10w40 vs 15w40?

[SecondMonkey]

I have a Jeep with the 4.0 inline 6 and about 215,000 miles. I know these engines like 40 weight oils, and it's getting old, so that's what I use. I've been using Chevron 10w40 for a while now, but I'm wondering if maybe 15w40 would be better? It burns a small amount of oil but I think that is to be expected at this mileage.

Most of my driving is very short trips (less than 20 miles round trip) and I usually change it around 3k miles because of that. This time a year it rarely gets below 30 degrees, and I rarely start the engine below 40 degrees. Do you think a 15w40 might work better? I'm thinking maybe Delo diesel oil.

 

[Towel_Rail]

I'd use the 15W40 HDEO on general principle.

 

[Gary Allan]

I think a 10w30 would be better ..and maybe Auto-Rx. Your round trip length makes oil temp is sub-optimal for most of the time. This isn't as much of an issue for the moisture and fuel ..but you're probably at a 50 or 60 weight for most of the trip.

But you can use whatever 40 weight you please.

 

[mechtech2]

Gary Allan has a very valid point.

 

[Towel_Rail]

Agreed. I glossed over the "short trips" bit.