8 A4 lineup included a sedan, an Avant/wagon, an Allroad Quattro (4WD), and a sedan explicitly tailored to the Chinese market (the A4L). Different external and internal components of the B8 were updated in 2012.
The 2.0L TFSI and 1.8L TFSI were the most common gasoline engines in the A4 B8, while the 2.0L TDI was the most common diesel engine.
The Audi A4 B8 is, in general, a rock-solid automobile. However, these automobiles often experience a variety of engine- and non-engine-related issues.
Audi A4 B8 Common Problems
- Clogged Fuel Injectors / Leaking Fuel Injectors
- Water Pump Failure
- Defective Power Steering Hose
- Extreme Oil Consumption
- Carbon Buildup in Intake Valves
1. Clogged / Leaking Fuel Injectors
In the B8 A4, fuel is sprayed directly into the cylinders using fuel injectors. Fuel injectors may become clogged, filthy, and leaky over time. Insufficient power is delivered to the engine’s cylinders when a fuel injector fails. Thankfully, having every injector malfunction simultaneously is relatively rare. Typically, these components go down one by one, but a single faulty injector may significantly impact performance and handling.
Injectors may fail in two ways: by being stuck open or closed. Either no gasoline will be pumped into the cylinder, or there will be too much. This may occur often or seldom, but it will lead to misfires either way.
Signs Your A4 Fuel Injectors Have Problems
Is your car’s engine straining to get up and running? Poor idling, misfires or a sluggish loss of power could be signs that it needs help. Additionally, if you notice fuel dripping from the bottom of your A4’s engine and some pesky fault codes (P0300-304) popping in for an unexpected visit – these might be red flags worth looking into! If all else fails, evaluate how much mileage you’re getting out of each trip; poor fuel economy may prove the diagnosis right.
Fuel Injector Failure Diagnosis
A faulty water pump, spark plugs, faulty ignition coils, and so forth may produce similar symptoms. Because injectors are expensive and difficult to repair, you should check the fuel rail’s fuel pressure before replacing any injectors.
Faulty ignition coils are another potential cause of the P0300-P0306 error codes. Ignition coils boost a vehicle battery’s voltage to start the combustion chamber. A single defective ignition coil may cause misfires. It will be difficult, if not impossible, to create an automobile if many ignition coils malfunction. When one ignition coil fails, it’s best to replace them so that the ignition system always has new parts.
Read this guide on diagnosing faulty fuel injectors
2. Water Pump Failure
The water pump is the weakest and most likely component to break on the B8 A4. Unlike other Audi models, the original equipment water pump was made of plastic, not metal. The high temperatures in the engine compartment may cause the plastic casing of the water pump to fracture over time, allowing coolant to seep out and ultimately causing the pump to fail.
Another vulnerable area is the gasket that seals the water pump to the thermostat. After some time, gaskets become brittle and easily shatter or deteriorate. When this occurs, the gasket’s ability to prevent leaks is reduced.
There have been cases of the water pump breaking down twice or thrice before the vehicle reached 100,000 miles. Because of this, a class action lawsuit was filed for all owners of the A4 manufactured between 2009 and 2014 and equipped with a 2.0L engine.
Signs of a failing water pump
If your Audi A4 B8 leaves you high and dry, its water pump might be in trouble. Look out for tell-tale symptoms like a drippy coolant leaking onto the garage floor or fault codes related to low coolant levels – not to mention potential engine overheating issues! Rust, corrosion, and build-up around the pump are warning signs that it’s time for repair so act fast before things get too hot to handle!
Options for Replacing a Water Pump
Audi announced a recall for model years 2013-2016 A4, so owners who haven’t had their cars serviced may be eligible for a replacement.
Aluminum water pumps are superior to the Genuine Audi water pump and should be used wherever possible. Compared to plastic components, aluminum is far more durable and reliable; thus, it can be relied upon to keep the housing from cracking.
The fix is simple enough that you could probably do it in three to four hours on your own if you wanted to.
3. Defective Power Steering Hose
Audi A4 drivers have complained about speed wobble and severe vibration at both slow and fast speeds. Audi discovered that hard-braking drivers were at increased risk for the issue since a malfunctioning power steering hose was a common cause.
Early B8 models are particularly susceptible to this issue. Audi has issued a recall to replace the power steering hose and a Technical Service Bulletin (TSB) 2020332/4 to address this problem. This problem may often be remedied by cleansing and changing the power steering fluid, even if the hose must be replaced. Furthermore, unbalanced wheels may contribute to a speed wobble issue.
4. Extreme Oil Consumption
Numerous B8 A4 drivers have complained that their vehicle uses more oil than usual. Some A4 drivers say they have to add a whole quart of oil every thousand or two thousand miles, while others’ vehicles’ motors have no such problems.
A class action lawsuit was launched in 2012 on behalf of 129,000 Audi owners over the vehicles’ high fuel usage. Initially, Audi believed that a fault caused the issue with the pistons & rings; however, they eventually discovered a solution by replacing the engine breather and upgrading the software. The class action case increased Audi’s warranty coverage from 6 years/70,000 miles to 8 years/80,000 miles, plus an additional year/10,000 miles.
If your vehicle uses an abnormally large amount of oil, you may keep topping it up whenever it gets low or get it serviced. Consumption levels above the average shouldn’t degrade dependability over time.
5. Carbon Buildup in Intake Valves
Direct injection is standard on all new Audi engines. Each cylinder in a direct injection engine has its fuel injector, which sprays gasoline directly into the cylinders. Fuel is provided via the intake valves of a machine that does not use direct injection or one that uses port injection; as a result, the intake valves experience a highly pressured fuel flow that maintains them clean and avoids muck buildup.
If fuel is sprayed into the cylinders rather than pumped via the intake valves, the intake valves are at risk of being clogged with oil blow-back. In the end, carbon deposits form on the intake valve. As carbon deposits accumulate in the intake valve, the air that can pass through it decreases.
Signs of Carbon Accumulation on an A4
- Decrease in efficiency/bad handling
- Trouble starts, stuttering and idling.
- Misfires
What Products Work Best for Removing Carbon From Audis’
Walnut blasting your Audi’s intake valves is the most popular and efficient approach to minimize or remove carbon buildup. When you apply the technique of “walnut blasting,” you force crushed walnut bits into your intake valves using a compressed air stream. This method will remove all the carbon deposits, allowing for optimal ventilation.
Blasting walnut requires specialized equipment and might take up to six hours. It’s not simple for even a seasoned do-it-yourselfer, so taking it to a technician is the safest option. However, independent repair shops can execute the job for less than $1,000, whereas Audi stores would charge about $1,500.
Every 50,000 or so miles, give your engine a walnut blast to keep it running smoothly.
Reliability of the Audi A4 B8
The A4 B8, despite the issues above, may be a dependable vehicle if properly maintained. Audi has recalled and fixed most of the faults mentioned above; however, the protection plan on components such as the water pump may soon expire on early B8 models.
