Rattling coming from 4.0 SOHC 2000 Sport

[mizestang]

Guys, I need some help. I've got a pretty loud rattle sound coming from my explorer at idle and basically throughout the rpm band. It not a tensioner or anything like a pulley. It almost sounds like rockers ticking, but its more from the front of the engine. ANy ideas on what this could be?

 

[stangman82]

oil levels good i assume?

Timing chain's bad.

 

[2000StreetRod]

crank/jackshaft chain tensioner

Here's a link to a thread about a common problem that develops with the SOHC V6s as they age. TSB 02-7-6 4.0L SOHC Timing Chain Rattle The tensioner for the chain from the crankshaft to the jackshaft wears out. Also, the chain that rotates the driver side camshaft is located in the upper front driver side of the engine.

Try using a mechanic's stethoscope (Harbor Freight has inexpensive ones) to isolate to the location of the rattle. It typically is worst at cold engine start up.

There are numerous threads about the "death rattle". When it gets bad enough the chain can slip causing pistons to hit valves and bend them.

 

[marragtop]

Yes, keep in mind that the SOHC is an interference engine. If the chain lets go at moderate to high RPMs, you can scramble the valves and damage pistons.

 

[mizestang]

Here's a link to a thread about a common problem that develops with the SOHC V6s as they age. TSB 02-7-6 4.0L SOHC Timing Chain Rattle The tensioner for the chain from the crankshaft to the jackshaft wears out. Also, the chain that rotates the driver side camshaft is located in the upper front driver side of the engine.

Try using a mechanic's stethoscope (Harbor Freight has inexpensive ones) to isolate to the location of the rattle. It typically is worst at cold engine start up.

There are numerous threads about the "death rattle". When it gets bad enough the chain can slip causing pistons to hit valves and bend them.

Thanks. I've been able to find good info on this issue. Looks like the cam tensioners need to be changed.