What are the symptoms of a timing belt that needs to be be changed on a 22RE? And how hard is it to fix? I was checking out at a nice looking '90 4x4 at a dealership tonight. It was a 22RE with 129,000 miles on it. When I started it up the ingine ideled smoothly, but there was a distinct and very rapid metal pinging sound comming from the engine. I couldn't pinpoint the source of the sound but it almost sounded like a valve clearance issue. Also when I climbed under the truck there was evidence of small oil leak down the front of the engine. It was dark so it was hard to tell, but the leak appeared to be comming from the bottom of the chain cover. Thanks, Curran.