Ford Explorer Forum : “2003 explorer 4.6 whining noise at front of engine,timing tensioner or belt tens...”

Hi convertable ... Could be a number of things, precious few of them good. What I am worried about however is the timing belt. If you haven't swapped yours out yet at 98K miles then you should run not walk to your nearest mechanic and get this noise checked out. You should also know that this model has a history of issues with the timing tensioner too although at this point is may be a "chicken or the egg" argument in your explorer. Get it looked at ASAP.
Good luck!

There was a recall on the tensioner for several models, so you might be in luck to have this covered by the Ford warranty. My 2001 Explorer Sport had a whining noise and the check engine light would come on at the most inopportune times. Turned out to be the timing tensioner and belt issue. Like LouB says, RUN don't walk and see if this can be warranteed for you.

Could be the timing chain guides.Ford had problems with these.

i have a 97 ford and mine whines like theres no tomarrow it turns out to be the guides the chains slides over, typical FORD

a tip to find ou twhats goin on is to take ur serp belt off and start your truck and if the noise goes away its not the timing chain its an accessorie run off the belt, tensioner pulley or water pump bearing, anything run from the serp belt