VW Jetta Diesel Problems

One problem with some Jetta TDIs is difficulty in starting the engine, or an engine that won't start at all. This can happen for several reasons, but in many cases it is related to the glow plugs, which diesel engines use to produce ignition instead of spark plugs. A lack of electricity to the engine due to faulty wiring or a discharged battery may be to blame.

A known issue with the Jetta TDI involves improperly assembled driveshafts. This problem, which stemmed from Volkswagen's failure to properly install screws on a driveshaft cover plate, was the subject of a recall for more than 25,000 vehicles in 2009. In the worst cases, the driveshaft cover could detach and leak oil onto the road.

The Jetta TDI has also suffered from problems with its automatic transmission. This was the cause of another 2009 recall that involved some 16,000 Volkswagens. The recall was enacted to correct faulty wiring in the Jetta's direct shift gearbox, which could cause the transmission to shift into neutral without warning, putting the driver in danger of crashing.

A common Jetta problem involves smoke coming from the exhaust system, either during hard acceleration or, sometimes, normal driving. Smoke is usually the result of the engine burning oil, which happens during the normal break-in period for a diesel engine. However, smoke coming from an older engine can indicate several problems including improper timing of the fuel-injection system, clogged injectors, a clogged air filter or poor quality or contaminated fuel.

One series of problems with the Jetta TDI are simply related to its use of diesel fuel and may not indicate faulty components. Burning a small amount of oil is normal for diesel engines, but some drivers find this troubling or complain about the need to occasionally add engine oil. Car critics from The Truth About Cars website have noted that the Jetta TDI lacks the responsive performance of its gasoline-powered counterparts.