What does the death rattle sound like?

[angstrom08]

A year and a half ago, I purchased a used '01 2WD XLT with 200k miles on it. This forum has been incredibly worthwhile. Reading through years and years of posts has been incredibly valuable. For example, the suggestion to clean your IAC? Brilliant. No more hard starts. Resolving the B1994 airbag code by unplugging the cap, blowing into the connector like an old NES cartridge, and reconnecting it? Again, Brilliant!

Unfortunately, one thing has nagged at me. I've read of the ominous death rattle that precedes the violent and catastrophic failure of the timing chain guides. Unfortunately, inspecting them for wear seems to be almost as difficult, expensive, and involved as replacing the cassettes. But, at 200k+ miles, my truck has it's fair share of unique noises, clunks, etc. So, I was hoping someone who has heard this noise of impending doom would be willing to describe in as much detail what to listen for.

Is it constant or intermittent? Is it high or low pitch? Volume? Should I be able to hear it in the cab? Do you hear it most when idle, driving under load? Does the rattle get worse over time or does it generally just happen abruptly?

Does anyone know of a recording of this?

Thanks

 

[Flash]

The very first sign of the death rattle is at start up before the oil pressure builds up.

The timing chain tensioner has a spring in it that's supposed to apply pressure until there is oil pressure, when the spring gets weak there isn't tension on the timing chain in low oil pressure conditions ie: at start up.

You will hear the rattle, it sounds exactly like a chain rattling across metal, until oil pressure builds up and puts tension on the chain. Until then the chain is thrashing about breaking the plastic guides.
Replacement timing chain kits come with steel backed chain guides now.

It is a good idea to replace the tensioners before you hear a rattle so as to prevent any damage occurring at all. It's not too expensive or too difficult to do and just requires a 36mm socket..

I've heard from some people on this forum that it's difficult to get a tensioner that's any better than the one you're replacing.

 

[2000StreetRod]

multiple timing chain related rattles

The "death rattle" is from a broken left or right timing chain cassette guide assembly. As Flash posted it is loudest at cold engine start. I'm not sure if it's due to worn springs in the hydraulic tensioner. It may be due to the broken guide assembly preventing the tensioner from tightening the unlubricated chain. As oil gets to the chain the rattle gets quieter when the loose chain strikes other metal parts in the engine.
1999 Explorer 4.0L SOHC Bad timing chain rattles

Another rattle is from a worn crankshaft sprocket to jackshaft sprocket (primary) chain tensioner. It usually happens around 2,000 to 3,000 engine rpm. Engine damage from a failed primary chain tensioner is much less common than for the cassette guide failure.

If the vehicle has 4WD there is also a balance shaft chain in the engine. I have a 2WD vehicle so I'm not familiar with the rattle characteristics.