Question about 1999 Chevrolet Silverado 1500
This is a very common issue with General Motors. I have never bothered to try and fix it because it is not causing any harm. It is because General Motors still uses a push rod motor and the cold oil causes it to knock a little until the oil gets warmed up.
Posted on Aug 05, 2008
Mine started at 120,000 miles so i replaced oil pump with a high volume and problem solved also used 5w 50 synthic oil. truck just tured over 300,000 last week
Posted on Mar 19, 2009
I believe what you are running into is the piston slap issue GM has with the newer generation motors (mid 99 up). They shortened the skirts on the pistons to make them lighter as well as coated the outside of the piston with some type of coating (not sure exactly what it is). They run quite for about the first 20 to 30 thousand miles and then it starts to become noticeable on cold start ups and usually goes away after a short period of time. My truck started at 32,000 and it now has 231,000 miles on it and does not use a drop of oil, but it knocks in the morning and knocks on hot days at idle. I have heard some engines sound like a 90's model ford power stroke when they crank in the morning and they run fine as well, just have to put up with the noise. Two things that did make mine better where Synthetic Oil (10w-30) and/or Lucas oil Treatment. You can give a shot and it may or may not help yours out?
Posted on Sep 25, 2008
You have to use the 5W30 oil only, if you change weights it will make noise on start up
Posted on Jul 29, 2008
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Posted on Jan 02, 2017
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