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GM Dexos1 cleaned out the sludge from my 08 Impala SS in 1 year! Stopped the excessive oil consumption and the lifter rattle in 4 cylinder mode. I'm hooked. Used to use Mobil 1 religiously till I noticed almost all of my Mobil 1 customers had noisy lifters in their GM products. Coincidence?
And if I'm not mistaken, Dexos oil is cheaper then Mobil One! Another bonus.
Thats the rub on "oil''....its like everything else auto related youll find different groups of auto enthusiasts who like one over another and swear by it, Ive used what the car came out of the gate with Mobil 1 but lately am curious about trying something else..AHH HAA but which one?...One claims to do this...the other that..? As far as oil consumption in my SS...its near zilch...nada...I am however one of the unfortumate LS owners that got a "piston slapped'' LS motor ,,,bugged the hell out of me for years..until i got LT`s and turn up the radio..viola!! sound inaudible...:lol: Thats said it still pisses me off that GM let those motors roll off the line and then told all of its dealerships to ignore customer conplaints!!! I wonder if a different oil would quiet the slapping?
I have never heard of an oil that will alleviate the start up noise our engines make. It is a combination of short skirt pistons and thermal expansion delay that results in "piston slap".
Ive been told that this isnt harmful to the engine...true? Also its funny how some have it and others dont..Of course NOT funny to us that have them!!!Quote:
Originally Posted by pajeff02
Apparently it isn't too bad for them -- lots of these engines are alive and heading to 200,000 miles these days. That being said, I always allow ours to warm up before putting any load on it.
Piston slap is just one of those operating characteristics of an LS-based engine. Yes, it seems (and is) a little undesirable. But looking at it realistically, there isn't really a possiblity of engine harm from this "knock". The piston skirt is short...yes. But its really well designed and reinforced. So there isn't really much worry about piston skirt collapse. And as time has marched on, its clear that the cylinder isn't getting any damage or wear from the knocking either. These engines are lasting well even with the 10 to 20 second piston knock at cold start up.
Good to hear!! I have 67,000 miles so far and the engine runs strong and hard, Im the original owner and ordered it up in `01, got it with a mere 10 miles on the OD-and have maintained it religiously.So im hoping it will last quite a while plus yes its an LS motor which seems to have admireres attention they know what an LS is capable of for sure!! Thanks-------------
I have noticed much lower engine noise after switching to mobile 0w40
145k miles to boot
Any particular reason for the switch?
That result isn't unheard of considering you went to a thicker 40wt from what I'd guess was a 30wt you used before.Quote:
Originally Posted by Falco78
A while back I also went to a 40wt in the LS engine, from the 30wt I had run for years. Not because I thought the engine needed it, it was more of a decision to get all the cars on the same oil, so I could one....rid my shelf of various makes and viscosities, two...much easier for me to remember what is in each car if I keep them the same :D Sucks getting old.
For the record, mine never has had the piston slap or any other noise, so I noticed no difference when I changed the weight of the oil other than the oil pressure might be a tick higher when it's hot.
Here's a piece of interesting information pulled from a synthetic oil website. Hope you guys that love using their Mobil 1 are at least using the Extended Performance version of that oil. Because apparently Mobil 1 has decided to increase profits by dropping their other synthetics down to a lesser group 3 base stock that doesn't perform as well, especially when you start spreading the viscosity ratings further apart.
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As more and more large oil companies switched their "synthetic" motor oils to the less expensive/more profitable Group III (3) base stocks it has become much easier to identify which are PAO based true synthetic. Of the large oil companies, only Mobil 1 Extended Performance, as of this writing (12-16-2012), is still a PAO based true synthetic. The rest, including regular Mobil 1 and Castrol Edge have switched to the cheaper/more profitable Group III (3) petroleum based "synthetic" motor oil. AMSOIL Synthetic Motor Oils are PAO based true synthetic motor oils with the exception of the short oil drain OE and XL synthetic motor oils sold at some Auto Parts Stores and Quick Oil Change Centers. This leaves more than 20 PAO based true synthetic motor oils manufactured and marketed by AMSOIL with only a few Group III (3) based synthetic motor oils identified by the "OE" and "XL" product name.
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And here is an explaination of what happens to the oil. With the additive package necessary for multi-viscosity, you need to run a group 4 synthetic oil, otherwise you run the risk of shear in high heat conditions, break down, and eventually an oil that no longer resists thinning, the wider the muti-viscosity spread, the worse the conditions because it has more of those viscosity additives in it. Interesting stuff....
Drawbacks of Viscosity Improving additives
Multi-grade motor oils perform a great service not being too thick at cold startup to prevent engine wear by providing more instantaneous oil flow to critical engine parts. However, there is a draw back. These additives shear back in high heat or during high shear force operation and break down causing some sludging. What's worse is once the additive begins to be depleted the motor oil no long resists thinning so now you have a thinner motor oil at 210 degrees. Your 10W-30 motor oil can easily become a 10W-20 or even a SAE 10 (10W-10) motor oil. I don't have to tell you why that is bad. The more VI additives the worse the problem which is why auto manufacturers decided to steer car owners away from motor oils loaded with VI additives like the 10W-40 and 20W-50 viscosities.
The less change a motor oil has from high to low temperatures gives it a high Viscosity Index. Synthetic motor oils that are made from Group IV (4) PAO base stocks have Viscosity Indexes of more than 150 because they are manufactured to be a lubricant and don't have the paraffin that causes the thickening as they cool. But petroleum based motor oils (Group I (1) & II (2)) usually have Viscosity Indexes of less than 140 because they tend to thicken more at the colder temperature due to the paraffin despite the addition of Viscosity Improving additives. The higher the Viscosity Index number the less thinning and thickening the motor oil has. In other words, high number good, low number bad. Low numbers thicken more as they cool and thin more hot. You see these Viscosity Index ratings posted on data sheets of motor oils provided by the manufacturer.
As already mentioned, VI improving additives can shear back under pressure and high heat conditions leaving the motor oil unable to protect the engine properly under high heat conditions and cause sludging. Also there is a limit to how much viscosity improving additives can be added without affecting the rest of the motor oil's chemistry. Auto manufacturers have moved away from some motor oils that require a lot of viscosity improving additives, like the 10W-40 and 20W-50 motor oils, to blends that require less viscosity additives like the 5W-20, 5W-30 and 10W-30 motor oils. Because stress loads on multi viscosity motor oils can also cause thinning many racers choose to use a straight weight petroleum racing motor oil or a PAO based Synthetic which do not have the VI additives. But only the Group IV (4) PAO based synthetics generally don't need VI additives. Read on to learn why:
Thanks for the article it is definitely something I will consider on next oil change
Any word on the recent changes to Penzoil Platinum?
I've been trying to do some digging and so far that's all I've found. Oil companies seem to be elusive about their changes, especially when it's for the worse or their own profit gain.
However that first statement I posted, second sentence, spooked me. It's basically saying all synthetics have switched to a lesser group 3 base stock including all Mobil 1 (accept extended performance) which has always been in high regard for many years. The only true group 4 synthetics left that don't need all those additives to make multiviscosity work, according to that statement as of 2012, is Amsoil (with acception to OE and XL lines) and the Mobil 1 Extended Performance.
The OE and XL lines of Amsoil synthetic are of course cheaper (about $6 a QT) but they are recommended for short oil change intervals. Which explains that link perfectly, since a group 3 oil which has all those parrafins and other additives to make those multi-viscosities work also break down sooner.
I'm sure the Mobil 1 Extended Performance is also more expensive than the regular Mobil 1. I'd also bet that's how Mobil 1 gave it the name "extended performance" because it's a group 4 base stock that doesn't use the same additive package in multi-viscosity that causes the early break down of the group 3 stuff, hence it's capable of longer oil change intervals.
Since I was already running Amsoil high zinc stuff in my classic cars, and also made the switch to Amsoil in my Duramax, I figured it was time to put the LS engines on it as well and give them the same treatment. To keep my amsoil stock the same brand of high zinc stuff on my shelf, I went with their 10w-40 as that is the thinnest they have in the high zinc premium protection line that I like to use. I also figured since I live in the hot desert the 40 WT was a good idea over the 30 that I was using. Ironically the 10W Amsoil has a lower cold pour rating than any of the other 10W's on the market so I also improved the cold startup as well at the same time.
If it makes you feel better Jeff, Pennzoil Platinum was always a good group 4 base stock in the past, and I used it in my LS engines for years right up until recently. Now with that statement I found that I posted above, I'm not so sure anymore. Since I was already using Amsoil in some other stuff it made my decision easier, so I just simply made the switch.
I was thinking of using Valvoline VR1 I wonder if their synthetic version has changed the base stock to as you stated FBJ? I have been trying to decide between it and Amsoil Dominator Racing Oil.
I can't be sure but I would take that statement I posted above as a yes, most likely. Again, I think these oil companies are being elusive and this isn't the kind of information they want out in the public. However I'm not the best internet surfer, maybe others with more computer skill would have more luck?? Sarge was always good at digging this stuff up...Quote:
Originally Posted by 98TransAmWs-6
I used Valvoline VR1 conventional for years in some classics, and sometimes the synthetic. Matter of fact still have my old truck full of conventional VR1 because it's what Scoggin/Dickey recommended I break that GM crate motor in with a couple years ago. Haven't really driven it much at all so it's not due for it's next change for quite a while. But I had planned to swap that over to Amsoil when I do. Right now it's doing alot of sitting so not concerned with it at the moment.
Honestly I don't think you can do any better than the Amsoil line of the Dominator oil, Premuim Protection, or the Z-rod stuff. But if you're looking to save a few bucks it wouldn't bother me to use the VR1, I'd just probably shorten up my oil change intervals. Best way to tell how things are doing would be a couple of oil annalys with each oil and compare, might be interesting.
The car only gets driven maybe 1000 miles a year so I guess it wouldn't really matter between the two. My engine builder suggested vr1 but they said there is nothing wrong with amsoil either. I was also looking at the racing version of vr1 as well. I think I may do conventional vr1 racing oil for break in and amsoil dominator after that.
With only 1,000 miles a year, with probably oil changes every season, I likely wouldn't worry too much what oil is used. The VR1 would work fine. Definately conventional for break in, and then what ever synthetic you choose after that. You could always do an oil annalys once in a while and see what things look like with either oil. Maybe one sample after a season of VR1 and the following year do one with Amsoil and see if things are any different. That would be a solid way of knowing which oil is working well enough.Quote:
Originally Posted by 98TransAmWs-6
Jeff...that's also what I would do with your Pennzoil if you're thinking of changing. I know you keep good care of the car and it's seldom driven. I'm betting the Pennzoil is probably serving you just fine. An oil annalys would tell. Might be worth the trouble before spending more money on different oil.
Like I said, I changed from the Pennzoil in the LS engines only because I was already using high zinc Amsoil in the other older cars which out number anything new that I have. I couldn't seen keeping Pennzoil on the shelf just for 2 cars and Amsoil for 10 others. So I consolidated, and didn't do any oil annalys with the Pennzoil before I switched. I'm sure the Pennzoil was doing just fine, I have no complaints. Just easier for me to use one oil.