How to Improve the MPG of the Mercedes W114

1. Tune up the engine. The Mercedes W114 was manufactured in the days before computers, so any competent backyard mechanic will be able to do a basic tuneup of filter and spark plug changes. A more complex tuneup, like changing points, a condenser and a timing check, can be done by a qualified mechanic.
2. Change the oil and add a new filter. New oil reduces friction on engine parts, and less friction in any engine equates to better fuel economy.
3. Remove any excess weight. The lighter your W114 is, the less fuel it will take to make it go. Tools, salt and sandbags -- even sporting goods equipment like golf bags and camping supplies -- all add extra weight.
4. Inflate all the tires to the manufacturer's recommended tire pressure. All under-inflated tires will cause more friction going down the road, and unnecessary friction causes a reduction in fuel economy.
5. Remove bicycle and ski carriers, luggage racks and any other drag-inducing exterior attachment. Wind resistance from these items lowers fuel economy. In essence, the engine must work harder, and therefore burn more fuel, to compensate for the extra speed-reducing drag on the vehicle.
6. Follow fuel-reduction driving habits. Do not speed, don't idle excessively, use the cruise control if applicable for your particular model, and keep your transmission shifted into the highest gear possible to reduce engine rpms.