4.0L Death Rattle But Only During Warm Starts Not Cold Ones

[Number4]

Maybe I’m missing something here, just scanned the thread. Everyone is talking about the tensioners, I don’t see anything about the guides.

Have the guides ever been replaced? I’ve opened two of these 4.0’s that were making zero sound, and both had busted guides. So don’t assume that no rattle at cold start means anything.

 

[C420sailor]

Good luck seeing the rear guides without taking things apart.

The mech tensioners are a cheap and relatively easy way to possibly improve the situation. If the guides aren’t f’d, problem solved. If they aren’t too broken, they may quiet things down and extend the life of the engine.

When the alternative is to junk the vehicle (very few people are going to have a mechanic do this work—$$$), it’s not a bad idea to throw the mech tensioners at it and see what happens.