What determines whether you should buy a 4-cylinder engine or a 6-cylinder?
We are considering the purchase of a Volkswagen Passat station wagon. Our question is whether the six-cylinder engine would last longer than the four-cylinder engine if driven under the same conditions. We live in hilly Seattle. What determines whether you should buy a four or a six? -- Geir
RAY: Good question, Geir. If all things were absolutely equal -- you had the same exact engine with two fewer cylinders -- then the answer to your first question would be yes, a six-cylinder engine would work less hard than a four-cylinder to move the same car over the same terrain. And since it would work less hard, it would presumably last longer. But that's not the only consideration.
TOM: When deciding between two engines for a given car, the first thing you want to determine is which engine is best matched to the car. Like Goldilocks would have said if she were writing for Road & Track magazine instead of Porridge Weekly, "Not too much power, not too little power, just right."
RAY: If you have too big an engine, you'll use excess gasoline, you'll pay more for certain repair costs (more pieces to break), and you'll have to learn to feather the pedal so you don't give your passengers whiplash. For instance, we found that the 2.8 liter six-cylinder engine option for the smaller, lighter VW Jetta was way overpowered for that car. It not only felt unnecessary, but made the car unpleasant to drive.
TOM: On the other hand, if you have too little power, you'll make the engine run hot all the time and that will shorten its life. Not to mention you'll have to suffer the embarrassment of having the guys hanging off the backs of garbage trucks, reading magazines and waving to you as they pass you going up hills. An example? The four-cylinder base engine they used to offer for the Ford Taurus (which they've since eliminated due to massive customer humiliation).
RAY: In our opinion, both of the available engines are within the adequate range for this Passat. So then you go onto other factors, like the specifics of the engines. The six-cylinder is really shoe-horned into the engine compartment of this car, making it hard to reach stuff. So you'll probably spend more on labor to fix it. On the other hand, the 1.8 liter four-cylinder engine has a turbocharger, which costs half as much as the engine to replace. So here again, you've got a wash.
TOM: So in your case, I'd base my decision on the type of driving you do. And since you live in hilly Seattle and you presumably plan to carry "stuff" (hence, the station wagon), I think I'd opt for the six in your case. Of course, we could have just told you that in the very first paragraph, Geir. But remember, we get paid by the word.