Best oil for 2004 Corvette with mild piston slap?

[Dave_in_RI]

What's one of the best oils for my stock 2004 Corvette? GM says use Mobil 1, 5W-30. I was thinking of using Royal Purple instead.

My LS1 engine has some mild piston slap at cold startup, so I'd like to use something that might help to moderate the slap (or any damage being caused). I realize the slap noise is caused by forged alum pistons being slightly too small for the engine bore, and is common to many high performance engines. Noise goes away when warm.

Thanks for tips

 

[Throckmorton]

Just out of curiosity, what does piston slap sound like?

 

[OVERKILL]

Originally Posted By: Dave_in_RI
What's one of the best oils for my stock 2004 Corvette? GM says use Mobil 1, 5W-30. I was thinking of using Royal Purple instead.

My LS1 engine has some mild piston slap at cold startup, so I'd like to use something that might help to moderate the slap (or any damage being caused). I realize the slap noise is caused by forged alum pistons being slightly too small for the engine bore, and is common to many high performance engines. Noise goes away when warm.

Thanks for tips


I don't believe your engine has forged pistons. They are Hypereutectic, which is a silicon-impregnated aluminum alloy.

Nothing wrong with the M1 5w30. You might try the 0w40 and see if it alleviates some of the noise.

 

[aquariuscsm]

M1 seemd to make my engine a bit "noisier" and sluggish. I`d definitely give the RP a try and see how your Vette likes it.

 

[mpersell]

Depending on mileage on the motor maybe look for a 10w-30 if the slap is cold engine noise or a 5w-40 or 0w-40 if its noisier when its hot.

Schaeffer 7000 or 9000 would be a good candidate for some dampening with their EP additives.

 

[jorton]

" I was thinking of using Royal Purple instead. "

Is it synthetic? In other piston slap threads members said synthetic reduced, and even eliminated piston slap noise.

 

[Patman]

You might want to give Syntec 0w30 a try, my 98 Corvette's engine sounded a bit quieter when I ran that oil.

 

[buster]

pickled said SSO made his C6 very quiet.

 

[mechtech2]

It will be tough to get an appropriate oil that will make the basic construction/design of the engine to be perfect in all conditions.
Those piston skirts are temperature sensitive, and there's not much we can really do about it.

 

[zulu]

My Silverado 5.3 has a bit of slap on cold mornings too. Never totally resolved on ANY oil, but GC 0W-30 and Amsoil ASL 5w-30 (never tried SSO) made it the least noticible. It's loudest on Mobil 1.

 

[Dave_in_RI]

I stand corrected - my Corvette LS1 has "Hypereutectic" pistons. The slap is annoying, but my Chevy truck has done it for years with no apparent ill effects. Synthetic oil in my truck REALLY helps though.

I'm hoping to find something that will make a noticeable difference in my Corvette.

-

 

[cfromc]

Amsoil HDD 5W-30 may quiet it down slightly. Look for oils that are a little thicker @40C as there seems to be a correlation. Just keep in mind the specs listed for oils are the specs when they are new. As they are used the viscosity changes as does the additive levels. I tried M1 HM 10W-30 and it quieted it down real nice for a short while then the noise returned. After two poor UOA's I will never use that oil again - but, for a short while the piston slap was reduced.