BLKWS.6

I forgot, but someone at some time did a study (Patman probably) and determined that the LS1 likes XX.XX CST @ 100*C thickness of oil. I am currently running Syntec 10-30 and its rated at 10.1 and I have a tiny bit of valvetrain noise. I did not know it was only 10.1 CST @ 100*C though. I am looking into 10w40 Syntec which is 13.2 CST@100*C. What is the weight that LS1's prefer and any advice on which oil in that weight?

slt200mph

iTrader: (42)

Mine likes 0-40 Mobil One

89tang

iTrader: (15)

Mobile 0-40 here also

The guys at the parts stores always ask me when they see the weight "damn what are you putting this in a race car" no that TA out there .

BLKWS.6

Cool, what "formula" is it, is it a group 4/5 oil or group 3 oil? Also, what is it called "extended 15K formula" "7500" "5000" "Mobile 1 clean" what?

89tang

iTrader: (15)

It's called mobile 1 0w-40 it's no extended formula or none of that crap. I can only find it at our local autozone nowhere else has it around here.

BLKWS.6

Cool, I will check it out. It's either that or 10-40 syntec. I would like the 0-40M1.

Patman

My C5 definitely seems to like GC 0w30, which checks in at 12.2 cst at 100c. So it's my belief that a basically stock LS1 likes an oil which is a thicker 30wt, to a lower 40wt. I wouldn't choose an oil thicker than about 14 cst unless you're doing a lot of road racing and/or see oil temps above 250F on a regular basis.

If you're just driving around town, and don't really push the car too hard, you can go lower than 12.2 cst with great results as well.

The best way to determine if you've chosen the right oil and viscosity is to do regular oil analysis. This way you can see how the engine is wearing and make adjustments accordingly. Also keep in mind that driving habits and an engine's state of tune play a huge factor in how your engine wears also. So if you get a bad oil analysis report you don't necessarily have to switch oils right away, but look at other areas that may need adjusting first. That's why I send all my reports to Terry Dyson for his expert interpretation, as he will suggest mechanical improvements which will improve the reports (such as on my wife's Honda he recently suggested to change the plugs/wires/cap/rotor in order to improve it's oil analysis results in the future)

BLKWS.6

I have 70K miles on stock plugs/wires. I am debating on when to tackle that one. I just ran Chem12 through the gas tank. I am thinking 10-40Castrol Syntec as its CST @ 100*C is 13.2, kinda a happy medium btwn. 0-30GC and 0-40 M1.

Patman

I would definitely do the plugs at this point in time, but your wires are probably fine.

Syntec 10w40 should work out well in your car. I would definitely choose it over M1 0w40.

slt200mph

iTrader: (42)

I never see the Syntec 10-40 around here..I am sure it is out there but have seen no reson to spend a lot of time looking for it..the M1 0-40 has been good for me and my engine ..124,000 miles with no oil consumption...I change it every 5000 miles ... it seems like it is doing the job very well..

BlackHawk T/A

iTrader: (3)

Amsoil 5w40 may be worth looking into also. It is their "euro formula". Not cheap, but very very good stuff.

BLKWS.6

Im going with Patman, 10-40 over 0-40.

BlackHawk T/A

iTrader: (3)

Keep in mind weight varies from brand to brand...

o2man98

This is true. Each "weight" has a specific range to fit into. See the chart below.

Ryan02SS

iTrader: (3)

I've done 8 UOA's on mine and it showed the lowest bearing and iron wear with a 40W oil over the 3 UOA's with 10W-30's. I've been running Shell Rotella 5W-40 Synthetic.