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The Volkswagen W8 engine, often badged as simply “W8”, had a short life span, however, it was very innovative at the time. It was produced from 2001-2004 and only appeared in approximately 11,000 B5.5 Passat 4motion. Put best, the W8 or WR8 was a great way to package a V8 into a smaller space. It was actually voted for the “best technical innovation” during its time in production. With that being said, it is an absurdly complex engine that isn’t the most reliable, especially since Volkswagen discontinued it after 3 years.
The VW W8 engine includes two narrow-angle VR4 engines mounted at approximately 72 degrees from each other on a common crankshaft, which forms a “W” shape. The “W” shape is how this engine got its name, WR8. It had 2 engine codes: the BDN and BDP. It was an eight-cylinder 4.0L naturally aspirated engine that put down 271hp and 273lb-ft of torque. Although the power outputs were quite lower than competitive V8 engines, the VW W8 was praised for its smoothness.
Common Volkswagen W8 Engine Problems
Before jumping into the common problems, we want to mention that it seems the 2002 W8’s tend to have more issues than the later 03-04 versions. This is normal because as engines age, variations are made to make them more dependable, for example, look at the 2.0T Volkswagen has today. Also, if you happen to own a VW W8 engine and are looking at the replacement parts listed below, MAKE SURE IT FITS!
- Cam adjuster failure
- Torque converter failure
- Faulty fuel gauge senders
- Excessive oil consumption
- Catalytic converter failure
1. Cam Adjuster Failure
Also known as the camshaft phaser, this is the most common issue when it comes to the W8 engine. On this engine, there are 2 sets of cam adjusters, totaling 4 individual adjusters. A camshaft adjuster works with the camshaft to control valve timing. Without functioning cam adjusters, the engine will run rough and the engine timing could potentially be off.
Unfortunately, this is just a design flaw by the Volkswagen Group, so if your W8 camshaft adjuster hasn’t failed, you may want to consider taking it into the shop to get it replaced. These parts should last throughout the lifecycle of a vehicle, however, as stated above, the factory adjusters on the W8 were defective.
Symptoms of Cam Adjuster Failure:
- Check Engine Light (CEL) or Malfunction Indicator Light (MIL) illuminating with fault codes P0021 or P0011
- Rough idle
- Engine rattle
- Engine timing off
- Cam adjuster screen clogged
Cam Adjuster Replacement Options:
As stated above, there are 4 individual cam adjusters and they are not cheap to replace. We’ve seen customers pay up to $5,000 to replace 2 sets of cam adjusters because the whole engine has to be removed and stripped down. We would not advise performing a DIY unless you are REALLY confident with these engines.
DIY Difficulty: Difficult
2. Torque Converter Failure
Torque converter failure is the second most common W8 engine problem, but seems to only occur in automatic transmissions. A torque converter, often referred to as “TC” is essentially what makes the vehicle move. It transmits the engine’s torque to a rotating driven load.
There are many reasons why a TC can fail: slippage which causes overheating, TC permanently locking, or blade deformation or fragmentation. When a TC happens to fail, a CEL or MIL will pop up with a fault code P0740 or P0741. Effects also seen can be engine shudders or slippage. Just like the cam adjusters, the W8 engine is bound to have at least one TC go out during its lifecycle.
Symptoms of Torque Converter Failure:
- CEL or MIL illuminating with fault codes P0740 or P0741
- Transmission overheating
- Metal scraping noise coming from the transmission
- Transmission leaking fluid
- Transmission slipping gears or not shifting at all
Torque Converter Replacement Options:
When a TC happens to fail, the only thing you can do is to replace it with an OEM unit or aftermarket unit. Given the availability of W8 torque converters, the part isn’t cheap and due to the complexity of replacing it, this is a costly repair that is hard to describe the cost. If you happen to know your way around the W8 engine, it’ll probably save you over $1,000 in labor costs.
Torque Converter: Purchase Here
DIY Difficulty: Difficult
3. Faulty Fuel Gauge Sender
Another common problem when it comes to these engines is faulty fuel gauge senders, often referred to as a fuel sending unit. A fuel sender doesn’t send fuel to the engine like its name hints. It actually sends an electrical signal from the fuel sensor to the fuel gauge. Most senders are made up of three main components: a float, metal rod, and a variable resistor.
There are a couple of reasons the fuel sending unit goes bad: premature wear and tear or too much deposit on the variable resistor of the unit. When it does fail, you will notice that the fuel gauge will be stuck on empty or full, which if ignored could leave you stranded on the road. Typically, a fuel sending unit should last the lifecycle of a vehicle, but some are faulty on these engines.
Symptoms of Faulty Fuel Gauge Sender:
- Fuel gauge stuck on empty
- Fuel gauge stuck on full
- Erratic fuel gauge readings
Fuel Gauge Senders Replacement Options:
If the fuel gauge senders happen to go bad, the only thing to do is to replace it. It is difficult finding the location of the unit, however, it is an intermediate repair once located. Given the rareness of these engines, we’ve only seen one instance of a customer paying $1,000 for this type of repair.
DIY Difficulty: Intermediate
4. Excessive Oil Consumption
This is a common problem in many Volkswagen Group engines, including the VW W8 engine. As it sounds, excessive oil consumption is when the engine is consuming more oil than the optimal conditions. Honestly, if you happen to notice the low oil level indicator illuminating in between oil changes, there is a good chance you will want to get your engine checked out. On the VW W8 engine specifically, the 2002’s happen to experience this more often. To mention, in case a mechanic or dealer claims this is normal, excessive oil consumption is certainly not normal.
Symptoms of Excessive Oil Consumption:
- Low oil indicator illuminating
- Engine losing oil at a quicker than normal pace
- Decreased fuel efficiency
- Increased carbon buildup
- Oil deposits in or on the engine
- Blue smoke emitting from the exhaust
5. Catalytic Converter Failure
Lastly, probably the more complex problem to diagnose is catalytic converter failure. The reason we say this is because before suspecting a rough performing engine is caused by a failing catalytic converter, there are many other things that could be causing this. We’ll go more into that below. A catalytic converter essentially filters engine exhaust produced by the engine into less harmful byproducts.
It fails for a few reasons: overheating, clogged, more mileage and age. When it does fail, you will be able to tell simply by a CEL or MIL and the stench your vehicle is emitting. A catalytic converter should last the entire lifecycle of a vehicle.
Symptoms of Catalytic Converter Failure:
- Sluggish engine performance
- CEL or MIL illuminating with fault code P0420
- Black exhaust smoke
- Poor fuel economy
- Engine stalls or difficulty starting the engine
- Failed emissions test
Catalytic Converter Replacement Options:
Given that there is a catalytic converter per cylinder bank, there are four catalytic converters. It may be hard to diagnose which cat is failing, so we suggest taking it to a mechanic. It is worth mentioning, check the MAF and O2 sensors before suspecting it to be a catalytic converter failure. Replacing a catalytic converter will cost around $1000 – $2000 depending on if you choose to go with an aftermarket cat or a factory cat.
DIY Difficulty: Intermediate
VW W8 Engine Reliability
Reliability with the VW W8 engines is not a problem, however, these engines are extremely complex causing repairs to be a lot more expensive. The reason being is that it takes a special mechanic to know how to work on the W8. With that said, we have seen a few W8 engines die from excessive oil consumption early on, but we have also seen some last up to 200,000 miles. If possible, we advise getting a manual since the automatic gearbox tends to go out around 70,000 miles and we advise going with a 2004 version if possible. Let us know your experience with one of Volkswagen’s most complex engines in the comments below!
Also, if you are interested in reading more Volkswagen V8 content, here is an article on “The 5 Most Common Audi 4.2 V8 Engine Problems”.