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Tapping noise

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Old Mar 6, 2011 | 03:22 PM
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Default Tapping noise

I have a loud tapping noise on cold startup. When oil temp gets to 160 it can only be heard from outside car with hood open. I have removed all rockers and pushrods. They look good and I don't see any broken springs. I used a stethescope and the tapping is loudest at the waterpump and front cover. All belts were removed and no change. I don't think it is piston slap because it lasts too long and never stops. Thanks for any advice.
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Old Mar 6, 2011 | 04:30 PM
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piston slap... very common on LS1 http://pistonslap.com/
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Old Mar 6, 2011 | 05:20 PM
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I encountered a tapping noise last month and swore it was a lifter. But I found a loose spark plug. Go figure?
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Old Mar 6, 2011 | 06:20 PM
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How many miles on the clock? I had a lifter(s) go bad on me but it wasn't till way up there in miles...270k range, replaced lifters at 274k. Mine started by tapping briefly when cold then go away quickly. The tapping time progressed as time went by till it wouldn't go away till the engine started heating up. Then all of a sudden, it became loud. Tore down the top end and replaced lifters, springs, rockers, pushrods, guides, seals and all needed gaskets of course. No more problems.
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Old Mar 6, 2011 | 06:30 PM
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30,000 Miles. I do have some piston slap but it only lasts for a minute.,this is much louder and never stops.
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Old Mar 6, 2011 | 06:52 PM
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Might want to pull your codes in case of a misfire taking place but sort of sounds like a bad lifter...really bad. Might try doing a compression test to verify and expecially on the #1 or 2 cylinders since you are hearing it up front.
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Old Mar 7, 2011 | 06:25 PM
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No codes. On cold startup when the noise is loudest at water pump. When I put the stethescope at a point where the head meets the block near the lifter area the sound is much quieter. When I first heard the noise I thought lifters. After using the stethescope I am not sure.
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Old Mar 8, 2011 | 05:00 PM
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Originally Posted by PF597
No codes. On cold startup when the noise is loudest at water pump. When I put the stethescope at a point where the head meets the block near the lifter area the sound is much quieter. When I first heard the noise I thought lifters. After using the stethescope I am not sure.
try running it with the drive belt off,but ony long enough to hear if it goes away could be the water pump
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Old Mar 9, 2011 | 02:05 PM
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I had all the belts off. No difference.
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Old Mar 9, 2011 | 08:17 PM
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do a compression check i had a collapsed piston do that! ran great but had low compression on that piston and tapped all the time
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Old Mar 9, 2011 | 08:33 PM
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When I first started reading your post I thought piston slap but once I finished I think it isn't. Piston slap goes away once the engine is warm. Piston slap noise usually disappears once the oil temp is in the low 100s. It will be loud for quite some time if the engine is idling and warming up but as the oil temp comes up it will all of a sudden diminish in volume until it can't be heard over the space of 40 to 50 seconds.

Bill
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