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Lifter Tap When Cold

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turbojimmy

New member
Our newly acquired '03 GTP has a pretty loud lifter tap when it's cold. It has 72k miles on it. It takes a few minutes at idle to go away, or will go away almost immediately if you rev it up a bit a couple of times or simply start driving it. It doesn't do it when it's warmed up if you restart it within an hour or so. The duration of the tapping depends on how long it's been sitting. So I'm thinking leaky lifter(s). The oil looks good and I'm not losing any coolant, so it's not an intake manifold thing. It's definitely not a bearing sound (been there, done that, got the t-shirt). My Avalanche has been tapping when cold the entire 7 years I've owned it so I'm not terribly concerned about this thing. But...I'm wondering if heavier weight oil would fix it. The previous owner has always used Royal Purple in it so I'm wondering if it's the thinner, synthetic oil that's contributing to the tapping.

If I were to go about changing the lifters, it does not appear to be a bad job assuming I can get the pushrods out of the RH cylinder bank without them hitting the firewall. Is this the case?
 


my car would do this when i was over due for a oil change. i started to run 3 qts of 10-30 and 2 of 10-40. never did it again unless i was way over due on a oil change.

issue is a lifter is bleeding off. you can change em but gm says its ok as long as it goes away in a minute or so. you can get the push rods out easy too.
 
Scottydoggs said:
my car would do this when i was over due for a oil change. i started to run 3 qts of 10-30 and 2 of 10-40. never did it again unless i was way over due on a oil change.

issue is a lifter is bleeding off. you can change em but gm says its ok as long as it goes away in a minute or so. you can get the push rods out easy too.
Click to expand...

It takes a bit longer to go away if you leave it idling - closer to 3-5 mins. But it does go away immediately once you start to drive it (higher RPMs). My truck gets louder when it's overdue for an oil change as well. The oil change monitor on the GP says ~50% and the oil on the stick looks like it's right out of the bottle. I'll do a mix of 10-30 and 10-40 the next change and see how that goes.

Thanks!
 
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