OK Guys, I have been reading your posts for a while, and haven't seen this particular thing yet.. So here it goes, any and all help is very much appreciated.
In Jan of this year we bought a 2003 CTS with ~40500 miles on it... Didn't drive it much until here lately, as the weather in Pittsburgh isn't for rear wheel drive vehicles if you can help it.

Lately it has been making this clicking noise out of the top of it, almost like valve train noise. I got the oil replaced with Mobil 1 synthetic and filter, and it went seems like it went away for about 500 miles. Then it started making it again, so I went and bought some lucas motor miracle oil, put some of that in and the noise stopped again.. Here it is about 1000 miles later and I am starting to hear it again.. Engine has alot of power, and doesn't have any problems starting or running. It does have a slight lop when at an idle, not like a "miss" per say, but almost with rhythm. It has not thrown a code, and seems to be fine running, and it isn't loud but it does get faster with RPM...

In addition to this my wife wants to take it to Cleveland tomorrow, and though I will probably let her, I always worry about little clicking sounds. Any ideas would be very helpful and appreciated.

Thank you!

 

i may well be totally wrong, but what concerns me is that the clicking goes away everytime you ADD oil which usually goes through the valve train first. One shouldnt hear any difference after adding oil.

Is it still in guarantee? take it in and have it checked for lubrication on the top end. it is not unheard that something in the oil system gets plugged top side .. rare .. but still.

 

no its not under warranty any more, I was wondering if there is a way to test to see if oil is getting to the top end of the engine correctly? I can't believe its completely dry, how hard is it to remove just the covers to see if it is tore up?

BTW, Thank you for the reply!

 

I'm probably not much help to you and I realize your post is a few months old, but I'm having the same issue. I'm wondering if you have resolved this issue and if you have any info of what the problem may be. Any help is much appreciated!! My vehicle is the same year with the same engine with 86,500 miles. Also I noticed the sound almost all-of-a-sudden.

 

This has been a common problem with all GM engines that get a little gummed up over time. Next time your down a quart on the oil and ready for an oil change, pour in a quart of ATF (automatic transmission fluid) then run the engine for about 30 minutes then change the oil. There is a lot of products on the market for this but ATF has been tried and true for many years.
Bob

 

Had this issue with Mazda V/6's years ago and it was generic oil filters that had no check valve within them. Would allow the lifters to drain back. Get a DELCO filter if it doesn't have one and change the filter. I am not a believer in any "snake oil" additives. Are you using the recommended oil weight?