Well a tapping noise really depends on where at in the engine that it is located. Ie. On the top of the eng this would be a lifter noise. On the sides of the engine this could be a wrist pin or piston prob.
On the bottom of the engine this could be a crankshaft or rod bearing or main bearing
However with the miles on your engine it could be major. I would change the oil and add one qt of trans fluid to the oil. The oil changers will tell you not to do this but trust me it is the only chance of not doing major repairs.
Tuesday, September 14th, 2010 AT 7:45 PM