I run 15w40, its gonna get cold in few month, so when is it too cold to run such oil weight?

 

bump

 

Well considering that I'm running cold cell testing with 15W-40 oil this week, I can give some input.
15W-40 oil really becomes a bear to flow when your at 10 degrees F and may cause oil pickup issues when starting. The owners manuals probably recommend thinner oils proir to reaching 10 degrees though.

Are you running 15W-40 CH/CI diesel oil? If you are wanting to stick to CH/CI oils for the detergents in them or for the higher weight at operating temp.....Shell makes a 0W-40 systhetic CH/CI oil and Delvo makes a 5W-40 synthetic CH/CI oil. Look at a diesel truck dealership or AutoZone, etc

Where are you located?

 

i'm running penzoil 15w40. temps are in 50-70's right now, but soon will start dropping to 40' and so on to freezing temps. 15w40 is fine for right now, but i'm not sure on when to stop using it.

 

look for shell rotella synthetic 5w-40. best deal for synthetic oil on the market. costs about $13/gallon at wallmart. problem is that you'll have to buy another gallon to bring up your oil capacity to 4.2 quarts.

15w motor oils satisfy the cold pumping requirements at -20C.

 

i was thinking of using that shell motor oil from wallmart..

so while 15w40 meets requirments for -20c, doesn't mean it will be optimal for lets say 0-10c outside temps compared to 5w40.. right? for start up at least..

i understand that it meets requirments, but at what point would it be more efficient to run lower weight for startup

 

people on bobistheoilguy have said that their engines have started up fine at freezing. you will probably get a lot more and better response if you asked the same question there. i say just go with what you feel comfortable with. you could probably switch to a 5w-40 syn. in the winter and change the oil less frequently and during the summer you can switch to a 15w-40 and change more often.