79-85 Mercedes

Mercedes Conversion

One of the easiest and best cars to convert is a classic late 70s/early 80s Mercedes Diesel. Costing over $40,000 new back in the 80s, these cars were "overbuilt" having numerious backup systems for when the main parts fail. They are also tolerant of the rigors of running vegetable oil due to their robust lift and injection pumps and well built engines. People have successfully run SVO in these cars with no modifications. More common and dependable are dual tank systems that come in a variety of configurations. Many of these cars suffer from abuse and neglect, yet keep on running. To fully restore such a relic would cost a fortune, but catching up on basic maintenance is not so challenging. Many of the maintenance items are easy enough for the novice, especially witht he helpful books and videos out there.  Pre-conversion maintenance items:

*New Thermostat

*New air filter

*Fuel filter

*Valve Adjustment

Also, it would be wise to perform a compresson test to gauge engine health before forging ahead with a conversion. An unhealthy engine is not going to like WVO.

Key Integration:

-Fuel:   Mercedes stock fuel line is in between 3/8 and 5/16.   It is best to use 5/16" fuel line for integrating into the stock fuel fittings.   Cut the stock "clear" fuel line at the barb, leaving a section on the barb.  The 5/16" line fits perfectly over the barb with the old stock hose, and will make a nice connection with a hose clamp.   

-Coolant:  Splice into the coolant lines in two key spots.  One is behind the oil filter, the other is near the outlet of the water pump.  3/4" barbed Coolant T's work well for this.  See pics below.

-Electrical: Source keyed power from the fuse box, on the fuse prong of a circuit which has keyed power, like power windows.   

Conversion Schematic

Complete Parts List:

Tools Needed

• Wire Cutters and Crimpers


• Screwdrivers


• Cordless Drill


• Hole Saw bit


• Patience

Conversion Pics

Additional Resources

Mercedes Forum http://www.peachparts.com/shopforum/index.php

DIY Articles, parts http://www.dieselgiant.com

Parts http://www.mercedessource.com http://www.autohausaz.com