Model: Mark 3 GTI , 8v, Golf, ADY engine. Problem: Coolant Temp gauge not working. Fires first time of asking in cold. When warm, not so. On the black plastic flange on the cylinder head, one of the holes is blocked off. The second contains a four pin black (yellow stripe)sensor. Am I right in saying this sensor also sends info to the ECU? In other words, could my starting problems (from warm) be connected to this sensor being shot? Thanks in anticipation. John
