Every watercooled VW needs an oil cooler. Volkswagens simply run with too high an oil temperature in stock form. A high-output engine in a cramped engine compartment can generate a lot of heat, even without a supercharger. Not only do high engine temperatures contribute to lubricant breakdown, they also contribute to shorter engine component life.A properly installed oil cooler will give your car extra thermal reserve to keep heat under control during periods of peak demand. Oil lubricates best in the range of 180 to 212 degrees F (82 to 100 degrees C). Below this range, the oil isn't hot enough to burn off volatile contaminants, and above 230 F (110 degrees C), it starts to thin out and oxidize. Our sandwich plates return oil to the engine when it's below 180 degrees, allowing the engine to warm up quickly. Once warm, the thermostat opens, and the oil flows to the cooler to keep temperatures within the ideal range. Mocal Thermostatic Sandwich Plates provide a convenient means of getting engine oil to and from the oil cooler. They mount between the oil filter and the oil filter mount, hence the name. Our sandwich plates are supplied with special aircraft fittings to make leakproof connections a snap. Autotech's Sandwich Plate is compact, very important in the often cramped VW engine compartment. Fittings attached are -10AN male. Comes complete with o-rings. VR6 cars also use a sandwich plate, but it mounts directly to the engine block, rather than on the filter flange. Includes a special cover plate and 2 filter studs (1 for use with stock oil cooler 1 for bypassing stock oil cooler).