A rattling noise from the engine may indicate that the timing chain cassette is worn. Our technicians tell us that installing an updated cassette and timing chain tensioner should correct this concern.Google+
Car Problem Reports
Ford Explorer Worn Timing Chain Cassettes May Cause Rattling Noise From Engine
Ford Explorer Problem
Engines Affected: 4.0L V6, 4.0L V6 SOHC, 4.6L V8
Average Mileage: 127,814 mi (42,000 mi - 180,000 mi)
A year ago I had the upper and lower intake, the plenum and head gaskets replaced. There was a slight rattle and was told it was a heat shield on my exhaust close to the manifold that had a broken weld and was rattling,I already knew this to be true I had found it doing an oil change. The mechanic removed the heat shield hence removing the rattle only there is one huge problem the rattle didn't go away but got worse. It is so loud now that my V6 sounds like a diesel while idling and even worse when accelerating, HELP!
Visitor, 2004 Ford Explorer, 4.0L V6 SOHC, 141,000 mi
Noisy timing chain tension adjusters and has not been repaired yet. Looking for economical solution.
Visitor, 2004 Ford Explorer, 4.0L V6 SOHC, 121,000 mi
Rattle noise at cold start is becoming more apparent most of the time.
Visitor, 2003 Ford Explorer, 4.0L V6 SOHC, 160,000 mi
all 3 timing chain cassettes broke causing all 3 camshafts to jump time.it bent 5 valves I had to have engine removed for repair( r. side timing chain cassette can only be accessed from inside bellhousing flange!)also had to have auxilliary shaft brgs. replaced because the front 1 had spun into the engine resulting in sudden loss of oil pressure.my mechanic said "this engine must have been designed by aliens!" it is actually designed by, Ford of Germany. there goes my faith in Ford delivering a well designed &built product!
Visitor, 2000 Ford Explorer, 4.0L V6 SOHC, 110,000 mi
Rear timing chain cassette was broken causing rattling noise, engine had to be removed in order to repair it.
Visitor, 2002 Ford Explorer, 4.0L V6, 146,000 mi
valves rattlin like it lost its oil preasure
Visitor, 1997 Ford Explorer
Small rattling noise turned into timing chain broke cover and lost all oil out of top of motor
started hearing a rattling noise one day.the rear timing chain snapped and came through the valve cover.apparently this is a common problem with these motors.a friend of mine had this happen to both of his 04 explorers,and its the biggest problem i find on every forum. .it was pretty easy to diagnose the problem since about 5 inches of chain was sticking out of the cover and oil was everywhere.i currently have the motor out of the car (which you have to do to replace the rear timing chain).
Visitor, 2000 Ford Explorer, 4.0L V6, 93,000 mi
Ford XLT Explorer. My mechanic removed the oil filler cap to listen to the sound coming from the right side front of the motor. It sounded like the clicking of a diesel near where my power steering pump is located. This problem seems to be intermittent. It was not there on a cold start so I left and drove a short way; parked for about 15 minutes. Upon restart, there it was. It's his opinion that a timing chain nylon tensioner on the front is either worn or gone entirely causing the chain to slap the sides or the another chain that is near it. It takes special tools for this so he recommended I take it to Mountain View Ford in Chattanooga to diagnose and repair. Carl
Visitor, 2004 Ford Explorer, 4.0L V6, 101,000 mi
Rattle coming from engine almost sounds like a bad valve.