engine and drivetrain Rattling problem, possibly drivetrain?

[chuncomunco]

Hi guys, before I mention my problem, i'll like to thank you all for helping me solve some kinks along the way during my engine rebuild last year.

Problem:

Alright, so its been almost a year since my rebuild and the car ran fine up until 3 months ago. The car started making this really annoying rattling noise. It sounds like 2 pieces of metal touching and vibrating very quickly.

Whats weird is that it only rattles when I decelerate or anytime I let off the gas or if i'm cruising and it finally stops rattling when I step on the gas or if the car comes to a complete stop.

Is it possible that it has something to do with the drivetrain? center bearing? driveshaft?

I checked the clearances of the exhaust from headers all the way back and they are perfectly free from any obstruction.

It really bugs me out everytime I drive the car, its loud to the point that if I pull up to a car show people stare at me! lol

help me please!

[bcthomas122279]

That really sounds like an exhaust issue to me....check again.

[jgerock]

Can you use a stethoscope or long screwdriver to pinpoint the noise (car running up on stands)? I know you mentioned it mainly happens on decel. Loose clutch housing coverplate? Exhaust rubbing somewhere?

Did you bleed the timing chain tensioner piston after the rebuild? How tight was the oil pump chain?

Reason for asking the last one: My engine was "rebuilt" by a PO back in 2003 and I just pulled the head and oil pan to discover the oil pump chain has some serious slop.

[JerryC]

Could be a broken baffle inside the muffler. Our Volvo did something like that and it turned out to be a broken heat shield.

How 'bout the transmission exhaust bracket - is it loose?

Don't know how your engine is - stock or what? The aluminum warm air plenum on the exhaust manifold would rattle like hell if it was loose or missing a bolt.

My tii had a nasty vibration once - turned out to be the starter-to-intake bracket was broken.

Could be your engine mounts - is the clearance okay on the stop plate for the lower engine mount? All those parts tight?

Keep digging, you'll find it.

[spbryant]

I had a similar rattle that turned out to be the gas pedal vibrating against the metal piece it fits into. The rubber on both the pedal itself and the linkage had worn away. It only rattled on decel because that's when my foot came off of it. Not sure if your rattle is inside or outside - sometimes hard to tell. Hope that helps.

Scott

[spbryant]

I had a similar rattle that turned out to be the gas pedal vibrating against the metal piece it fits into. The rubber on both the pedal itself and the linkage had worn away. It only rattled on decel because that's when my foot came off of it. Not sure if your rattle is inside or outside - sometimes hard to tell. Hope that helps.

Scott

[pkbinplano]

Check your guibo bolts