But the Saab 93 which has an Ecotec engine in it is factory-filled with 0W30.
GM Viscosity Requirement
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Reading this may help clear things up:
http://theoildrop.server101.com/forums/s...ge=0#Post258506
Some 0W-30 oils are thicker than most 5W-30 at operating temperature.
I use Castrol 0W-30 in my Enzo. It calls for the Shell Helix Ultra 10W-60.
aehaas
http://theoildrop.server101.com/forums/s...ge=0#Post258506
Some 0W-30 oils are thicker than most 5W-30 at operating temperature.
I use Castrol 0W-30 in my Enzo. It calls for the Shell Helix Ultra 10W-60.
aehaas
Nice pic Doc, what a lovely car
. Do you have oil consumption on the Enzo when you give it stick?
A top tier, 0w-30 synthetic like the Amsoil Series 2000 or the German Castrol can be used as a direct replacement for 5w-30 and 10w-30 oils, as well as for 0w-40/5w-40 in most European engines. This is based on twelve years of experience with the SAE 0w-30 grade in a multitude of applications in hot climates, including a hard driven, 1.8L/225 Hp, Audi TT roadster.
I not up on the current Castrol specs, but the Amsoil 0w-30 has a VI of 187, a viscosity @ 40C/100C of approx 54.0/10.5 Cst and pumps better than any 5w-30 I've come across....
I not up on the current Castrol specs, but the Amsoil 0w-30 has a VI of 187, a viscosity @ 40C/100C of approx 54.0/10.5 Cst and pumps better than any 5w-30 I've come across....
KBFXDLI wrote: "I have spoke with 2 GM piston design engineers who believe that the film from less than 5w30 is insufficient at start up for their design criteria. Both of these guys have MS degrees and over 20 years experience in engine design. I believe them."
So what is one to do when their beliefs conflict with rationality?
GCgreen in a 2005 GM 3.5L V6. Specs 5W30.
So what is one to do when their beliefs conflict with rationality?
GCgreen in a 2005 GM 3.5L V6. Specs 5W30.
Counterpoint.
I wonder what requirements constitute start-up design criteria for GM engines. From my experience, I’d say “free of piston slap” isn’t on the list. Any chance of asking them what can be done to eliminate that design problem? I’ve tried several different oils, as well as Seafoam, but the 3.4L in my van sounds like a diesel the first few minutes after a cold start.
Dave,
It’s way past “tomorrow”. Have you found the page number in my manual where GM says 10W30 is OK in my ’06 Sierra? There are folks here with stale popcorn waitin’ on the answer.
"I have spoke with 2 GM piston design engineers who believe that the film from less than 5w30 is insufficient at start up for their design criteria. Both of these guys have MS degrees and over 20 years experience in engine design. I believe them."
An XW-30 wt. oil has a Operating Temperature Viscosity of 11 cS, a 40 wt. oil = 14 cS, a 50 wt. oil = 18 cS. How can even a 0W-20 wt. oil that has a start up viscosity of 100 cS at 75 F be too thin? Viscosity is viscosity. The film thickness of an oil with a viscosity of 100 cS is considerably thicker then the film thickness of an oil with a viscosity of 11 cS. Viscosity is wholly temperature dependent. A straight 2 wt. oil with a viscosity of 50 at 75 F is still too thick at start up.
You may have missed what the engineers have said or they know nothing about oil (unlikely).
aehaas
An XW-30 wt. oil has a Operating Temperature Viscosity of 11 cS, a 40 wt. oil = 14 cS, a 50 wt. oil = 18 cS. How can even a 0W-20 wt. oil that has a start up viscosity of 100 cS at 75 F be too thin? Viscosity is viscosity. The film thickness of an oil with a viscosity of 100 cS is considerably thicker then the film thickness of an oil with a viscosity of 11 cS. Viscosity is wholly temperature dependent. A straight 2 wt. oil with a viscosity of 50 at 75 F is still too thick at start up.
You may have missed what the engineers have said or they know nothing about oil (unlikely).
aehaas
Patman
Staff member
GC 0w30 has a 100c viscosity of around 12.2 cst, and it's 40c viscosity is around 68-69. So it's quite a bit thicker on a normal cold start than most other xw30 oils out there.
Im not sure the information you got from those piston engineers is correct, since Mobil 1 0W-40 is Opel Approved, Opel is owner by GM...spot the problem...odd thing is that most of the pistons in Opels are Mahle, so I'll bet those guys didn't do much designing there, more specing.
Anyway, I'd take what they said (if correctly quoted) with a pinch of salt since its clear they don't understand how oil works. You can use Castrol SLX Longtec 0w-30 AKA GC with confidence...SAAB and Opel owners here and in the UK do it all the time with no hassle.
"GM piston slap" is really a manufacturing quality control problem rather than a design problem. You can bet your sweet bippy that they don't design in piston slap or any other noise on purpose.
Further, we have no idea what those GM engineers said or meant. We have some guy who believes he understood what he thought they said, but, it could be the case that what he heard is not what they meant or was taken completely out of context.
I am, and will continue to run, GC 0w30 in my new Envoy. The manual says the same dribble as mentioned above, 5w30 recommended, 10w30 OK above 0F, and 0w30 for extreme cold temps. The idea that if I have 0w30 in the engine, and a heat wave brings ambient temp up to, say, the 0F mentioned, that I would have to go out and change the oil to 5w30 to avoid piston damage is ridiculous beyond belief. I believe the Envoy engine is an Isusu. This Japanese engine, in an American SUV, likes German oil, and it will stay that way.
Do these GM pistons need more help because of poor design and piston slap in many engines. GM has been building engines for a long time and one has to wonder why the piston slap. They know better.
According to this Lube Report Article , (probably the best reference to GM 6094 that I've run across), the GM 6094M low temperature pumping spec dates back to at least 1990.
BINGO we have a winner! Yes the slappers do need more film because of a compromised design geometry. Now the GM guys are so paranoid about a repeat that they won't spec a 0w oil no matter what you say. But, I did have an 02 5.3L slapper and they were correct that a 10w30 or 10w40 pennzoil dino did leave enough film to quiet the slap as long as the engine had not sat for more than 4 or more days.
I'll echo that comment, as my 99 Silverado developed pistonslap at cold start-up, and a Hi-Mileage 10W-30 or a 10W-40 would certainly reduce the noise level. Oil film thickness is certainly a factor.
BTW, a good technical expalnation at http://www.pistonslap.com/whatisit.htm .
Especially in the 5.3L & 6.0L V8's, piston slap is both a problem of production tolerances & piston design, with the higher ring position and shorter piston skirts.
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