I found this interesting info on the Blackstone labs web site:
Which Viscosity to Use? Engine owners often stray from manufacturers' recommendations regarding viscosity of oils. The engine builders dyno-test their engines using a specific viscosity oil, so when you use the viscosity they recommend, you are working with a known result. Going to another viscosity is an experiment, but it's usually a harmless one. For the sake of efficiency you want to run the lightest grade oil in your engine possible, within limits. We are seeing that trend for newer engines, for which the recommended grade is getting progressively lighter. The common 10W/30 has become a 5W/30, and some manufacturers even recommend 5W/20 oil. On the other hand, we can't see (in oil analysis) where it hurts anything to run heavier 10W/30s or even 10W/40s in modern automotive engines. The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase. The trick is to find the right viscosity for your particular engine, which is why we suggest following the manufacturer's recommendation.
Blackstone states that viscosity is not just the resistance/thickness of the oil, but the thickness of oil at a certain temperature and the standard temp.used to measure is @210F. Yesterday our temp down here hit 95F and my oil temp was reading 228, makes me wonder what I'll be seeing when summer hits hard and we have 100F+ days. If you read their analysis, Dodge is really running thinner oil to help fuel economy probably to make the CAFE/EPA green weenies happy.
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I found this interesting info on the Blackstone labs web site:
Which Viscosity to Use? Engine owners often stray from manufacturers' recommendations regarding viscosity of oils. The engine builders dyno-test their engines using a specific viscosity oil, so when you use the viscosity they recommend, you are working with a known result. Going to another viscosity is an experiment, but it's usually a harmless one. For the sake of efficiency you want to run the lightest grade oil in your engine possible, within limits. We are seeing that trend for newer engines, for which the recommended grade is getting progressively lighter. The common 10W/30 has become a 5W/30, and some manufacturers even recommend 5W/20 oil. On the other hand, we can't see (in oil analysis) where it hurts anything to run heavier 10W/30s or even 10W/40s in modern automotive engines. The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase. The trick is to find the right viscosity for your particular engine, which is why we suggest following the manufacturer's recommendation.
Blackstone states that viscosity is not just the resistance/thickness of the oil, but the thickness of oil at a certain temperature and the standard temp.used to measure is @210F. Yesterday our temp down here hit 95F and my oil temp was reading 228, makes me wonder what I'll be seeing when summer hits hard and we have 100F+ days. If you read their analysis, Dodge is really running thinner oil to help fuel economy probably to make the CAFE/EPA green weenies happy.
That is a huge reason why dodge has gone to the thinner oils. They are producing a high quality engine that doesn't have huge tolerances that require thicker oils to creates large film thicknesses in order to protect the engine. Also as to the MDS and VCT (VVT) the engine WILL NOT run right on thicker oil viscosities. My neighbor is a certified dodge mechanic and now that the '09s have been out a while he is seeing more people come in complaining of the engine running like crap. First thing he asks is if they did an oil change and what viscosity did they use. Everytime they used a heavier oil thinkin they know better than the manufacturer. As soon as they replaced the oil with the 5W-20 everything was fine again. He has said that to date this is the only issue he has seen with the new HEMI engine (no one has brought one in and actually had something wrong with it.)
This engine is extremely picky about the oil visocosity. The VCT (or VVT depening on your engine) as well as the MDS mechanisms only funciton properly with 5W-20. Using a heavier viscosity WILL cause your engine to perform poorly. Furthermore, heavier viscosities do not necessarily perform better in higher temps in newer engines that are machined to higher specs. In fact the higher viscosity in newer engines will decrease performance as the tighter tolerances make it harder for a more viscous fluid to penetrate between the wear surfaces where lubrication is needed.
MDS is a pure electronic thing and not dependent on the oil viscosity...... IMHO...... viscosity has nothing to do with the electronic of the engine.......
Oil grades and use. If you have the MDS system, be sure to use 5W20 oil - note that many dealers will use bulk 10W30 or even 10W40, partly out of ignorance and partly because it’s cheaper. You need to use the right oil if you want to keep your engine. Of course if the owner’s manual says something else, follow its advice - but don’t be convinced by a mechanic or oil-change place. Insist on the right grade and if they don’t use it...get a refund and go somewhere else. A technical service bulletin (TSB) - 09-015-04 and 09-013-04 - says: “Vehicles with the Multiple Displacement System must use SAE 5W-20 oil. Failure to do so may result in improper operation of the MDS.” Watch the mechanic pour it in! (This is said to be the real reason BMW provides free oil changes.)
The MDS IS affected by the oil viscosity. I don't know the exact reason for it yet but I have my theories and need to research the exact mechanism of the MDS.
well I used Amsoil 0W-30 in my 06 HEMI and averaged 19 MPG with 59800 miles on it and had no effect on the MDS..... I currently use Amsoil 0W-20 in my 09CC Hemi and the MDS functions as advertised and am averageing 18 MPG with 6700+ miles on it..... The MDS kicks in as advertised up to 72 MPH........
MDS is a pure electronic thing and not dependent on the oil viscosity...... IMHO...... viscosity has nothing to do with the electronic of the engine.......
MDS is not a purely electronic thing. The engine still has to switch from 8 cylinders to 4 cylinders and then back to 8 cylinders with ease. If the viscosity is not right, it will not happen. The Hemi needs very little resistance to switch into 4 cylinder mode. If you run a 10w30 or 20w40, it won't go into 4 cylinder mode as it should and it may very well throw a code.
I would use niether...... I would use Amsoil and Amsoil filter....... used the stuff for 25 years.... the best stuff money can buy
Quote:
Originally Posted by crew7809
well I used Amsoil 0W-30 in my 06 HEMI and averaged 19 MPG with 59800 miles on it and had no effect on the MDS..... I currently use Amsoil 0W-20 in my 09CC Hemi and the MDS functions as advertised and am averageing 18 MPG with 6700+ miles on it..... The MDS kicks in as advertised up to 72 MPH........
For those of you running AMSOIL, you need to be aware of what that brand of oil will do over time.
I am having a hard time finding the link that proves what I am about to say, and if I find it I will post it.
For people that run amsoil in their vehicle for extended periods of time, the oil will slowly change to a higher viscosity.
The lab report that I read showed at a starting weight of 5W20.
at the end of 24,000 miles (I think) the oil viscosity was rated at 15W40.
This is bad news for those of you running the Hemi with its VVT or VCT MDS.
I hope Hammer sees this post, because I know he has the link for it....
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Oil grades and use. If you have the MDS system, be sure to use 5W20 oil - note that many dealers will use bulk 10W30 or even 10W40, partly out of ignorance and partly because it’s cheaper. You need to use the right oil if you want to keep your engine. Of course if the owner’s manual says something else, follow its advice - but don’t be convinced by a mechanic or oil-change place. Insist on the right grade and if they don’t use it...get a refund and go somewhere else. A technical service bulletin (TSB) - 09-015-04 and 09-013-04 - says: “Vehicles with the Multiple Displacement System must use SAE 5W-20 oil. Failure to do so may result in improper operation of the MDS.” Watch the mechanic pour it in! (This is said to be the real reason BMW provides free oil changes.)
