I apologize if my following description ain't the most technical, but I had to ask someone I know who knows alot more about cars and performance than I do.

A month or so ago, I thought I heard a tapping sound coming from under the hood, and my first thought was the valves tapping, or is it valve stems/tappets tapping. But, the noise was relatively intermittent, so I began to think I was just imagining things. But, then it started coming back, and a bit more consistent and louder.

Now, the issue basically started when the weather started getting colder. I live in southeast Georgia, so it hasn't been really cold, but it has been the coldest since I've had my Vette.

The guy I asked to listen to my under hood noise said that there was definitely some tapping in the valve train, but that it wasn't necessarily a problem. He asked what type of oil I was using with the thought that a thicker oil may lend itself to this tapping since it takes longer to get circulated through the engine when cold. Will the oil have any effect? Should I use 10W30 versus 5W30 Mobil 1 Synthetic?

I am planning on changing the oil tonite and just using 5W30. But if yall recommend anything else confidently, I may try. Thanks for any input. I would just hate to think that I am being overly nervous, but the Vette is new to me. Well, it does have 13,800 miles on it, but you know what I mean. :seeya

 

Hi George,

If you are getting more tapping when the car is cold going with a 5W30 could help - I would say give it a try. You don't say how long it has been since your last change, but low oil pressure and dirty oil can create more noise.

All that said USUSALLY if you are getting rocker noise only on cold starts it means you have a hydraulic lifter that is leaking down and takes a bit to fill up after start.

If going to 5W30 doesn't fix it and the car is under warranty I would take it to a dealer to be safe.

Les

 

I changed the oil 5000 miles ago, and have used Mobil 1 since picking it up at the NCM. I also used a PureOne, or something like that, for the oil filter. It was recommended by the guy at Advance Auto Parts, and was the best quality/performance oil filter they had. Just figured I would add this in case it would help anyone else in giving me some advice. Thanks again.

 

OK then - it is not dirty oil. As for the filter my personal preference is the Mobil 1, pricey but came out on top in independent tests for durability, filtering ability and least likely to mix dirty oil in with filtered oil. The AC UPF filter was also very good, but GM changed suppliers recently and I have not heard of anyone pulling one apart to make sure it is as well built as the old one.

The Purolator PureOne is probably a little better than stock, but it is not causing your problem IMO.

Les

PS: I have to ask - is this a recent problem, i.e. are you sure you are not hearing "normal" fuel injector noise?



[Modified by ZO6Les, 8:27 PM 12/12/2002]

 

Does the noise go away when the engine is at operating temp? If so, it may be piston slap, which is normal for an LS1.