Posted: Feb 13 2010 at 6:36am | IP Logged

If the clicking noise is as you described, it could be A) Something external to the block like something you jarred loose on a rotating item that is hitting something or a bad belt tensioner or; B)something internal to the engine like a valve trian component or and injector that decided to act up.  SInce it did not do it before A is more likely than B.  When the belt is off , I assume that the water pump, alternator and fan as well as the air conditioning compressor (if you have one) were NOT turning.  If this is the case, then the main drive pulley on the crank must be the culprit.  See if this is loose or if there is something on this pulley that is sticking out and hitting something.  Run the engine without the belt (when cold) with the hood up and listen.  Carfully use a mechanics stethescope if you have one to see if it helps locate the noise.  It will quickly tell you if the noise is internal to the engine, for example.

Also, does the ticking correspond with the engine RPM on a 1:1 basis or is it slower?  If it is 1 noise to 2 engine revs, it would indicate a valve train noise.