I dida remote start this morning (2008 LTZ Suburban with 5.3L) and went outside about 5 min after starting and the engine had a tapping sound that kept time with the engine speed. Not a terribly loud tapping, but enough for it to bequite noticeable. Not a typical at all for this engine, in my limited experience with it. The sound went awayafter another minute or two. I checked the oil quantity and it was just right. I'm running Amsoil 5w30 with about 1400 miles on it. Mobil 1 filter. The engine has 3200 miles total.

Anyone experienced this? Should I have it investigated further?

If it makes any difference, I completed a 400-mile drivealong somemountain highwaysyesterday. This was the first time it had been started since completing that trip. Thanks for any info.

 

I suggest checking your oil level...

 

I think he said he did. I thought the same thing.

 

I hate it when I skip words when reading stuff.... Damn.

My next thought (I guess it's my first thought) is that it's not a tapping sound but rather the injectors firing. I hear a slight tap-like sound on mine as well (07 LT3) and now it's just commonplace.

 

Could be but injectors make more of a clicking sound. I thought maybe a weak lifter (leaks down) or piston slap. Guess it depends on just how loud it is and whether it goes away when it warms up.

 

It does go away when it warms up. It just did it again this morning. I'll change the oil again today in case there's some problem with the Mobil 1 filter (I doubt it). I revvedthe gently to get it warm faster andthe ticking soundwas gone by the time the water temperature started to rise, about 3 minutes after starting.

While I'm buying oil change supplies today, I'll get one of those stethoscope things so I can hopefully hear whether it's in the engine or maybe an igniter or accessory. It sounds like metal tapping, but possibly it's something else. Thanks for the replies.

 

Why not let the dealer do the oil change

 

Exhaust Leak maybe?

 

With a stage name of "sayaltitude" and using words like "igniter" makes me think you may be an airplane guy?

Don’t worry about the noise too much so long as your oil pressure is good when the tapping is occurring, many times these types of sounds are normal and vanish as more miles are accumulated.

Dave

 

It's strange. It does it for three or fourminutes in the morning only. Not a peep the rest of the day, not even if the engine isnice and cool. Weird. I'm thinking that if it were a valve or something else serious, it would do it at each startup for a moment or two. But it's only done it the past two mornings only on the first start of the day and then silent the rest of the day.

Anyway, I'll look and listen some more and if I can't find a good answer, I'll take it to the dealer this week. Thanks for all the replies.

ZX1: I operate Mad Dogs (MD88s) when I'm not tracking down stray tapping noises. How about yourself?