High ICP
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,345
Likes: 5,941
From: Lake Hartwell, GA
FTE heroes to the rescue again! 
7.34x4, congratulations on getting your issue solved and if you still have the 15w40, you can run it in the summer time. A lot of people in the northern part of the country run two different oil blends based on the season.
7.34x4, congratulations on getting your issue solved and if you still have the 15w40, you can run it in the summer time. A lot of people in the northern part of the country run two different oil blends based on the season.
Got Data?
Joined: Dec 2012
Posts: 4,239
Likes: 1,369
From: Lake Stevens, WA
Very cool, 7.34x4. Let's keep an eye on that IPR%. I bet if you drive it around a bit and do some WOT runs, you'll dilute the remnants of that heavier oil and maybe the IPR% will head back towards the normal range. Let us know.
Post Fiend
Joined: Sep 2003
Posts: 6,096
Likes: 26
From: Mesa AZ
I've never heard of "Mobil 15w40 extreme synthetic", but at 35 degrees, the owner's manual suggests 10W-30 might work better over the winter than 15W-40.
If you like synthetic, then a 5W-40 synthetic would be a good choice for winter.
Is that what you meant to type, 5W-40?
There can be a huge difference in cold start performance between 15W-40 and 5W-40.
If you like synthetic, then a 5W-40 synthetic would be a good choice for winter.
Is that what you meant to type, 5W-40?
There can be a huge difference in cold start performance between 15W-40 and 5W-40.
Thread
Thread Starter
Forum
Replies
Last Post
Fordenthusiasts
1999 - 2003 7.3L Power Stroke Diesel
8
May 10, 2016 10:28 PM
