I have a 2009 GMC 5.3 with valve noise real loud on cold startup then gets quieter after running a moment but stig a lot of clicking
It's one of those things, you may have a mechanical problem with the valve train (lifters, valves, rockers, etc) or you may want to try some type of oil treatment. Oil returns to the pan when the engine hasn't run in a while, oil treatment may keep the heads lubricated better for that first start until the oil pump can build up pressure. A good degunking may help too. There are plenty of products to add to oil to degunk an engine. Hopefully in your case that is all you need.
Thanks I will try the additive but I only have 41,000 miles on it and the oil was changed two weeks ago at the dealer where i bought it
I agree with Ken had a bad valve tap and used Lucas Engine Oil Stablizer tap was gone after letting vehicle idle for about 45 minutes to an hour.
My old Acura SLX would click really bad on cold mornings, I used a quart Marvel Mystery Oil at every oil change, it didn't completely cure the problem but it did quiet them down a great deal, after about 15K miles I finally replaced the lifters. You may also want to make sure you have the right oil filter on the engine, it should contain an anti drain back valve.
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