I have a 2000 Excursion 4x4 limited. the engine sounds like it has a rattle at the bottom and when it changes gears going down the road it rattles just before changing out. When parked I can hear it faintly but when i give it a little gas it rattles loud. One mechanic told me it could be the timing chain. What do you think it could be?

did they do an exhaust back pressure test to diagnose a plugged catalytic. if they did then replace it as there is no repair for this. the rattling you hear is the catalyst has come apart and is rattling inside the shell.

Check all the plastic cowlings and air dams to make sure they are not loose and rattling in the wind when you drive down the road. Check the exhaust system for any broken or loose hangers. Hope this helps.

-Possibly valve has too much clearance
-If sound from the valve. Open cover and adjust to specification.


Good Luck
Mai

check for loose shocky rubbers ,loose sway bar rubbers or worn suspension rubbers on that side

Try some engine cleaner and that will help improve rough idle and or performance. To me it sounds like a possible motor mount issue. Sounds like the front engine mount. Because you explained up a hill rattle. / Down Hill\ no rattle. Engine lifts when going up hill and shifts downward while going down hill. hence no vibration because of gravity pull and the weight of the engine.

Yes sounds right, if you have recently had exhaust work done or been four wheeling or ran over something in the road something may have gotten bent and is hitting the under carrage,.If it is a higher mileage vehicle (100 K +) it may be the platnum in the catalytic converter is wearing down and rattling in the encasement, that can be tested by getting under the vehicle when it's cold and rapping the cat. converter fairley hard with your hand and listen for a rattling sound.

solinoid stays engaged. needs replace. the rattle could be a cat convertor bad.

I hope that you had the proper weight oil installed, at your oil change. If your oil is up to the proper level, and it's rattling ,this is VERY bad. White smoke usually means steam in the exhaust, and that means a blown head gasket. Check your coolant level. I wouldn't drive it anymore......until someone knowledgeable can diagnose it!!!!!

Check the heat shield on the catylitic converter,exhaust manifold. Kev-Mn

Sounds like the timing belt tensioner. I have that problem. Rattles at low rpm, goes away as you acceralerate. Looking to have timing belts changed and tensioners replaced.