777Shock777

iTrader: (5)

Hi!

I got a friend who said we should be using 10w30 at all times, except winter of course.
He said that using synthetic 10w30 after 100k miles is better for the motor at that point.

Any suggestions?

LS6427

iTrader: (2)

Your friend couldn't be more wrong. There is no RIGHT oil for LSx engines.

I've always used 20w50 Castrol GTX non-synth.....165,000+ miles and going strong.

Oil is Sooooooooo over thought about in these every day normal LSx engines. Use whatever you want, they all work. I personally decided to use 20w50 because these engines run hot, and that thins oil out, which drops oil pressure. My 427ci has LOVED it for the past 10 years now. Its fine to run in all LSx engines.

If someday you have a specifically built race engine done....then and only then should you use a specific weight/brand of oil that the builder says to use.

Otherwise.......it makes no difference.

.

FiredUpZ28

^Well said/typed/written. I have 130k on mine and I use Mobil 10W40 high mileage. I used to think HM was bullsh!t but it actually helped quiet down all my bottom end noises. May go heavier this summer if it starts making more noise.

RPM WS6

iTrader: (3)

My suggestion is to stop asking this particular friend for his advice on oil.

I always use 0w40 Mobil 1 in my LS1s. One has 16k miles and the other has 102k miles, both run great and don't guzzle oil like some LS1s seem to.

Most LS1s show go wear results with oils on the thick side of a 30 weight or the thin side of a 40 weight.

777Shock777

iTrader: (5)

haha lets put it this way, he drives a ford mufftang.
and he's the kind of kid who comes up to you and says, "well the guys at autozone said this"...

So I was just wondering
I've been running 5W 30 synthetic in mine, but what would be a good oil then for a basically stock motor for the summer? I know the thinner is better for winter when ***** cold.

RPM WS6

iTrader: (3)

It just gets worse. In this case, don't just avoid his advice on oil, avoid his advice on anything car related.

You can run an 0w or 5w even in the summer. There are plenty of us using 0w30, 5w30, 0w40 and 5w40 in the summer. Just about every person on this site has their own opinion about oil, and if you do a search you'll find countless recommendations with good results. If you really want to get serious with it, try several different oils and have the oil tested after each drain interval to see how the engine is wearing and how well the oil is holding up in your specific application.

Karl101

I use Royal Purple 5w-30

LS6427

iTrader: (2)

777,

The point I always try to make on this site is: Every single oil available on the market today, in every single weight, both synth and non-synth........are used in stock, modded and heavily modded LSx engines....

THEY ALL WORK.
It makes no difference. Nobody in 14 years of the LSx engine has someone said, "aw man, my engine blew up because I tried xxxx oil." Now don't use something totally NOT designed for a basic V8 engine.......just use what your manufacturer recommends, or close to it. Thats why they just RECOMMEND it and not require it. It doesn't matter. Even with the Vettes for some years when they said to ONLY use Mobil 1...((marketing deal with Mobil)), people use every make and weight of oil, its the same LSx engine we all have in our F-Bodys, and the engines are all perfectly fine.

I say you should use 20w50, only because after 2 LSx engines it has worked more than beautifully in both. Not to mention the dozens and dozens of other people I know that also use that weight oil in every type of V8 engine you can think of. I like thicker oil because these engines run a bit on the hotter side, so it helps to have a thicker oil to start with.

.

777Shock777

iTrader: (5)

Makes sense. I know right? Gotta avoid them know-it-all Mustang Owners!

How does the measurement of oil work? Where does the xxW xx come from?
I'm fine to try that oil type if you think it should be good in the motor

I just want to know, what does the numbers differentiate mean?

How do you like it?

RPM WS6

iTrader: (3)

There are various places on the web (like bobistheoilguy.com) that have articles that will explain this in great detail (probably more detail than you'd ever want to know). But basically, that first number is the "grade" of the oil as it behaves at cold-start engine temps, and the second number is the grade of the oil as it behaves at full operating temp.

This is why you can use an 0w or 5w even in hot weather, because they will behave like a w30 or w40 (or whatever their second number is) as they heat up, while still giving you the cold start flow of a 0w or 5w oil. Cheaper oils, as they age under use, tend to lose some of their ability to act like a heavier oil when the engine gets hot. I think this is why some people think you need to use a 10w in hotter weather, because the base oil is "heavier" to start with. But this should not be a concern if you're using a good synthetic to begin with.

You want good oil flow at a cold start, as this is when the most wear will typically occur with a street engine. I'm personally not a huge fan of 20w50 oils in stock engines, as their bearing tolerences are not really desiged for such a thick oil on a cold start. This becomes an even bigger issue if the engine is operated in very cold temps (say, near or below freezing). Obviously, LS6427 above has reported good results after 165k miles, but IMO this is not the ideal oil for a stock LS1.

I think you'll find most LS1s (stock short block) liking oils that are on the heavy side of a w30 or the light side of a w40. Some applications may vary, but there are lots of UOAs that show great wear results with oils fitting that description.

87gnx

iTrader: (3)

All oils should should do five things.Cool,clean,cushion,lubricate and protect.After that they wear out. Synthetic, or Dino its up to the person to choose. If you ask twenty people what oil they use (weight and or brand), you'll get at least twenty different answers.The three thousand mile oil change myth netted the big oil companies OVER TWO BILLION dollars in profit in 2008!!!Read and do research to see whats the best for your application.$.02

mjs1012

iTrader: (36)

Before I pulled my stock 98 long lock w/ 226k I used just regular castrol gtx 5w30 with no issues what so ever.

Onyx_Black_Z28

iTrader: (2)

OP, there is a ton of conflicting information in this thread. No disrespect to anyone else that has posted here, but if you really want to understand the difference, please go here as RPM WS6 mentioned:
http://www.bobistheoilguy.com/motor-oil-101/

This is one of those topics where most people have no idea what they are talking about - myself included until I started doing some research on it. Rather than type 15 paragraphs explaining what I feel like is the right answer is and why, I would highly suggest you visit that link. Pay close attention to the differences between regular and synthetic oil and what it means in relation to the numbers you see printed on the bottles. Tons of great information in that article from a guy who is probably smarter than all of us combined - LOL.

arob987

iTrader: (9)

me personally after working for a oil company for a little while oil is oil its just your preference on what you want to buy it all works.just pick if your engine runs best on thicker or thin oil,depending on condition,miles,age.

Karl101

I like it. But I'd have to agree with the above post.

sheaadams86

I use 10w-30 royal purple with 145k on motor, no issues I know of yet but with all these Damn post of different oils and grades I might change it up to see if there's a difference or not

Drivn2Fast

iTrader: (2)

Car is designed for 30 so I'm going to use thirty until the oil pressure can't be maintained. For the first number, I want it to be as thin it can be cold; so I run 0w. To each his own, but the stuff bobistheoilguy talks about, makes sense to me.

ranman02ta

for me I run 5-30 winter months. 10-30 in the warm months.

but here in az it is always warm. except today 49

Onyx_Black_Z28

iTrader: (2)

This is correct. Even 0W-30 is still too "thick" when cold to be optimum for your engine - this is ESPECIALLY true of non synthetic oils. If you read the Bobistheoilguy primers, both synthetic and conventional multi-grade oils (read: any XW-XX oil that you see on today's shelves as opposed to old school straight 30 weight or 40 weight) do not flow well enough to prevent excessive wear on your engine until the engine heats up - to operating temperature of approximately 212 degrees - so as long as you are living on planet earth, this applies no matter where you live.

The optimum choice is a synthetic oil as "thin" as is available for the first number (which is 0W) and then the appropriate grade that creates the right amount of oil pressure at operating temperature. The only true way to know FOR SURE is to actually conduct an analysis of oil pressure at different RPM and temperatures. For those of us that can't/won't go to this level of trouble, the best course of action seems to be to trust GM when they say that a grade XW-30 yields the appropriate viscosity at operating temperature.

Those of you that are using heavier weight multi-grade oil (especially those of you using non-synthetic!), please please please go read the bobistheoilguy primers. Look at what these oils do at given temperatures. Just because your car runs great after 150k miles doesn't mean you aren't putting unnecessary strain on your engine at start-up (and by extension, your battery, starter and alternator).

RPM WS6

iTrader: (3)

There is more to be considered than just the GM recommendation though. Not all w30 oils will be the same, as there is a range of viscosity that can still be called a "30". I'm sure you personally are aware of this, but I'm just pointing it out to people reading this thread. UOAs seem to indicate that LS1s respond well to oils on the thicker side of a w30 or the thinner side of a w40. Speaking in terms of synthetics anyway.

But I do agree (and think this was the intended point of your message) that for those in doubt, or that don't care to do a lot of research and testing of their own, you're usually best off to stick with OEM grade recommendations.