I purchased a 2000 Z28 in Nov of 05'. It's been the most fun I've had in years. (next to the years my sons were playing in little league baseball). Anyway, the dealer had changed the oil, oil filter, as well as the air filter, prior to my purchase. Pretty cool I think. When it came time for an oil change, I bought some Pennzoil synthetic, as Pep boys had an good deal on it, and a rebate. I park on a hill, nose of car facing upward everynight. The car seemed to run/idle a little smoother and was more quiet at idle with the newly added pennzoil.
When it came time for the next oil change, I went with Moble 1 synthetic. The "good" stuff. 15K between change stuff, though I could never go than long, 5-6K max for me. Since moving to Moble 1, the top end seems to make an aweful racket in the morning. Giving it 2-3 min warmup time doesn't seem to make much of a difference. I head uphill for about 1 city block every morning, and I cringe all the way. Klackety-klack from what sounds like the top end for a block or 3, then it quiets down.
Now let me assure you, I don't work for pennzoil, or any other automotive related company. No reason to create what I might consider a really bizzare story. I'm just kind-of shocked by this. My neighbors must think I'm totally weired out, as I have this sick looking cringe on my face all the way up the block, freakin' at the noises coming from my baby.

Could the reason be mechanically based, but timed to make me think it's got something to do with the recent oil change? Could I have a suddenly dying/weakening oil pump? Both oils are 5w-30. I haven't notice any significant change in the position of the oil pres. gauge. I'd expect some type of drop in those readings if pump related. The car doesn't use oil excessively, less than half a quart in 2-3K. No changes in any of these things with either oil, except the metal klackin' away.

Sorry about the long post, but I'm totally confused on this one. My one quick thought has been to change back to the Pennzoil, just to see if things quiet down. I used Napa premium oil filters with both changes.

Any insight or pointers on this will be appreciated!

I'd just like to mention I've spent many hours lurking and learning from the folks on this board. I don't really know squat about the LS1, and appreciate all the posters that help make this an informative and entertaining resourse. Thanx much for all your efforts and contributions to the board.
Jack

 

I've moved away from Mobil 1 after several oil junkies posted the analysis report the received from sending in a sample (they weren't impressive...at all). Personally, I like to run Syntec. I'm considering giving Penn. Platinum a try next time around. But, I won't go back to Mobil 1. The 30w is a bit on the thin side compared to others.

http://ls1tech.com/forums/showthread.php?t=226637

 

I think my car was noisier with Mobil 1. I don't use it any more.

 

Louder valvetrain is normal. Welcome to the LS1.

 

Mine's a little noisy in the morning when it's cold out but the noise goes away after the motor starts to warm up.I've heard that's not unusual for an aluminum block motor.When the temp is higher there is no noise

 

It's always been my experience that when something works for me.......I don't change it!

 

try a thicker oil

 

with better results. Parking in the same position, (uphill) upon startup, the engine makes a little less noise, but is still bothersome. Thing is, it doesn't continue nearly as long as the higher-end Moble 1. It takes less than half a block for the engine to quiet down, to were I don't notice it anymore.

I appreciate all the feedback folks. Thanx!

Steelerfan, you wouldn't believe the "can of worms" I opened up at the local Autozone with the aluminum block thing. Your suggestion "I've heard that's not unusual for an aluminum block motor", I found really interesting. I don't know much about the metalergy side of things, but it kind of makes sense. My son has a couple long time buddies working at an autozone close to my home. I went over there for the Syntec, and metioned it to them. A guy in a Corvette jacket overheard. He was with a guy in an 70 GTO/Judge. A couple of younger guys, one in an Evo, another in some kind of tricked out Honda all got involved in the discussion. The older/muscle car guys were in agreement. The corvette guy mentioned he had an late 80's vintage vette, with an iron block, and when he bought his 94', and did his own first oil change, he said he noticed a big noise difference. The guys driving imports, (no pushrods) said we were a bunch of senile old guys, that are suffering some kind of hearing disorder. Aluminum blocks rule.
I had other things to do, and couldn't hang around for too long. It was a scream listening to these guys go at it. All commerse ceased at this store, as people that were there brousing had to stop and take in the craziness. There was no malice, as these were car guys getting into all sorts of bizzarre discussions. Very Cool. I left before any definite conclusions were drawn.
Thanx Guys!
Jack

 

I assume you used 5w-30 in the Castrol.?

 

The German Castrol that everyone talks about is the 0w30 and say's "Made in Germany" on the back.

 

Yep, 5w-30. Used the same filter as well. I've noticed a perceivable difference running the moble 1 or K/N filters. Presure doesn't seem as high with these, at least according to my guage.
Carquest's premium oil filter is what I usually use.

Jack