Let's put some numbers on the timing belt issue, which I feel is a little blown out of proportion (at least for the manual trannys).
Don't forget a gasser needs a new belt from time to time as well. Change interval for TDI manual: 90k kms. Gas engine: 160k kms.
In Canada, let's be generous and assume the stealership charges $500 for the belt (it's less than that I believe, but just to be safe...). Figure it out. Timing belt cost for the gasser is 3/10 cents per km. On the TDI, it works out to just a little over 5/10 cents per km (5.55 to be exact).
For someone like me who averages 30k km/year, my annual "timing belt allowance", as it were, is $167. For a gasser, $90 per year.
Now the fuel savings. This week I had a 2.0 gas. Got my usual 8.5 l/100 km with the 2.0. TDI gets, under the same driving mix, about 5.5 l/100 km (annual average, about 5.0 in summer, 6 in winter). At 80 cents/liter that's about $1320 of diesel fuel, vs. $2040 of gasoline for the 2.0L.
Annual savings: $720, or 2.4 cents/km. Timing belt difference is mimimal in comparison, $.0025/km, so that the actual savings for the TDI is 2.1 cents/km when you factor in the more frequent belt changes.
Yes, a timing belt is a pain in the butt to change, yes, it eats into cash flow for the year you change it in. But relative to the other savings, it is barely noticeable. On top of that, I haven't even factored in the lack of need for spark plug changes, and other maintenance issues peculiar to cars that consume the explosive stuff...
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PlaneCrazy
99.5 Jetta TDI GLS
76 Piper Cherokee