Yeah, I've done a search. I'm still a little unclear on whether this is the sound that I have.

Shortly after it was new, at about 1,000 miles, I first noticed the sound. At idle--cold or warm--the engine has a knocking/rattling sound. It sounds somewhere between valve clatter and a diesel idling. It used to be somewhat intermittent, such that it was not very loud when at the dealership (Murphy's Law).

The sound got worse after the first (dealer) oil change.

With about 10K on the odo, the sound has gotten progressively louder. It is plainly audible at all times when idling. Changing to 10-30 Mobil 1 (with pre-filled filter) did not help.

Is this piston slap? If so, when does it get loud enough that the dealership will be authorized to attempt a fix? Is there any reason to be concerned about engine life?

Thanks,

TLS

 

Does it go away when you raise the idle 100 rpm ???

Does it go away of you pull the supercharger belt ?

If so you may have the Supercharger rattle. Mine started after I put pulley on.. It was referred to here as cavitation. Been doing it for 30K+ and no problems

Doug

 

Nope, "marbles in a can" happens under load if its detonation, not at idle. Pretty much everyone's L makes idle noises, I know mine started right after the first oil change. Hard to tell if its valvetrain or something else. Doesn't seem to effect anything.

 

A friend of mine has the same problem but it is exhaust related. If you push down on the tail pipes it goes away.

 

Maybe you forgot to take that can of marbles out from behind the back seat???? he he he

 

You might want to take off the idler pulleys and clean out the dust seal.

 

Where I live is curvy and hilly and sometimes when im drving up a hill my truck sounds like it has the marbles, it does it right at the point of where the truck would have to downshift to get the speed back up. Is this detonation??? I am usually almost at 0# of boost on the autometer when this all happens. Let me know what you guys think?

 

TYT-LYT, yep, thats detonation. Normally very noticeable under load, often most audible when the engine is lugging at a lower RPM. Often higher altitudes can create the issue even in a stock L, especially if the gas available isnt the best.

 

Well I am stock and the only gas i run in this thing is 93 octane, its never seen less...Is there anything I should do? 2cool, thanks for your help with this.
Keegan

 

If you are stock, then there are a few options available. First is to use octane booster with every fillup. Or you can try changing to a colder sparkplug, such as the TR6. Either should take care of it.

 

2cool, thanks, I was thinking of a 4# later on in the year for my truck, would you say that it is a good idea not to do one due to my truck already pinging? thanks

 

Does anyone else have any opinions? thanks.

 

How many miles on your fuel filter? More than 6 or 7,000, then change your filter--NOW! A clogged fuel filter may/could cause detonation, especially when the eng. is under load(as in your "hill" situation).

Dan

 

TYT: do you hear a slight rattling that almost sounds like an exhaust leak during tip-in throttle (almost no boost, 1600 rpms or so)? if so i dont think that is detonation. i thought i had detonation when i heard similar sounds, but i just went to the dealership and test drove a BONE STOCK 02 off their lot. this was all back in the fall in 50-60 deg. weather. it had the same sound and the service tech who's pretty good with lightnings (the dealership has an 11-second one) said it wasn't detonation. i've also had a few people from this board listen and they say the same thing...not detonation.

 

...and I'm not talking about the felines sleeping in your truck's engine compartment...

Do you have the Bassani cats by any chance, or aftermarket ones made by Catco (original Bassani cat maker) ? Bassani cats are the most unreliable POS made. A trip to the Corral, using the search function on "Bassani Death Rattle" should be sufficient.

Even if they're stock, check the heat shields just in case... they do fail periodically...

just a suggestion...