Question about Mercedes-Benz 420-Series
No. The lack of heat is usually attributed to the heater control valve tearing a diaphragm. They also use an electric waterpump on the passenger near the fender well. These items do need to work in conjunction with one another. Let me guess, heat will trickle in until you hit the gas and then nothing?! Typical of the heater control valve behind the firewall, passenger side, under the hood. Black in color and a 2 pin connector to it. It uses a electromagnetic solenoid which when activated, raises the diaphragm and allows water to pass. When torn, they block the flow. What makes these so easy is, when you remove the 4 slotted head (or flathead) screws in the small square control valve, you lift it up and replace the diaphragm. You loose very little coolant and it only takes minutes. You can find the repair kit online for about $15. Let me know if you need anything else.
Posted on Nov 08, 2010
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Posted on Jan 02, 2017
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