Just a couple of comments to add. What has happened is the latest oil formulations (SM) have reduced/eliminated a component (zinc/ZDDP) that is harmful to catalytic converters but beneficial to internal engine wear, mostly camshaft/lifter. Since all new cars today use roller lifters, this is not a problem for them. Since our 300's don't have catalytic converters, it is a problem for us. Any diesel rated oil will work fine in the older cars. 15W40 is by far the most common, but straight 30wt. and 10W30 are both available in diesel ratings. Jean-Yves might find it easier to obtain in Canada that Gil in Florida, but it is manufactured. I have frequently seen 10W30 in Shell Rotella in various outlets, but never Castrol. Russ Vaughan lettercars@xxxxxxx wrote: Hi Jean-Yves and All After reading and thinking about all the discussions you mention, I switched to the GTX diesel oil in my 300F for its 1st change after break in. Drove it to the two meets last year. Intend to use the same for its change this year. I would have liked to find a little lower viscosity, as I have plenty of pressure, but lowest I could find in Castrol (brand I have used since my XK-E days of 1964) was the 15-40. 300ly, Gil Cunningham In a message dated 5/2/2007 8:44:41 PM Eastern Daylight Time, jymopar@xxxxxxxxxxxxxxx writes: Hi! I'm just about ready to change the oil in my K and I think there was a discussion a while ago about how modern "energy saving" oil is not so good for our old engines? Maybe it's just engine breaking oil? Anyone with some knowledge about this, feel free to help me chose the right motor oil. Usually I use Castrol GTX 10-40. Maybe synthetic oil would be better? Thanks! Jean-Yves in New Brunswick. ************************************** See what's free at http://www.aol.com. [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/