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The suspension changer
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Discussion Starter #1
I started my truck this morning and it has always been kept up with, regular oil changes and maitenance. Well, I started it and it was tapping pretty loud until about 10 sec later it want away. The oil pressure was fine, the oil level was ok but what in the hell would cause this all of a sudden? It does not do it when you start it up warm but only after sitting up cold for about 3 hrs then it will do it. I am thinking a lifter or loose rocker arm??? I want to keep this truck but I am not sure where to start. I know it nothing major like piston slap or a rod because it's not missing or running weird at all, its just knocking at cold start. Can anyone help?
 

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HOT AIR BALLOON OWNER
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Lifter bleeding down?
 

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The suspension changer
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Discussion Starter #3
I was thinking a collapsed lifter or a bad spring or something.
 

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there is no such thing as the so called gm piston slap. imagine if the piston was slapping the cylinder, how long would that motor last seriously. there is no such thing as the piston slap.
 

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there is no such thing as the so called gm piston slap. imagine if the piston was slapping the cylinder, how long would that motor last seriously. there is no such thing as the piston slap.
You must be a spokesman for GM.....
 

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The suspension changer
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Discussion Starter #6
lol, I understand.. I guess people mean it sounds like a piston slap? But I was really thinking about it and I might just do all new lifters, stronger springs and no better time to do a cam right?
 

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Mayhem, Like Me
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piston slap is for real... chances are though, its a lifter... no biggie, my truck does the same thing. Just let it warm up really well before you take off in it.
 

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there is no such thing as the so called gm piston slap. imagine if the piston was slapping the cylinder, how long would that motor last seriously. there is no such thing as the piston slap.
says the guy who says you need 7" of lift to clear 31's :wank:


dont think lifter swap will fix it... sonds pretty norm IMO

i would think a lifter... youd hear it constantly, not just for 10 seconds or whtever

does it sound like this?

www.pistonslap.com
theresa link to hear it down the page
 

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Mine does the same thing when I start it up cold. It usually goes away before I get to the end of the drive. It's probably a lifter that bleeds down a little but pumps right back up. I'm sure not looking to replace mine.
 

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Bayou Surface Drive, LLC
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Yup like most people do. Hear a lil noise then spend 700 bucks to fix what they think is the problem then it still makes the noise. DO SOME DIAGNOSING PLEASE!
 

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says the guy who says you need 7" of lift to clear 31's :wank:

no i never said that. i just said that you all told me that i would not rub at all with the amount of lift i have and size tires. now my fenders and my tires are fucked. and how do you know that is a credible source. seriously thats just like wikipedia, some one probaly just made that site.
 

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GMFS Sr. Canadian Member
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mine knocks at cold startup if it is really cold out. i dont worry about it. if it breaks, it breaks :hmm:
 

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mine knocks at cold startup if it is really cold out. i dont worry about it. if it breaks, it breaks :hmm:
thats the crank... mine does it as well... cold weather and usually when its humid :shrug:
theres a TSB on it but oh well, even if fixed, itll come back
 

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What's the TSB say?
 

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there is no such thing as the so called gm piston slap. imagine if the piston was slapping the cylinder, how long would that motor last seriously. there is no such thing as the piston slap.
OK, and you are basing this on what? I want to know because a friend of mine had his engine replaced. It started out with "piston slap" when cold and got progressively worse. After 30K, Chevy agreed to replace his engine.

I'd like to tell him that he and the dealer were wrong........
 

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Let's try to get this back on topic. Z71 on 44's truck has started ticking on cold startups only. It's gone in maybe 10 seconds. This certainly sounds like a lifter bleeding down to me. I don't think it's anything to cause concern. Mine does it everytime I start it cold. Mine is not a deep muffled knock like piston slap. It's more of a clack. Might not hurt to pull your valve cover and make sure everything's alright in there. I just had all my rockers out doing my cam and springs. So I know mine's not coming from there.
 

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If it's a loose rocker, it's easy to remedy that. Pull the coil packs off and valve covers off, then make sure each rocker bolt is torqued to 22ft-lbs.
 

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GMFS Sr. Canadian Member
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thats the crank... mine does it as well... cold weather and usually when its humid :shrug:
theres a TSB on it but oh well, even if fixed, itll come back
interesting. what kind of damage does it cause? as you can imagine i have a LOT of cold startups. about half of the year :rofl2:
 
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