Thunderstick wrote:
What was further interesting was that Castrol would not recommend using their 5w-40 because it was not tested and approved to that Chrysler spec. even though it met SM/CF and ACEA A3/B4. Of course whenever this engine is used elsewhere in Europe in other applications the Chrysler spec would not be used at all. Is it possible that a part extraneous to the engine such as the Garret turbo benefits from a Euro spec oil more than an HDEO spec oil?
"Of course whenever this engine is used elsewhere in Europe in other applications the Chrysler spec would not be used at all."
Not so sure about that, but maybe so. I agree that the MS-10725 spec is an enigma. When a VM engine is used in any application, VM Engineering should most certainly be involved. I do have an idea as to how to find it; I won't share my thoughts on that one... I'll just see if I can source it through some people I know.
"Is it possible that a part extraneous to the engine such as the Garret turbo benefits from a Euro spec oil more than an HDEO spec oil?"
That is doubtful based on the information that I do have about the Garrett turbo on our CRD. What information I have refers to normal operation oil pressure variance and oil temperature levels. IIRC, the viscosity and volume of oil is something that Garrett defers to the engine manufacturer. Keep in mind, while significant, they are but one component on an engine. They may offer suggestions on oil, but my thought is the ultimate decision is up to the manufacturer, taking into account the various factors in their decision making process about such things, i.e. warranty, cost, desired change intervals, marketing, etc.
As to which oil I use, please refer to my signature; I have had great service from it. It used to have the MS 10725 designation until marketing recently changed at Amsoil. Still, the long list of MFG specs that it does meet is quite long. Hope this helps.