Hello Gang. I have an '03 C5 I just bought in Feb. I've driven it about 800 miles since I got it. The last two outings, I've notice what sounds like alot of lifter noise upon start-up. As soon as the engines warms to normal temp the noise deminishes considerably and the engine sounds normal. I did not notice this when I bought it. The only thing that has changed is that about 3 weeks ago I changed the oil and filter. Used Mobil 1, 5w-30. Is this initial lifter noise common or unusual?
Thanks, Dave C.

 

Could have a lifter on it's way out..could be piston slap as well.

 

It's normal. Almost all of them do it. Could be a little piston slap or lifter noise. As long as it goes away when it's warmed up, I would consider it normal for an LS1. No smoking or oil burning, you are OK.

 

List where you live and maybe some one can take a listen for you. Sometimes what you try to explain can sound like something minor when infact it could be an issue or visea veras. My stock ZO6 made ZERO valve noise and even after my major cam install, I very little noise.

There are some cars with piston slap when dead cold and that goes away when its at normal operating temp.

Talk to a C5 owner in your area and compare notes.

Im always available to any of the northeast CT, RI, NY, NJ for help.

BC

 

Thanks for the replies. I've been driving and working on my old '70 for 25 years now and it is quieter on start up than the '03. My '70 will give me a few lifter rattles in the spring when I drag it out after a long winters sleep. Especially when it is cold in early spring. But this noise in the '03 seems to be across the board on both sides of the engine. What really has me anoid is that I don't remember this when I bought it. It only has 9000 miles on it. Two things I've done, one was to change the oil, and abought the same time I'm concerned that I might have over rev'd it once. And only once. should be able to take it but I'm paranoid now, having bought this new thing ya know. I was coming through a intersection on a country road, made a left turn, pulled it into 2nd gear and punched it. I'm not use to how fast it picks up the revs. It seamed in a instant it felt over rev'd, i didn't get a chance to see the tach I was to busy watching where I was going. I really didn't stand on it that hard, but now I'm not sure???? Surely it should take alittle extreme pressure. Anyway, now I here this noise and I'm worried. Maybe it was always there, and I just never started it with the door open before.
Thanks for your help.
Dave C.

 

DAVE

Where do you live??

BC

 

You just have to love this guy !

 

An over rev can bend pushrods but I would check a few things before going into the motor. These motors will build carbon and this can cause the pistons to rock. Since the 03 has the coated pistons, perhaps a de-carbon is in order. Mine did this after a drive back from the NCM pooping along in 6th gear. The other thing you can try is a different oil. I found that the German Castrol 0W-30 provides for a quieter engine in general and is a higher viscosity than the Mobil-1 5W-30.

 

Perhaps you should consider driving the car more often especially if your weather has improved. With only 800 miles accumulated since your February purchase one can assume the engine sits unused for considerable time. It doesn't seem unreasonable that one or more of your lifters bleeds down during that no use period especially considering the noise ceases after reaching operating temperature.

Perhaps there are other issues but a partially collapsed sticking lifter, bent pushrod or broken valve spring symptom typically wouldn't go away after attaining operating temperatures. Also, your brief accelleration into higher RPMs would have been protected by the preset rev limiter -- overrev on downshifting is a whole different matter. Just a consideration. Good luck...

A1

 

Try running a can of Techron through it. A sticky injector can sound just like a lifter.

 

I tend to go with the bleed down of the lifters. during good weather I try to get it out at least once a week.
But sometimes it has been setting for 3 weeks. That doesn't seem too excessive to me cause the oldchev can set for much more than that and have no issues upon start up....except a dry Quadrajet which needs cranked like crazy to get to squirt fuel.
My feeling about this '03 is that it didn't make these noises a month ago. And I don't remember hear the noises when I bought it in February. It was setting in a back row of a Chevy Dealership out side. If I had heard these noises, I don't think I would have bought it.
I don't know what oil was in it when I changed oil 3 weeks ago. I put in 5w-30 because that is what the owners manual and the Corvette Mechanic at the dealership said to use. the alternate oil specified is the 10w-30 if temps don't drop below freezing I think. Well I won't be running it when temps are below freezing and it never gets below freezing in my garage, so maybe if I change the oil to 10w-30 the noise will go away?????
Dave.

 

My '01 Z does the same thing. Soon as it warms up a bit the lifter noise goes away. I've been driving it this way almost since it was new and now with 25k has had no adverse effects. Either its a sticky lifter or it bleeds down while sitting. I don't think you have anything to worry about.

 

The "30" in the oil viscosity is actually a range that extends from 9.3 to 12.49 Cst. The Mobil-1 5W-30 or 10W-30 has a viscosity at 100* C of 10 Cst whereas the German Castrol 0W-30 is 11.7 Cst. The Mobil-1 is close to a 20W whereas the German Castrol is close to a 40W. No guarantees, but an oil change is simple and you may find it helps since you hadn't noticed this noise prior to the oil change. Filters can also play a role as some are more restrictive than others. The GM UPF-44 is very restrictive.

I would also Seafoam it prior to an oil change as carbon build-up will cause a noise that is indistinguishable from piston slap.

 

Dave that sounds like normal small block chevy pistion slap.

Just let your car warm up 1-2 min then drive off

 

Vettenuts,

What does the "Cst" stand for? I'm not familiar with this term. As far as filters go, is there a good spreadsheet that shows to spec’s for different brand of filters?

The last oil change on my vett I used Mobil 1 0w – 30 only because that was the only viscosity on the shelf at the store, poor reason I guess. I have notice on cold start a little be more piston slap type noise then with 5w – 30. The noise is gone after a minute or two of starting. Never get it other than the first cold start in the morning. Anytime after that I hear nothing.

As far as the carbon build-up noise you spoke of, does the noise go away after warm up or is it always there?

 

I had the lifters bleeding down when cold but it didn't happen till like 274K miles. Not saying that it can't happen but from reading lots of posts here on the forum, there haven't been many lifter failures. Mine were simply worn out and certainly the cause of my sounds. So, if it is this cause, I had; tapping when starting up when cold and would go away within seconds. Over time, the tapping would last longer and then it would take till the engine temp started rising on the analog guage before the tapping would stop. Did not sound nice. Finally, the tapping suddenly got loud and it was time to take down the top end. Replaced all of them, rockers, pushrods, springs, seals and had the valves done. No more problems. Again, I really doubt yours would be failing but it can't be ruled out either.

 

Thanks everyone. The noise goes away when the temp gauge get to about half way to normal, around 100 degrees. I think I will keep an eye on it for awhile. Different oil might make a difference but I don't really know which way to go. I've had some tell me that the 10w-30 is not the way to go. And that the 0w-30 is. too bad I don't know what oil was in it before I changed it.
Thanks again.
Dave.

 

Dave if you live in the south, 10-w30 would be a great option.

only use 0-w30 if you live and drive in the far far north

 

Please explain why, the viscosity of the German Castrol 0W-30 exceeds Mobil-1, Amsoil and Royal Purple.

 

centistoke (cSt): unit of kinematic viscosity