GC made my LS1 noisy

Messages
35
Location
Louisiana
I have an '02 Z28 with 17,500 mi. I changed the oil using German Castrol (was using M1 10W30) and now I have a distinct clattering/diesel sound from 1000 - 1500 rpms. I assume it's the infamous piston slap I've read about. [Confused] It's never made this noise before, and it doesn't go away when it warms up. I'm going to drain the GC and refill with M1 and see if the noise goes away. Discuss.
 
Messages
656
Location
Massachusetts
Just recently switched to GC and I got some weird reactions. My truck drives smoother and quieter, but idles with a harsh vaibration. I think we are missing an important factor here. A lot of us, myself being very bad, switch oil brands/weights every oil change looking for the perfect oil. We constantly change what the engine sees, and on a molecular level, we are constanly changing the wear patterns. So I would guess that as we keep changing the wear patterns, we are leaving our engines in sort of a break-in stage all the time. I think I will try to run this oil for three full changes. This will be the longest any oil besides M1 has been in my truck.
 
Messages
89
Location
Niagara Falls, Ont.
I wouldn't be so hasty to dump the GC. If anything, now's a good time to take it to the dealer and let the service manager have a listen. A problem is a problem, regardless of which oil 'masks' it. Just my $.02 FWIW, I'm running the GC, and haven't noticed any effects, good bad or otherwise; perhaps better mileage, but I'm waiting a few tanks to pass judgement.
 
Messages
3,845
72sub,I doubt its the oil. The engine was due to begin the LS1 "dance". I think piston slap isn't even a close description to the core of the issue. If we are on to something and it is a oil pump,flow issue it won't matter what oil is used. Only benefit some are seeing is that a thicker vis oil is dampening sound out and or allowing a bit more internal friction and the pump doesn't cavititate or burp as much. The thicker oil may inadvertantly index the pump drive a bit, allowing more normal operation. I think a post by someone with a modified pump and a oil analysis to back it up would be helpful.
 

72sub

Thread starter
Messages
35
Location
Louisiana
I agree with you Terry, I don't think anything is wrong with the oil. I'm still going to dump the GC and switch back to M1 just to see if the onset of the noise is coincidence with the change to GC or caused by the GC. Regardless, I'll be taking the car in (I'll save the GC and put it back in if it's noisier). I've read a lot about the piston slap problem. Mine always had some noise (sounded like valve train noise to me) on cold start up, but it went away when the engine warmed up. This new noise is louder and doesn't go away when warmed up. Also, it's only audible from 1000 to 1500 rpms.
 
Messages
50
Location
vancouver,wa.
I HAVE A NOISE AT 2,000 RPM,UNDER LIGHT LOAD,DOES IT WITH ALL OILS,IN ALL GEARS,ON A 2K LS1 WITH 41K,TO ME IT SOUNDS LIKE #1 CYL HAS A PISTON ROCKING,CHEV HEARD THE NOISE AND REPLACED THE CLUTCH,AND ALL THAT GOES WITH IT,WHEN THAT DID NOT FIX NOISE, THEY SAID THE NOISE WAS NORMAL.THEY DID NOT THINK IT WAS NORMAL,BEFORE CLUTCH,WHEN THAT DID NOT FIX IT,THEN IT BECAME NORMAL.
 

72sub

Thread starter
Messages
35
Location
Louisiana
I put M1 10W30 back in last night. When the engine is cold I can't tell any difference, but when fully warmed up the M1 is quieter. I'm not saying something is wrong with GC, I'm only saying that in my LS1, it's more noisy than M1. I would like to have left the GC in long enough to run a UOA, but I just couldn't stand the noise. The noise only occurs between 1000 and 1500 RPMS under light load.
 
Messages
258
Location
IL
yea! my 01 SS with 24k, last satruday this noise appeared when the engine was totally wamred up... sounds like a knock , rev in neutral VERY lightly and it will come, or if i rev it heavy to 3-4 k it will knock when the RPMS and coming down, 1-2k rpm....
 
Messages
44
Location
Oklahoma
I have found that some oils just sound and work different in certain engines. If the Mobil I is quieter, then I would stick with that oil and never look back. I am going to do a test on the 15W40 RP Long Rider next year in my V-8. I have no noise issues, but looking for the least wear, but still achieve reasonable performance.
 
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