I have a 2006 Mercury Mountaineer AWD with the 4.6. At start-up, when the engine is cold, there is a loud and very noticeable knocking sound coming from the passenger side of the engine. I have ruled out the ever noisy injectors. After about 30 seconds, the noise reduces to an acceptable level. Lately, it is getting worse. I have chased the noise down to the front of the passenger side valve cover/exhaust manifold area. As I said, the noise gets better when the engine warms up. I am using the 5W20 oil recommended and change the oil before the computer tells me to. Any ideas as to what this could be?
have the same problem?
Saturday, June 25th, 2011 AT 10:36 PM