Five problems related to timing tensioner have been reported for the 1998 Ford Explorer. The most recently reported issues are listed below.
The timing chain tensioner broke allowing the chain to slip. It was a recall problem but I was not the original owner and the problem must not have been addressed, or else the recall didn't get done properly. After the repair it hasn't had good oil pressure at idle. It is too bad that Ford put this motor in so many vehicles and doesn't stand behind they. It is poor design in my opinion to have four timing chains on a 4. 0 liter motor is crazy. I wish that Ford would have put more effort into seeing that my vehicle were recalled and not allowed to depreciate because it was happening to so many other Explorer.
Very heavy rattling in the engine of my 1998 Explorer 4. 0 sohc. Took to local Ford dealer, they claimed characteristics of the motor, twice. Some time later tensioners broke while driving and motor ceased. No cooperation offered on Ford's part. Had to replace engine out of pocket for Ford's design flaw, which has been getting swept under the rug for years now. One month after the replacement Ford offered to fix others, if found before 75k miles, etc. Too late for me. How many failures have occurred? what if this failure had of occurred at highway speed, instead of idle speed. Check the figures on this problem, it's scary, and Ford is pitiful.
Rear chain guide tensioner broke - part of cam chain guide assembly. Engine died in morning rush hour, but car coasted safely to emergency lane.
Vehicle experiencing engine noise, cam tensioners were installed to correct problem, vehicle is still noisy.
Ford is offering to replace engine components, but damage has already occurred to the motor. The motors should be replaced also. Failure to have a recall for the camshaft tensioners can result in an engine seize resulting in a crash if at highway speeds (for example).