I've asked about a small engine rattle I have before, but now I have more information so please bear with me.

At low RPM's (when trans is in drive and stopped a light or something 600 RPM's) there is a rattling sound coming from the engine compartment. If I put the trans in neutral (RPM go up to about 900) the sound stops.

I checked the supercharger pulleys and found that with the belt on the whole belt assembly will rock back and forth about a 1/4". I took the belt off. The supercharger doesn't make any sounds, and the idler and tensioned pulleys are nice and tight, but the lower pulley will rock back and forth about a 1/4". Is this normal? It is the stock pulley, and I would think that it should be tight (no rocking). Sorry if this doesn't make any sense.

Please help!

Thanks for the advice.

Carson

 

its not normal, the stock lower pulley should be tight as well, if it has some play in it, its either loose or has a bad bearing or something, but its deffinatly not normal.

 

That is deffinatly not normal. Did you buy your truck used? IF so the previous owner might have had a bigger lower pulley and put the stock one bak on but not tight

 

Thanks guys.

I purchased the truck used back in September. It's a 2000 with about 50,000 miles on it.

I'll go home and check the lower pulley.

If it is loose is there just a nut in the middle to tighten or do I need special tools?

 

You will need to buy a 14mm allen head socket, if its the stock pulley and normal socket for the cage legs.....Sears.

It sounds like its loose., but the cage legs would have to be loose also so I think you have an aftermarket pulley. Also, if you have a cage around your pulley and that will help confirm its stock. ( some aftermarket pulleys have cages)

If its attached with three 5/16" allen head bolts it is an aftermarket pulley.

They will come loose and when they do they start to make a "ticking" sound that gets confused with an exhaust leak or loose plug.

Also some aftermarket pulleys have the heads of the 5/16' allen head bolts riding in the radius of the pulley and this will prevent proper installation. These pulleys need to be burnished to provide clearance for the allen head bolt.

 

the stock pulley will look like this.........
and the 14mm allen head socket is in this pic also. (gold)