Uh oh: VW TDIs Might not be just rosy MPG numbers.

By Zack Klapman

Remember that 2012 Passat TDI that I loved so very much? The one that went about 800 miles on a single tank of diesel, quietly, saving my body from the coarse hands of TSA agents? Right. Well, turns out that as quiet and miserly as modern diesel engines are, they aren’t matching up to the staunch reliability of the dependable past generations.

The Passat TDI is running into reliability problems, most notably, the high pressure fuel pump. Several links were emailed to me, taking me to various forums with people telling their tale of vehicles stranded on highways, and long repair times.

What I gather from the stories (300 pages on TDIclub alone) and the NHTSA investigation from last year (pasted below), is people are having a complete drop in power under acceleration. Sometimes their Glow Plug warning light comes on. Many were able to turn the car off and on, temporarily fixing the issue. Others were forced to call a tow truck. It seems that the Bosch-made High Pressure Fuel Pump has been failing due to fuel contamination (either gasoline entering the diesel tank at a gas station, or poor quality diesel). So far the problem has been reported in 0.53% of MY 2009 vehicles and 0.11% for MY 2010 vehicles. It’s not millions, but it’s enough to have some of the forum members advising “DO NOT BUY A 2012 PASSAT TDI.” Strong words, but if my new car had been in the shop for 3 weeks, I’d be pissed too.

From the NHTSA Investigation:

Summary:
The Office of Defects Investigation (ODI) and Volkswagen (VW) have received a total of 160 complaints and field reports alleging incidents of engine stall and/or loss of power that appear to be related to high pressure fuel pump (HPFP) failures in certain model year (MY) 2009 through 2010 Volkswagen Jetta and MY 2010 Volkswagen Golf and Audi A3 vehicles equipped with TDI clean diesel engines. Approximately half of the reports indicate that the failure resulted in an engine stall incident, with many of these alleging stall incidents at highway speeds in traffic with no restart. There has been one minor crash alleged to have resulted from HPFP failure in the subject vehicles. In response to ODI’s information request for PE10-034, VW indicated that it had “found no defect related to motor vehicle safety with relation to the TDI Clean Diesel fuel system at issue in this investigation” and attributed problems with HPFP failure to operation with gasoline contaminated diesel fuel. Volkswagen stated that “even a small amount of gasoline in the diesel fuel may disrupt the necessary lubrication required and may cause the HPFP to fail.” In response to concerns that fuel contamination was the major cause of HPFP and related fuel system failures, VW issued a Technical Service Bulletin in May 2010 (VW TB V011011 2023624 and Audi TB A011008 2023360-1), with instructions to inspect the diesel fuel for vehicles requiring fuel system service that have symptoms associated with HPFP failure. The bulletin states that “fuel system damage incurred by use of fuel not complying to ASTM-D-975 Grade 2 S15 (B5 or less biodiesel content) standards will not be covered under warranty.” Volkswagen also provided information about 121 mis-fueling incidents reportedly acknowledged by consumers or dealers and test results for about 50 diesel fuel samples taken from complaint vehicles in late-August through early-October 2010. The mis-fueling incidents include about 20 reports involving incorrect fueling by dealer sales or service personnel and generally report symptoms such as rough running, stalling and/or no start within a few miles of refueling the vehicle with gasoline. Volkswagen indicated that the testing of fuel samples from complaint vehicles found that nearly 90 percent contained high amounts of gasoline. Volkswagen implemented design changes for the HPFP in May 2008, September 2009 and November 2010 to improve the robustness of the pump when used with poor quality fuel. ODI analysis of HPFP failures identified from all sources shows failure rates of 0.53% for MY 2009 vehicles and 0.11% for MY 2010 vehicles. This investigation has been upgraded to an Engineering Analysis to continue to investigate the issues with mis-fueling and HPFP design identified during the Preliminary Evaluation.

So what’s basically happening is, people are filling up their cars with diesel, but somewhere between the dinosaurs dying and the fuel going into their cars, it’s being contaminated with gasoline. Sometime the fuel delivery trucks put the pipe in the wrong hole (“accident”, sure it is buddy), or truckers taking shortcuts when they’re transferring to the tanks, but mostly it’s that diesel fuel in America is of a lower quality than in Europe. The oil content of diesel actually lubricates the fuel pump, but when it’s contaminated with gas, that lubrication is reduced, causing the failure.

The real problem is VW‘s statement, ‘“fuel system damage incurred by use of fuel not complying to ASTM-D-975 Grade 2 S15 (B5 or less biodiesel content) standards will not be covered under warranty.” ‘

As if I or you can verify the quality of our diesel. If that’s their beef, fine, but take it out on the refineries, or the gas stations themselves, not on the people that were nice enough to buy your cars, and simply tried to continue driving it.

If you still want to buy a TDI, either get one from pre-2009 (not known for this problem), or make sure your dealership signs a bunch of papers saying they will replace your entire fuel system if/when it bites the dust.

Hopefully, this will result in Bosch (the fuel pump manufacturer) addressing the issues of our domestic fuel, or the fuel companies doing it themselves. Diesel engines are gaining popularity in America, and we can’t have them failing due to sub-par fuel. Knowing our citizens, that will kill the new-found popularity quite quickly.

Source: MyTurboDiesel.com, NHTSA

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