How to Tie into the Cooling System on a Mercedes Benz to Install a Waste Vegetable Oil System

This article will show you where to tap into the cooling system to heat your waste vegetable oil fuel lines without draining the coolant.

If you are going to use a flat plate heat exchanger and heated fuel lines you will need to tie into the factory cooling system. You need a supply and return line. The supply line is on the driver's side of the engine near the oil filter. I like to use needle nose locking pliers or clamps to contain the coolant. You have to use one on each side of where the cut will be. Once the cut is made you can install the tee. It must be rated for the temperate. Napa has the correct parts. Don't use the cheap plastic ones, they will melt. You can use brass or steel threaded parts from the home store to make your own tee's. The brass tee's made for pex lines work well. If you want to splurge you can install a valve at each tee to shut off the coolant if you need to service the wvo system.

Most MB's are equiped with an electric coolant pump mounted on the passenger's fender near the front of the engine. The pump is used to push heat to the cabin while the engine is at an idle. Most guys like to cut the return into hose between the pump and the motor. I like to cut in right before the pump and wire it to come on with the ignition. That way it can be used to help the coolant move through the wvo system.

It can be difficult to purge all of the air out of the heated line. I use a garden hose to force water through the wvo system right before I attach the lines to the tee's. Once everything is connected you can run the engine and check for leaks. Feel the lines and heat exchanger for cold spots. A cold spot means you have an air bubble trapped in the line. I should work it's way out as you drive, but it may need to be forced out with the garden hose. The information in this article can be applied to other vehicles.