I’m a big fan of German cars, as I noted in my introduction. My first loves are all generations of the Smart Fortwo. But recently I’ve been drooling over Ferdinand Piëch-era Volkswagens. I’m not sure what it is about them that draws me in. They’re cheap, some of them are fast even for today, their styling isn’t overdone and a few examples are just downright bonkers. That said, Volkswagens from this era do have a reputation for being quite unreliable.
Even so, I continue to buy Volkswagens and Audis in various states of disrepair. My current fleet includes an Audi TT Quattro Mk1, a Passat W8 with a six-speed manual, a 354,000-mile Jetta Sportwagen TDI and a Passat TDI wagon.
What started this new direction in car-collecting for me was a Passat TDI wagon similar to the one I own now. It was my first diesel and uncharted territory for me. I’m used to owning a sizable fleet of Smart Fortwos and I know how to work on them, but the Passat was something different. As such, I was a bit intimidated by taking on such a huge project outside of the scope of my knowledge.
Some Cars Come With A Learning Curve
While I’m a living encyclopedia about the Smart Fortwo, that knowledge didn’t translate to Volkswagens as well as I expected. Still, I love to learn. On this particular TDI, the previous owner claimed that the car had a mystery fuel delivery issue. His dealership apparently believed so, too, as they replaced the turbo, N75 valve (electronic solenoid that helps control boost pressure) and vacuum lines, but still couldn’t get the car to accelerate as it should.
Through wonderful people in online Volkswagen communities and a couple of Jalopnik readers, I learned a ton about keeping these TDIs alive. One of the tools they told me to get is a VCDS diagnostic tool. Why guess what’s wrong when this bad boy can show you what the car is thinking and doing?
Thanks to the tool I learned the car’s fuel delivery was fine, it just wasn’t getting any turbo boost. I couldn’t figure it out until oil began spraying all over the engine bay. I believe what occurred was that the charge pipe going to the intercooler was damaged, but in a visual inspection it appeared OK, leading the mechanics to replace other parts. Below is that oil-soaked charge pipe. To the naked eye it looked fine.
At any rate, under pressure the pipe revealed a gash, as if Wolverine (the Marvel character) had swiped at it. Sadly, while I knew what to do to fix the car, and the part was free, I wasn’t feeling so well at the time and the motivation just wasn’t there. I decided let the car go for a Mercedes-Benz 240D. The Passat’s new owner confirmed my theory, and a new charge pipe brought the car back to 100 percent.
The Audi TT and the Volkswagen Jetta TDI Sportwagen I bought over the summer both needed minimal work. The Jetta needed tires; the Audi a starter that took 10 minutes to replace. Neither was a challenge, and both remain reliable vehicles in the fleet. But I still had an itch to fix a broken diesel wagon, perhaps as redemption for giving up on the first.
A Second Shot At Fixing A Diesel Wagon
Now with some troubleshooting knowledge gained, I decided to tackle another Passat wagon. I had fun troubleshooting that last one even if I didn’t fix it. When the new owner told me that my diagnosis was right on the money, it made my day. So I made it a mission to find another diabolically cheap Passat TDI wagon to repair.
That happened when I brought this example home in August for $1,000.
The seller told me the car “needs a new EGR system” because it was making a bad noise. I hopped in, took it for a drive and looked everything over. I had determined the EGR not to be an issue, but instead that the problem under boost was most likely caused by a vacuum leak. Because the brake pedal was firm, I was thinking that the problem was a crack in the vacuum line coming from the vacuum pump driven by the engine, a common failure. The pump itself could also fail.
And the sound? Ah, it’s probably just a bad motor mount. I figured I would fix the mounts after solving the boost problem, so I got to work tracing vacuum leaks. But before I could even find them, the car threw me another curveball.
I Think It’s Dead
During a drive home the “motor mount” noise seemed a bit louder, but the car still drove fine so I shrugged it off and kept going. Then, roughly 10 miles from home, the unthinkable happened: A big red STOP text appeared in the gauge cluster, accompanied with a flashing oil pressure light. No way, it was driving fine, so it definitely had to be a sensor, right…RIGHT?
I was afraid of the worst so I sort of let the car sit without touching it for a while. Eventually I decided to hook up an engine oil pressure tester; the engine didn’t even move the needle. In fact, the engine didn’t even wet the tube with oil. I checked the tester with another car just to be sure. Bad news: It was not just a sensor. The engine makes no oil pressure at all, even when revving. That noise? I’m thinking it’s actually the balance shaft module.
The Engine’s Weak Point
The 2.0-liter BHW diesel engines in these Passats are fairly robust. However, one critical part is known for its failures: the balance shaft module. This component is responsible for cancelling out engine vibration, but it also drives the oil pump. A common point of failure is the hex-shaped shaft that drives the pump. The gear that drives the balance shaft can also wear out. The end result is likely zero oil pressure.
Replacing the balance shaft module is a big job, far bigger than I can handle or even want to handle in the approaching low temperatures.
The good news is that once this issue is fixed the engine should be, some would say, bulletproof.
Unfortunately, I will not be repairing this one. While this car has a decent body, it has 292,000 miles and a rough-ish interior. For the cost of fixing this I would rather buy a better and lower mileage example of the same car.
So, instead I will be farming parts out of it for my Passat W8 restoration project, then sending it to a new home. Maybe it’ll be put back on the road again, but I am somewhat doubtful. I do hope what good parts it has will be used.
I’ve managed to strike out twice on Passat TDI wagons, maybe a third time will be the charm!