So you want a big fat V10 German diesel in the good old Touareg or Phaeton. We can’t blame you, they are awesome! But there’s one thing, these V10 TDI engines from Volkswagen are only awesome when they work. Otherwise, they can be a legit nightmare.
Having proper research done before you buy a big V10 diesel powered car is always a smart idea. You just don’t want to end up in a money pit full of problems. And trust us, when it comes to these big engines, there are a lot of really expensive repairs that will cost you an arm and a leg to sort out. Luckily, we are here to help you out.
First, we are going to cover the basic V10 TDI engine specs, then we shall discuss in-depth the Volkswagen V10 TDI engine problems, as well as the models which had this V10 engine. So, without further ado, let’s dive into the article.
Basic VW V10 TDI Engine Specs
The V10 is something like a legend and also a myth in the car community. Everybody knows and talks about these engines but no one has seen one in person.
This was mainly due to the fact that these engines were produced in very small numbers. Not that you cannot find one. But the numbers were really small compared to other V8 engines that VW and Audi made at the same time.
This mammoth of an engine was introduced in 2003 and was produced until 2008 when it was discontinued because of the lack of popularity of these engines as well as the high emissions and poor fuel economy that it had.
There was also an even bigger V12 TDI that VW introduced at the time and this engine had also a similar fate to the V10.
The V10 was in general made out of two R5 2.5 TDI engines combined together. Many of the components between them were shared as well. Now let’s cover the basic specs of the Volkswagen V10 TDI engine.
- Configuration: V10
- Displacement: 4.9L (4921cc)
- Cylinder Bore: 81 mm
- Cylinder Stroke: 95.5 mm
- Valvetrain: SOHC, 2 valves per cylinder
- Compression Ratio: 18.5
- Turbocharger: Yes
- Horsepower: 313 – 350 hp @ 3,750 rpm
- Torque: 750 – 850 N-m (553 – 627 lb-ft) @ 2,000 rpm
Common Volkswagen V10 TDI Engine Problems
Common Volkswagen V10 TDI engine problems include:
- Center Bearing Failures
- Transmission Failures
- Fuel Filter Problems
- Tandem Fuel Pump Failures
- Turbocharger Failures
- Tandem Pump Failures
- Water Pump Failures
- EGR Problems
- Alternator Failures
Now that we covered the common Volkswagen V10 TDI engine problems, let’s move on and learn more about each of these issues in-depth and understand more about them when they appear, as well as the symptoms they produce in the following chapters.
Center Bearing Failures
Now let’s start with a common problem with this engine and this is the problem with center bearing failures of the driveshaft, also known as prop shaft.
This engine produces so much torque that the driveshaft is one of the most common failure points. They tend to fail all the time.
The weakest point on the driveshaft is the center bearing which tends to fail most often. This is not an engine problem, as you can tell. But we decided to add the issue since the problem occurs on every one of these V10 engines.
Luckily, this is one of the most inexpensive problems that can happen during your ownership of this V10 TDI engine.
Another common failure point in this engine is the transmission. This component fails very typically in the same fashion as the crankshaft.
Another non-engine-related problem but still, it happens as a consequence of the engine work. Big torque equals a lot of stress on the transmission which results in early failure or at least problems. This is especially common on cars that have been launched and abused constantly.
It goes without saying that doing repairs or replacing the transmission is incredibly expensive.
You will highly likely have to pay $6,000 or more to replace the unit on this engine. And this is not a small amount of money, considering the actual value of the vehicle is not that big.
This is why we often advise that you test the transmission thoroughly since this component can cost you an arm and a leg to fix it.
If you’re buying a V10 Touareg or Phaeton, look for cars that were driven by calm drivers, not some young guy who kept it for a month and trashed it on every street corner.
Fuel Filter Problems
Now let’s move on to the actual Volkswagen V10 TDI engine problems. And one of these problems is the fuel filter issue.
There are two massive fuel filters on this engine that are located in the rear end of the valley next to the firewall.
These two filters are placed together, and they visually resemble an oil filter rather than your typical tiny fuel filter.
Since this is a massive engine, it needs to have these filters to work properly. And what can happen is that these filters can clog up and cause problems like engine surging, engine misfires, and other similar issues.
In the video above, you can check how these filters are replaced. They are in fact a very easy DIY job that any beginner can do.
Tandem Fuel Pump Failures
The second most notorious problem that happens on this engine is the tandem fuel pump failure that can happen and cause similar symptoms to the fuel filter that we previously noted.
There are two fuel pumps. One on each cylinder head and they work together in tandem. They are located behind the cylinder head. Right between the engine and the firewall.
And in order to remove these pumps, you will have to drop the whole subframe. This means that both the engine and transmission will need to come off because there is simply no room to work on the engine while it’s in the engine bay.
Whenever these pumps fail, you will experience symptoms like fuel leaks, check engine light, limp mode, and misfires.
The only way around this problem is to replace the tandem pump and this can be very costly.
Turbocharger failures are also noted on this engine. This engine is using two Garret turbochargers, one per bank.
And both of these turbochargers are mounted on the bottom sides of the engine. And if you guess right, removing one of them will again mean that you will have to drop the subframe.
These turbochargers go out every 150,000 miles or so. Whenever the turbo fails, you will start to hear whistling noises and a drop in performance.
We advise that whenever you do this service, it is much better to replace both turbos at once if the other turbo is also somewhat damaged. It might be more costly but you will not pay thousands of dollars to drop the engine again.
Water Pump Failures
Water pumps also commonly fail on these engines. But what is good is that they do not require the removal of the engine for their replacement. Which is good.
The water pump is mounted at the front of the engine and is easily accessible. Even a beginner mechanic can do this replacement.
Symptoms associated with the water pump are noises that the pump will start to make, coolant leaks, and overheating issues are also common.
EGR problems on these engines were also noted. The EGR is the exhaust gas recirculation system. This system has a special task to get some of the exhaust gasses and redirect them into the intake manifold.
This engine is using an EGR system that is very complex and has a lot of routing. What can happen is that these EGR valves can malfunction if not cleaned well.
This will make the EGR valve inoperable and whenever this happens, you will start to experience strange symptoms like the check engine light, loss of power, limp mode, and other running issues.
The solution to this problem is to completely replace the EGR valve with a new one if you want to resume proper engine work.
Alternator failures are also common on this V10 TDI engine. So, why is this the case?
Well, this alternator is not your typical alternator, the alternator in this engine is very tightly packed inside the valley of the V10 engine.
And inside the valley, there is a lot of debris and heat that can easily damage the alternator.
Glow Plug Harness Failures
And the last problem on our list is the glow plug harness failures. These are the wiring harnesses that go to the glow plugs.
There are a total of 10 glow plugs on this engine since it is a V10. These harnesses can fail on higher mileage engines.
They mainly fail because they are exposed to heat and they are also made out of really cheap plastic. The only way around this problem is to replace them.
Fuel Injector Problems & Other Age Related Issues
Since this is a V10 engine, there are 10 fuel injectors and as these cars age and cover huge mileages, the fuel injectors are bound to need replacement. If you decide to replace them with refurbished ones, they usually cost between $125 and $220 per injector.
That means you can expect to pay around $1500 for the injectors alone, and you can add the price of labor on top of that as well.
Keep in mind that there are also numerous other things you can expect to replace, considering the age of this car. Simply replacing all the seals and deteriorated tubes on this engine can cost you up to $2000.
Which Models Have The V10 TDI Engine?
This engine was included in the following vehicles.
- 2002 – 2008 VW Touareg V10 TDI
- 2003 – 2007 VW Phaeton V10 TDI 4Motion
What Are The Common V10 TDI Engine Problems?
Common problems with this engine are the driveshaft support bearing failure, transmission failure, fuel filter problems, fuel pump failures, alternator failures, turbocharger failures, and glow plug harness failures.
Is The VW V10 TDI Engine Reliable?
This engine is pretty reliable, but there’s still a lot that can go wrong when you’re taking care of 10 cylinders. VW simply knows how to make diesel engines, especially during this era when there were no complex emissions devices. The only drawback of these engines is the expensive maintenance. For every major engine work, the whole engine has to be dropped and this is really expensive.
If you’re seriously considering buying a V10 Touareg or Phaeton, make sure you have money ready for some hefty repairs. It helps a lot if you know how to handle small repairs on your own.
If possible, buy a car with a rich maintenance history and make sure the records of those repairs are present.