I asked my dealer for synthetic oil for my next oil change and he suggested a 5w-40 grade oil. isn't this a bit thick? What do you think?

 

I think 5-W40 geared towards diesel engines.

 

let me get this straight your dealer recommend you go to 5w40?

lol I say let them put it in writing and do it? but if you dont want to wreak your motor you will stick to the manufacturer rated oil 5w20. Then give your dealer tech a runnin closeline

 

Yeah seeing as you live in Canada too, I would stick to 5w-20. 5w-40 might be a bit too thick for our winters.

 

there was a good one liner quote from somewhere about thicker oil, not sure where it came from , i think it was nordicgroup.us but anyways goes something like
"Thicker is Better Myth
The reason that oil viscosities have gotten thinner is because bearing clearances have become smaller. Using thicker oils will interfere with oil flow and the oil pressure will increase. In a worn engine it may be okay to increase the viscosity of the oil because the bearing clearances have become larger.
"