I have a light tapping sound in my 01 when I start it. It goes away within a minute or so. Do I have piston slap, or not? Thanx. :smash:

 

It probably takes a little time for the oil to get to the lifters. Check your dip stick and make sure you are full, 6.5qts.

 

We're just guessing... since we can't hear it. But it's most likely a stuck lifter not getting oil as well as it should. I've had 6 350's in various cars since the mid 1970s and several developed lifter knock. Unless it's severe, you won't notice a miss or dead cylinder. Take a WOODEN yardstick and use it as a stethoscope. Put one end against your ear and move the stick along the valve cover of the side you think is tapping, cylinder by cylinder. That will help you locate the exact location of the noisy lifter and confirm whether it's on the top half or lower half (lifter or piston) of the engine.

Other speculations on what it could be:

Slightly bent pushrod (usually from over rev, or high rev without being under a load) and isn't seating on the rocker arm accurately - but this malady is usually accompanied by a steady miss because a valve isn't working 100%).

Clogged pushrod which is prohibiting oil from getting up top to the lifters as fast as it should (thus the sound going away shortly after starting - this one makes sense and I'd bet money this is your problem).

Piston slap - but I doubt it unless you have one or more of the following conditions: Used the incorrect oil, or don't change your oil regularly, or have used STP or other oil additives which can thicken up the contents of your oil pan and turn it to goo / sludge, or have installed a blower or turbo and are forcing air into an engine running over 10.5:1 compression, or have just used the NOS a bit too much. :)

Assuming it's a lifter, the remedy would be to identify the offending cylinder or lifter and replace what's noisy and whatever caused it. In some cases simply replacing a partially blocked pushrod is all that it'll take. Or you may need to replace the lifter set if you can't identify a bad (or plugged) pushrod. If you pull the valve cover and run the engine in an attempt to identify a plugged pushrod, or to hear the bad lifter better, make sure you have lots of rags nearby to lay over the top of the rocker arms. Else you'll have oil all over you, your front fender wells and your fenders. Have lots of oil pickumup on your garage floor too - just in case some gets around the rags. School of hard knocks taught me that one many years ago.

Good luck with your gremlin sound! Remember that if you identify it as a lifter on the top of your engine by using the yardstick, you CAN choose to do nothing as long as the sound goes away eventually once she warms up, and/or if she's not missing. It just depends on how annoying the tick-tick-tick-tick is to you individually. :)
Gunny

 

This topic was covered many times after the '01s were released. The sound is normal. For some reason the '01s have a bit more mechanical 'clatter" at start up and like you said, goes away after a minute or two. Late in the '01 run (April) new larger diamater (few mm) teflon coated pistons were put in supposedly eliminating the piston slap sound. Nothing wrong with your car.
:cheers:

 

I won't say whether it is or isn't, but my Pontiac has had piston slap since new (it's a 94) and it now has over 100K on it and still runs like a bear. It has always had Mobil-1 oil too, so I think that helps to some degree.

 

zoomie,

Sounds to me like you have some piston slap. Fairly common. I think the pistons are cam ground and have different expansion rates parallel and perpendicular to the axis of the wrist pin. As the piston tends toward operating temperature, it gains a more round rather than elliptical shape. Sounds like yours isn't very severe if it goes away in a minute. I think a collapesed lifter would pump up in less time than a minute. But as someone mentioned above, we are just taking our best guess. :yesnod:

Good luck.
Mark

Mine does it, too.

 

Mine also makes a noise, sounds like a light clatter from outside the car, sounds like a diesel engine inside the car. Funny thing is, is does not start until the engine has been running for about a minute or two, goes away a few minutes later. Someone posted that this kind of noise is from one of the engine accesories, or injectors.

 

Appreciate all the insight. I guess it's one of those "Vette things" that we all eventually learn to live with. It got down to 15 degrees here in Memphis last night, and when I started it this morning I didn't hear it. An oil viscosity issue? Who knows, as long as it isn't going to self destruct 6 months after I pay it off. Thanks again for your time and insight... :flag

 

Jim,

I think some members have reported hearing a noise from the vapor canister solenoid on startup. Guess it could be unplugged temporarily to see if it is the culprit.

Good luck.
Mark

 

Thanks for the info. I may try unplugging it if the temp ever gets above freezing in my garage.

 

Ironic or coincidental....it's defenitely the later....I was going to research/post something today on the same thing. My 2000 starting making the tapping noise on Saturday am, scared me a bit and it went away after a couple of minutes. Same thing yesterday am and then again today. Pissed me off that something's up, but I'm happy that the sound definitely goes away once the oil is being pumped around. Called for an appt to let the dealer look at it since it's still under warranty.

I recently added a Vortex, duct and MAF and am wondering if that could have had any contributing factor to this and keep thinking no...induction is induction and the block's the block....

Everything else is cool to; oil pressure, oil level, temp. etc

Suspect a bad lifter or a clogged one...

Advice from my new mechnanic was 'to drive it a little bit', perhaps whatever is hampering the lifter from doing it's job, may get free and then maybe the noise will go away. Second step if necessary (probably) is let the warranty take care of it.
:(

 

Many on the Forum indicate the clicking comes with cold temps. I live in South Florida and get the noise on cold (70 degrees) starts which disappears after a few minutes. I have an '01. :smash:

 

Mine's at the dealer today. I'll forward the info once I get it. Was extremely nice when I brought the car in last night (so that they could hear the problem first thing in the am when it's cold) and the service advisor guy was nice back; parked the car inside the garage instead of just in the lot behind their fence....who knows, maybe it's all a good sign.... :flag

 

Well guess what.....you know those times that something's happening to your car and when you bring it in, it stops doing it??? That's what happened...the tapping is gone.

I have to believe what Ted from Valaya in San Jose told me (highly recommended for anyone who needs work in the SF Bay Area) - he said drive it for awhile and whatever is causing the lifter to not work properly may get jarred loose - it may fix itself. Well apparently it did.....

So for anyone that's having this problem, try putting miles on the car before taking it in. I put about 150 on my car and now the noise is gone...

:cheers:

 

my 02 does the same thing,my 97 and 99 did not do this. they made the pistons shorter to cut down on the friction and GM has done this on all their engines. i had a rental 02 pontiac grand am with a V-6 while in FL last month and it also had piston slap when you first started it in the morning. the GM tech website has TSBs on some of the engines.

 

I've got the same symptoms on my '99 Coupe w/ 18K miles. Starts up sounding fine, starts clicking after about 30 seconds, lasts until I'm down the road a bit.

Sounds like lifter noise on the right (from inside the car) side. But if it's a lifter how come it's quiet initially? :crazy: A bad lifter *should* be noisey immediately.

After it's warmed up the car runs great. Occasionally I've heard it after driving it and parking it for >2hrs. Sounds 'diesally' for a bit, then quiets down.

I HOPE its not gonna become a problem, but I bought extended warranty just in case.

BTW, there are some guys taking issue with GM over this. Check out:
http://www.ls1camaro.net/ls1knock/index.asp

 

Kind of an annoying web site, but I thought it had some pretty interesting information. I haven't noticed it on either C5, but I do hear some noise in my Tahoe. :cry http://www.angelfire.com/tx5/gmpistonslap/index.html