'98 jeep cherokee clicking noise

i bought a 98 jeep cherokee sport 4.0 liter 18 months ago from a
dealership and have had no major problems with it. i got the front cv
joints replaced and had a bar under the motor replaced that made a
click noise when i turned. recently i have heard this clicking noise
when i accelerate like the fan scraping up against a piece of metal. i
could start up the car and not have a noise but sometimes when i left
it running to long it would start clicking. two days ago i warmed it
up in the morning and when i got in it was clicking, but i left it
idoling so i was taking a chance that it would click and usually after
i turn the engine off for a few hours it will stop. well it has not
stopped. it has gotten ten times worse. now when i turn the car on i
get this obnoxious clicking noise that only gets worse as i acclerate,
it clicks faster as i accelerate. but when i reach 45-50 mph it
completely stops and will not click over 45. then if i bring it down
again it starts doing it again. it clicks with the shifting of the
engine when i hear the engine shift i hear the clicking shift with it.
i have read up a little and have a feeling it could be the timing belt,
but people say something about a timing chain??? i have a belt i think?
well i have tried my best to explain what went wrong with detail and as
percisely as possible, please help...

 

One possibility: Exhaust or intake leak - they tend to come and go with
engine temperature changes, get worse and less temperature dependent as
time goes on (particularly exhaust leaks as the leak burns bigger and
bigger), and are acceleration dependent.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Take a look inside the fan shroud to see if the fan is touching the
radiator - with the engine off, of course. We had a similar issue with
our '95 Cherokee and the motor mount was broken, allowing the engine
position to shift and just barely scrape the radiator. We replaced the
right mount and that corrected it.
Good luck.