What Car? Q&A - Should I buy a diesel C-Class?

Q: I’m interested in the Mercedes C-Class and agree with What Car? that the C180 seems good value for money. I’ve also been looking at the C320 CDI diesel, which is £7500 more. Can an engine upgrade be worth this much?
David Cadman

A: The difference between a C180 and a C320 CDI is more than one step up in engine output. A C200 CDI is a more comparable diesel with the C180 and doesn’t come with a price premium anywhere near as big.

It would be all but impossible for you to recover the C320 CDI’s premium in the marginal 2.8mpg fuel saving it brings, even over many decades of driving.

In fact, if you’re considering these two particular models, you’d need to cover 2,114,430 miles in the C320 CDI to claw back the extra cost. This compares with a still significant, but more realistic, 76,000 miles in the C200 CDI.

While none of this considers the stronger resale values of the diesel, or other running costs such as servicing or insurance, it illustrates the point.

If you are having to drive the equivalent of to the moon and back five times, the 320 CDI will not justify itself in lower fuel costs.

However, it could be worth the extra money if the faster acceleration of the C320 CDI is important to you. After all, added speed is obviously enough to convince some buyers to go for the C55 AMG, and that’s another £17,000 more.