I’ve a beautifull 1987 B250 Wagon with 70K original miles, engine 5.2L (318ci) . This Van stay garaged for a longtimes. After a serious tune up and change all fluid, i ride 3K miles whithout major problem.
Since one week, when i start cold the main pulley is noisy. After few minutes when the engine is warm, the noise stop. The carburetor is new and the timing ignition was well controled by timing specialist mechanic.
Any idea why the main pulley is noisy when start cold engine ? Also have a very very small oil leak above the main pulley.

 

Main pulley is also the harmonic damper. There is a rubber ring in there that deteriorates over time. If the outer ring is loose, or wobbles while the engine is running, it's time for a new one.

 

Thank you for the fast answer. Before adjust the timing ignition, few weeks ago, around 45 mph i’ve small vibration inside the Van. After well adjusted timing, vibration are 50% less but few again at this time.
Just go back from under the Van for check. Bolts and nuts are pretty rusty and not big space between radiator shroud and belts pulley. I see marks on the side top vibration damper. When installed a new one, marks do be at the same position, right ?
It’s not a cheap part and labor. I see few different vibration damper on Rockauto or Summit. Not sure witch one fit good for my engine.
No noise when engine is warm. This job do be programmed like a priority ?

 

The damper is key on the crankshaft, so, only goes on one way. Makes it easy.

Are you sure its an engine vibration you are feeling? When's the last time it had a tune up?

 

No sure to following what you mean « only goes on one way »
Complete tune up 2K miles ago and spark timing ignition job 500 miles ago.

 

There is a keyway in the crankshaft snout, and a corresponding slot in the damper. Just line 'em up, and slide it on.

 

Okay Hey You, thank you for your help . It’s always pleasant to see you here and give help at everybody.

I’ve now 3K miles with the Van since purchased. Real pleasure to drive. It’s my daily driver. 100% E-85 , more cheaper here. 12 MPG . Change the catalitic for a glasspack exhaust , Nice noise now 👍. Control emission is ok 👌