emj2006

iTrader: (5)

I have been running my car with 10w-30 oil and I want to change it with 5W030 oil. Will there be any problems or things I should consider? Thanks.

iamsickofitall

iTrader: (18)

you might see some more oil getting sucked through the PCV than with the thicker oil but that's nothing to be overly concerned with unless it's a huge amount

staringback05

iTrader: (8)

umm unless u change from 30 to 40 u probably wont see any difference

Mike02Z

iTrader: (13)

A lot depends on the oil. Switch from M1 10W-30 to M1 5W-30 you will probably see no difference. Switch from Amsoil 10W-30 to M1 5W-30 and you probably will as Amsoil 10W-30 is thicker at temperature than M1 5W-30 at temperature. Switch from M1 10W-30 to GC 0W-30 and the M1 is still thinner. The 0W/5W/10W designation really only matters when the engine is cold and in colder climates. The LS1 likes a minimum real 30-40 weight oil at temperature.

ls1wfo

That's strange seeing as how GM recommends 5w30 weight. just where did you get your info? Street driven down south M1 does just fine . Less wear at start-up, better gas mileage. I run my 02 Z convert. hard every day & it has never used a drop of oil that I can measure on the stick. 40,000 hard miles, but I do let it warm up to temperature before I even pull it out of the garage, mainly because I can't stand to listen to that damn piston slap. Fantastic oil pressure all the time. High volume oil pumps are not needed either.

Mike02Z

iTrader: (13)

My information comes from oil tests I have had done but mostly from the oil guru here Patman and his crew that put together the oil related site bobistheoilguy.com. Now I would respectfully ask where you get your information that M1 causes less wear at start-up? I certainly hope it's not from listening to what M1 says. That is hardly impartial.

I stand by the claim that M1 5W-30 is not ideal for the LS1 as it is closer to a 20 weight oil at temperature. This is not my opinion but backed up by oil tests. I'm hoping Patman can chime in here....I also suggest looking at the tests over at bobistheoilguy.com. Nothing wrong with M1 5W-30 I've used it for years in my other cars but will NEVER use it in an LS1 again.

Patman

It's true, the LS1 engine definitely prefers an oil which is between 12-14cst at 100c, which means it likes an oil that is at least on the high end of the 30wt range up to the middle end of the 40wt range. Oil analysis results have proven this.

chevygirl

iTrader: (69)

What do you mean by the high end of the 30wt? Is that 10W-30 or do you mean certain brands are different? I was told to not use 40wt in this car. This can be confusing. The guy I bought the car from said he thought he had used 10W-40 but I went with what the book said and did M1 10W-30 and now I have that piston slap. I am new to the LS1 and I want to get it right.

Mike02Z

iTrader: (13)

What is meant by the high end of of the 30wt is that when at normal operating temperature the LS1 likes an oil that is between a true 30 weight and 40 weight. M1 5W-30 is really closer to a 20 weight oil at temperature. It tends to thin out too much in the LS1.

Oil will not cause piston slap but can make the engine noisier. Mine would sound like a sewing machine when I first ran M1 5W-30. If you can find the German Castrol 0W-30 that is an ideal oil for the LS1. It MUST say "Made in Germany" on the back. If not Redline 5W-30 or Amsoil 5W-30 are good choices. If you want something a little more reasonable in cost the M1 Truck/SUV oil is suppose to be good.

As far as using a 10W-40....I would not use this if you operate your LS1 in VERY cold climates. The first number (5W or 10W) is the oil weight at startup and if you run your car in the winter I would stick to a 5W-xx or even a 0W-xx oil. If you don't run your car when it is very cold a 10W-40 should be fine. If you live in the desert a 10W-40 is preferred to a 5W-30.

chevygirl

iTrader: (69)

I live in memphis tn and it is really hot here in the summer but in the winter it is usually above freezing. Why is the 0W- 30W german castrol different from Mobile 1? I didn't buy this car to race but I want it to perform well and mainly not cost me alot of money in the shop. In the summer would a 5W or 10W be better? Is the GC synthetic?
I think the guy I bought the car from used Syntec 10W-40. It sure was quiet whatever he used. The noise is just annoying to me and worries me a bit.

Mike02Z

iTrader: (13)

Best bet is to head over to bobistheoilguy.com and read up on the GC 0W-30. You can also search here as there are a number of threads that discuss why it is better. It boils down to the base synthetic that is used for GC is very exotic and has amazing protection and wear properties. I'm not the best person to get into the technical side of the oil but Patman has run this oil for over 9k miles in one of his cars and the oil test came back that the oil still had more life to it which is pretty amazing. On my last test the GC was in over a year and my oil test came back that there was virtually no engine wear and that I could have gone MUCH longer on that oil. I now only plan to change it once every 2 years but I don't put many miles on my car either. Under 5k per year.

chevygirl

iTrader: (69)

How does 10W-30 Castrol Syn compare to 10W-30 Mobil 1? Is it thicker?