I have a 98 Camry with a 2.2L 4 cyl engine. There is a metallic rapping noise (only way I can describe it) that sounds like it is coming from under the valve cover. It varies with the RPM of the engine, but also fades as the RPM goes over 3000. I have taken off the valve cover, and it looks like the exhaust camshaft has been replaced (not as varnish coated as intake camshaft). I checked the bucket shim clearances and adjusted a few that were out of spec (with new shims). The rapping is still there. I am stuck as to what else could be causing the noise.
Might be piston or bearing noise. Unplug one sparkplug wire at a time if the noise goes away for that cylinder then it's either a bearing or piston noise.
August, 20, 2013 AT 12:39 PM
I have tried that test already and it made no difference (this test was suggested by a mechanic as a way to check for connecting rod bearing issue). I have also replaced the spark plugs with new ones as well.
It was suggested by others that it COULD be the water pump, however the noise sounds like it is under valve cover, not by water pump area.
August, 20, 2013 AT 12:43 PM
Ok well then take a long screwdriver and puton various places on valve cover to try to see where noise is. Then remove fan belt an dstart car is noise goes away it is in the belt drive area of car.