The VW TDI Diesel Engine for Fuel Economy MPG
You may be considering an expensive hybrid car of some configuration and did not know that VW has had one for sometime, the TDI diesel engine. This diesel is special to Volkswagon for well over 10 years and VW has continually fine tuned it to the point that in 2009, they created the "clean, low emissions" diesel.
The VW diesel engine whips the current the crop of Japanese hybrids in many ways, most notably, in performance and MPG. These German cars, Golf, Jetta, Passat, with a TDI engine (turbo direct injected) easily have 30\45 MPG. Good then, now and well into the future. It use to be cheaper to buy diesel, but nowadays, diesel runs .40-50 cents more a gallon, but the trade off in MPG is well worth it-over 600 miles on a tank of gas ($45)! Even pre-2005 models get similar MPG. So, you do not need to buy a new one.
Finding diesel is a non-issue, all gas stations also have it. The VW TDI is more expensive new and used, they do retain value for years. They are more expensive to maintain and repair and finding a good diesel mechanic could be an issue.
The diesel engine has always been one of longevity when maintained. Cars with even 160,000 miles or more, when maintained, suffer from few issues. If the car was not correctly maintained, like gas engines, will have issues. The diesel engine is simpler than a gas engine. The engine has no spark plugs, coil, distributor, or spark plug wires. They could care less about air-fuel ratio mixtures. It has no oxygen sensor.
The most critical maintenance item is the timing belt that must be changed at 80-90K miles. If the belt breaks while driving, your engine will suffer serious damage. The TDI engine also must have special oil, which is not hard to find, but you cannot just use the usual stuff. If the wrong type of oil is used for many miles, your engine will suffer Cam and Lifter wear. This is a costly repair. Worn Cams will cause the engine to idle unsteady, excessive smoke or noise. This is the TDI's weak link. The Turbo itself suffers little. But a turbo not working properly will cause excessive smoke and the car will have serious acceleration issues. Changing the oil and fuel filters are not much different than on gas cars. Use oil rated CG-4 or CH-4, synthetic like: Mobil Delvac 1, Chevron Delo 400, Shell Rotella T, all 5w40 with 505.00 or higher rating.
Buying a used TDI VW is like any car, but if you do not know the maintenance, just presume it was not done regardless of the miles. The timing belt and correct oil use is most important. The mileage of the car, unlike with gas engines, is less important except for the fact other parts may wear out faster than the engine. Even a diesel should not have excessive smoke when idling at 2500 rpm, if it does, think worn rings. If the engine is loud and unsteady at idle, think worn Cam from wrong oil being used. Try to inspect the timing belt. There will be the smell and some light black smoke, that is a diesel.