When is the best time and how do I go about switching to synthetic motor oil for my 05 CTD?

Thanks for your help.

05 CTD, 4.10 SRW 6spd, all stock, tow 33fkt HR Presidential 5er.

 

it all depends on how you drive it to break in the engine. if you run it hard, you could have that engine broken in before your 1st oil change time by the book. if you putter around and drive it gently, it can take you the 20,000 some here talk about having on the engine before it is broken in. proper break in doesn't take long if you drive it to break in the engine. driving like that though is hard on the rest of the drivetrain which needs to be broken in differently than an engine. on an engine dyno, you can have the engine broken in very well in less than 45 minutes.
driving it around in town making sure you do lots of sharp turns left/right for a few 100 miles, then load that engine as hard as you can through the torque rise [1600-±2800rpm] for a few hours and you will have a transmission and differentials and engine broken in well to accept synthetic..

on my truck, my first oil change was at a little over 3,000km [±1900miles] and i put 10w30 in it for winter, then spring at 6,000km [±3,750miles] i put 15w40 in it, then fall at 10,000km [±6,200miles] i put 5w40 syn. in it and it has had synthetic in it since [now with 0w40 in the sump].. to me knowing how i broke the engine in, it was not too early to switch to synthetics.
some will say that is way too early. some also are scared to run anything but 15w40.. and as the saying goes, opinions are like butt holes, everyones got them and you fill in the rest.

 

Thanks for the knowledgable input. I wonder what oil is in the engine from the factory. I know they are Valvoline Blue fans but have not been able to find out what they use in new engines.

Thanks again, have a great weekend,

Charles

 

i think you got that right on the money there... it has been discussed here before and apparently that is what the factory fill is...