GuitsBoy

iTrader: (4)

Hey all.... Got an oil question.

I know the ls1 wears best using a thicker oil, however since ive switched over to it, i get some hellacious piston slap or lifter noise in the mornings. My first few oil changes in the car were M1 5w30, and the car was plenty quiet on startup. After that I started the 5:1 5w30 15w50 mix, and the car started slapping a little in the mornings, so I moved to M1 0w40, but the slapping continued. The last few oil changes have been with GC 0w30 which is much thicker than M1 5w30, and my slap is still there. I want to try going back to M1 5w30 to see if it quiets down the engine, however, i really dont like the idea of putting in such a thin oil again after all the trash talking about it and all the good reviews and oil analysis of GC lately. What should I do?

Also, even though im calling this piston slap, I have a feeling its actually lifter noise. On a cold startup, it takes about a minute for the rpms to drop from 1150 to 1050 and thats usually when i start getting my slap noise which stays there till the car is fully warmed up. Now if i rev up the engine slightly to 1500 RPM for a couple of seconds and then let off, the slap noise is gone but gradually comes back over the next 20 seconds. Does this sound like the lifters are pumping up with RPM at initial startup or if i give it a touch of throttle, but then when I release it they bleed down? If this is the case, should a thinner oil pump up quicker and stay pumped up? At startup I have 60 psi oil pressure, at hot idle i have about 45. Also, is there an oil that has a truly thinner viscosity at low temps but still gets thicker at operating temp? Its my understanding that at 0º F, mobil1 0w40 is actually thicker than 5w30. Do i have another option? How is the new 0w30?

Thanks!
-Tony

technical

The thicker oil is taking more time to get to the top of the motor. What you described is not that uncommon especially in NY this time of year (30-40*). Put the thinner oil back in until summer. Or just be sure to let the car warm up real good before taking off. Otherwise you'll be negating wear "savings" of the thicker oil.

GuitsBoy

iTrader: (4)

I always let the motor warm up to almost operating temperature. atleast to the 1/4 mark on my broken 2002 temp gauge. I cant imagine it takes a matter of minutes for oil to make its way to the lifters... Anyway, i might try running some mobil1 5w30 one more time to see if it quiets down. If so, Ill have to look into running something a little thinner than GC. Thanks for the reply, technical.

blackbird007

iTrader: (1)

Yeah I never had piston slap or lifter noise. Then I switched to GC 0w30 and now I have the noise in the morning.

Patman

I guess some engines will just be noisy no matter what oil you run. Mine is very quiet, not a hint of piston slap at all. I run GC 0w30 (as everyone knows by now)

GuitsBoy

iTrader: (4)

Well, im a believe in the virtues of GC - But now should I find that switching back to M1 5w30 quiets my emgine noise back down to nothing, im suck with an awful decision no car enthusiest should be forced to make. Do I run the oil that takes better care of my car at the expense of god awful embarassingly loud engine knock? Or do I quiet her down and run a lighter oil that may have as much as double the wear metals in any given oil analysis, but atleast she sounds healthy. This is all assuming that switching back to m1 would quiet her back down, which I am not sure will actually happen.

Ryan02SS

iTrader: (3)

If your gonna switch back to Mobil1, why not try their new Extended Performance 5W-30 instead of the regular Mobil 1 5W-30. It has a far superior additive package than regular M1. I don't really have anything to add about the engine noises but it's not from using a thicker oil than 5W-30. Sure a regular 20W-50 in -0 temps would not pump up fast and maybe cause knocking but not a mix of 15W-50 @ 5W-30 Mobil 1.
I run straight 15W-40 in the summer in my LS1 and it's as quiet as back when I used to run M1 5W-30. Latest analysis results are here....... http://theoildrop.server101.com/cgi/...c;f=3;t=002245

LS1_PNYTAMR

iTrader: (1)

i always wait till my guage reached 150+ before moving the car and full temp before being hard on her.. i run mobile 5w30... u said something about ppl giving 5w30 bad reviews? please explain what i missed. i would think with thicker oil its going to be louder at startup when the motor is cool- more piston slap noise, b/c the oil takes longer to circulate to the top of the motor also right?!

GuitsBoy

iTrader: (4)

Many people who frequent bobistheoilguy.com and its respective forums tend to agree that m1 5w30 is on the thin side of what is good for our motors. Often, the oils that are turning back the best oil analysis results are german castrol 0w30, mobil1 0w40, amsoil, and maybe some others.

Does anyone know where i can compare oil viscosity at both 0ºc and 100ºc? Id like to find an oil thats as thin as M1 5w30 at 0º but as thick as 0w40 at 100º. Even though it has a 0w rating, its thicker than the 5w at startup.

Also, how does the new mobil1 5w30 extended life compare to the existing 5w30? I heard it was a little thicker.

fnbrowning

You are going to have to read-n-read, but it is worth your time!
Here is your answer:
http://63.240.161.99/motoroil/index.html

About the author:
Dr. Haas is a physician and surgeon. He graduated from the University of Florida with a degree in biochemistry with honors. He studied motor oils since high school where he did independent studies on this topic. He studied the properties of viscosity.

When he was a general surgery resident in Chapel Hill he studied the flow mechanics of human blood. Today he continues his research by discussion of oil products with chemists in the field and chemists from the oil manufacturers.

He has personal racing experience in Formula Super Vee. He is his own Lamborghini and Ferrari as well as Mercedes mechanic.

Y2K SS

iTrader: (1)

I just did some work on my LS1 and I had some Mobil 1 0-40 laying around from my stroker. WASSUP Patman... you're on this board too huh. I'm S.J.S. for the Ultimate board. Anyway, Patman had me go with the 0-40 on my stroker. I find it quieter in my LS1 and seem to be working fine. Just my 2C.