I’m replacing a failed turbo on a customer’s 2013 Passsat TDI diesel, the car already has 290,000 miles on it. The customer insisted I replace the DPF since the labor to remove it would already be done in the process of replacing the turbo. So I go ahead and order the parts. Likely thanks to dieselgate and the number of cars being fixed to be resold, there is a shortage of new diesel particulate filters (DPF for short) for these cars. I had to wait for one to arrive from Germany. Ordered it in late July and just showed up on Tuesday (9/17).

Anyway, sometimes I just have to stop to admire inventions that do what once upon a time was thought to be near impossible, such as making diesels not belch black smoke.

Photo #1 is the exit from the turbo and into the oxidation cat and DPF:


Typical sooty exhaust, right? Actually, really doesn’t look bad at all for 290,000 miles of accumulation compared to diesels from 15+ years ago. Testament to how good the super high pressures and ability to have much more control over injection events that modern commonrail technology allows.

But that’s not the impressive part. The impressive part is what comes out of the DPF, or more accurately, what isn’t coming out of it:

Pristinely clean exhaust downpipe with 290,000 miles on the car. I never cease to be amazed at how good these work. They have certainly had their growing pains, but at least in VWs case, as they moved on from the gen 1 engines, the reliability of the DPF seemed to increase drastically.

Now if we could only get all of them to be so reliable, we’d have less guys removing these and rolling coal. Diesel emissions controls today are akin to what gas engines had to go through when emissions laws first were enacted in the 70s and on into the 80s. There were a lot of growing pains and poor performing engines which many people then bypassed to gain back reliability and drivability. Given enough time and resources thrown at it, things turn out very well.


This customer keeps meticulous track of his mileage on Fuelly. His lifetime average is 46.6 MPG so far, which is ridiculous for a car this size. Seriously, the 2012 and up Passats are HUGE. You don’t realize just how huge they are until you compare their length with other large vehicles side by side... or just get into the back seat and realize there’s a surprising amount of leg room back there. Getting a lifetime average MPG in the mid 40s with a vehicle this size is crazy.

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