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The Audi 3.0T V6 24v engine (EA837) made its debut in the C5 A6 back in 2009 and is still being produced today. There are two generations of the 3.0 TFSI. It is warranted as one of the most reliable S model engines Audi has ever produced. The engine features an Eaton supercharger with 24 valves plus Audi’s patented FSI technology. As you can imagine, there are many engine codes for this engine: CAKA, CAJA, CCBA, CMUA, and CTXA.
This incredible supercharged engine puts down an impressive 268hp – 349hp & 295lb-ft – 347lb-ft of torque. The wide variance of these numbers is due to detuning on certain models. The lower end of the power scale can be found in the A4, A5, or Q5 and the upper end of the power scale can be found in the SQ5. This is one mean engine that has a lot of tuning potential. We have seen some 3.0T’s running sub 11 second quarter miles @ 134.93mph.
Audi’s 3.0T Applications
Common Audi 3.0T Engine Problems
- Ignition coil and spark plug failure
- Premature thermostat and water pump failure
- Carbon buildup
- Excessive oil consumption
- Oil pressure switch failure
- Crankcase vent valve failure
- Motor mount failure
Before getting into more details on the common problems seen, please make sure any of the replacement parts fit your specific vehicle. As you can see, there are MANY applications this engine is found in.
1. Ignition Coil and Spark Plug Failure
Spark plugs need electricity to create a spark in the combustion chamber. That electricity comes from ignition coils. Ignition coils get low voltage from the battery and transform it into higher voltage the spark plugs need to function. Without functioning plugs or coils, the engine will have misfires or may not even start.
Ignition coils and spark plugs are exposed to high heat since they are found in the cylinders. This and modified engines are the main reasons for coils and plugs failing. Ignition coils typically go out every 60,000 – 80,000 miles, so you will probably go through at least two sets of coils and plugs.
Symptoms of Ignition Coil and Spark Plug Failure:
- CEL/MIL illuminating
- P0300 – P0306 fault codes on an OBD-II scanner
- Engine misfires
- Sluggish engine performance
- Rough idle
- Engine stalls
Ignition Coil and Spark Plug Replacement Options:
We highly advise replacing all of the ignition coils and spark plugs if there is one bad ignition coil to ensure fewer headaches with misfires down the road. If you happen to have modified the engine, then we would advise going with cooler spark plugs and aftermarket ignition coils because the factory ones will not sustain the increased power. If you know where the coils and plugs go, this is a rather straightforward DIY, but make sure the spark plug gap is correct for the specific engine. A mechanic will likely charge around $500 to replace both.
2. Premature Thermostat and Water Pump Failure
We’re gonna combine the thermostat and water pump into one because they are crucial to an engine’s cooling system. A thermostat regulates the coolant that is recycled back into the engine and how much coolant is cooled by the radiator before being recycled. A water pump maintains the flow of coolant from the radiator to the engine and back.
The first-generation 3.0T’s had thermostats that were prone to sticking closed and water pumps leak from the bearing wheep holes. If either of these happens to fail, the engine can overheat quickly because of the lack of coolant being pushed through the engine. In Audi’s and Volkswagen’s, both the thermostat and water pumps will fail at least once in the vehicle’s lifecycle.
Symptoms of Thermostat or Water Pump Failure:
- Low engine coolant/antifreeze indicator illuminating
- Engine overheating
- Limp mode
- Coolant leaking on the ground
- Sweet smell coming from the engine
- Erratic temperature readings
Thermostat and Water Pump Replacement Options:
When either, the thermostat or water pump goes out, we advise replacing both because generally, these go out at the same time. Given the position of the water pump and thermostat on the 3.0, this isn’t the worst DIY and it would save you some mod money. Expect a mechanic or dealer to charge around $1,000 to replace both the thermostat and water pump.
3. Carbon Buildup
Carbon buildup is a common problem in many modern engines nowadays with direct injection technology. Direct injection shoots fuel directly into the cylinders, therefore the ports and valves don’t get cleaned by the fuel and other detergents. This will eventually, 60,000 miles, lead to carbon buildup in the intake valves and ports.
When carbon buildup occurs, there will be soot found in the valves making the engine harder to “breathe”. Believe it or not, carbon buildup can severely dampen the engine’s performance. It will occur more on vehicles that drive short commutes regularly because the engine doesn’t get hot enough to burn off the caked-on buildup. However, if a vehicle has longer commutes, there will be less buildup naturally.
Symptoms of Carbon Buildup:
- Cold start misfires
- Sluggish engine performance
- Engine knocks
- Poor fuel economy
Ways to Prevent Carbon Buildup:
- Replace spark plugs and ignition coils regularly
- Use the highest quality fuel as possible (93+ Octane)
- Get more than normal oil changes
- Manually clean the intake valves every so often
- Run the engine hard regularly (30mins above 3500RPMs)
- Get walnut blasted every 60,000 miles
- Using Sea foam or another chemical to clean out and prevent buildup
4. Excessive Oil Consumption
Excessive oil consumption isn’t an extremely common problem except for on the first generation 3.0T’s. As it sounds, this means that the engine is consuming more engine oil than what is optimal from Audi. If you happen to notice the oil pressure light illuminating more often than it should be, we would advise taking it to the shop to get a compression test. This will indicate how much pressure the engine makes and if there happens to be a leak.
The main causes of excessive oil consumption include PCV valve failure or piston rings that are too thin. 9/10 out of 10, the cause of excessive oil consumption is going to be a faulty PCV valve. If excessive oil consumption is ignored for an extended period of time, this could lead to costly repairs of $5,000 or more.
Symptoms of Excessive Oil Consumption:
- Oil deposits present
- Blue smoke coming from the exhaust
- Low oil pressure indicator illuminating more than normal
- PCV valve failure – P0507 or P0171 fault codes
- Metal shavings in the oil pan
5. Oil Pressure Switch Failure
This is one of the first oil pressure switch problems we have heard about when it comes to Audi engines. This problem tends to occur in early first-generation 3.0T’s. An oil pressure switch, or often referred to as an oil pressure sender, is installed in the oil circuit and it monitors the oil pressure and is responsible for turning on and off the oil pressure indicator. It is known as a protection device and if it fails, the engine and you will get mixed signals with oil, which is dangerous for the reliability of an engine.
The oil pressure switch in early 3.0T’s fail because it is an older style switch. Again, this is the first engine we’ve heard where this can be a potential problem, so normally oil pressure switches should last through a vehicle’s lifecycle.
Symptoms of Oil Pressure Switch Failure:
- Oil pressure light illuminating
- Fault code P1648B present
- Oil pressure light blinking
- False reading on the oil pressure gauge (typically very high or 0)
- Oil leaking from the switch
- Engine overheating
- Limp mode
Oil Pressure Switch Replacement Options:
When you suspect the oil pressure switch has failed or is failing, it is important to replace it ASAP because an inaccurate oil reading could be costly to an engine. Although it is in a tricky position, we advise doing this DIY on a cold engine because it is under the supercharger. It’s a cheap part that shouldn’t take any longer than an hour or two to replace. A mechanic would charge around $150 mostly due to labor costs.
6. Crankcase Vent Valve (PCV Valve) Failure
Crankcase vent valves (CCV) or what is more commonly called the PCV valve is no stranger to failing in Audi’s and Volkswagen’s. A CCV’s main purpose is to control emissions. It carries the engine’s gases into the combustion chamber to be burned off before exiting the engine. It also prevents gunk from building up in the crankcase.
The main reason these fail is due to being stuck closed or the diaphragm within the housing failing. When it does fail, it can lead to excessive oil consumption and poor engine performance. A CCV or PCV valve will likely go out every 60,000 – 80,000 miles, so you will more than likely have to change it out at least twice in a vehicle’s lifecycle.
Symptoms of Crankcase Vent Valve Failure:
- Lean AFR conditions
- White smoke coming from the exhaust
- Excessive oil consumption
- Rough engine conditions
- Engine misfires
Crankcase Vent Valve Replacement Options:
If the crankcase vent valve goes out or is stuck in the closed position, the only option is to replace the entire unit. Since it sits underneath the superchargers compressor, it is more difficult to get to than the 2.0T TSI engines, but it isn’t too difficult with the proper tools. A mechanic will likely charge around $400 to replace a CCV.
Crankcase Vent Valve Replacement: Purchase Here
DIY Difficulty: Easy
7. Motor Mount Failure
Motor mounts are common problems in higher-end Audi engines. They are components that hold the engine in place and dampen any engine vibrations while the vehicle is idle or in motion. Without functioning motor mounts, the driving experience will be rough with clunking engine noises.
The main reason these motor mounts fail is due to hydraulic fluid leaking out of them. If ignored this could cause engine damage since the engine will be bouncing around more than normal.
Symptoms of Motor Mount Failure:
- Heavy engine vibrations
- Banging or clunking noises from the engine
- Movement of the engine while driving
- Low hydraulic fluid
- Rocky startup
- Misalignment of the engine in the engine bay
Motor Mount Replacement Options:
When motor mounts fail, regardless if it is only the right or left, we highly advise replacing them all. The reason being is because they typically go out around the same time. There are two options: replace them with OEM mounts or replace them with aftermarket mounts. We advise the aftermarket route because they SHOULD last longer than the OEM mounts. There have been consumers that aren’t happy with some aftermarket companies, so they chose to do OEM over aftermarket. This certainly is not an easy DIY and will take some time. A mechanic would likely charge around $1,000 depending on labor charges.
Audi 3.0T Reliability
Audi’s 3.0T engine is known to be one of the most reliable engines to date, although the laundry list of problems above may tell you otherwise. Aside from the common water pump and thermostat leaks in the early 3.0T’s, this is a solid engine. Believe it or not, 3.0T is one of the most sought-after engines in used Audi’s today. Make sure to follow all of the maintenance schedules to a tee and just take care of the engine to get the most out of it. We have seen many of these hit the 200k mark without any major engine issues and are still going. Let us know your experience with Audi’s 3.0T engine in the comments below!
Also, if you would like to read more Audi content, here is our write-up on “The 5 Most Common Audi 4.2 V8 Engine Problems.”