RV.Net Open Roads Forum: Tow Vehicles: 5W40 or 15W40 in 6.7 CTD?

RV Blog

  |  

RV Sales

  |  

Campgrounds

  |  

RV Parks

  |  

RV Club

  |  

RV Buyers Guide

  |  

Roadside Assistance

  |  

Extended Service Plan

  |  

RV Travel Assistance

  |  

RV Credit Card

  |  

RV Loans

Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tow Vehicles

Open Roads Forum  >  Tow Vehicles

 > 5W40 or 15W40 in 6.7 CTD?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Next
Sponsored By:
BurbMan

Noblesville, IN

Senior Member

Joined: 09/20/2001

View Profile



Good Sam RV Club Member


Posted: 10/31/20 07:30am Link  |  Quote  |  Print  |  Notify Moderator

So the owner's manual in my 2015 Ram says to use 15W40 oil in the 6.7 Cummins diesel, unless the temp is going to routinely be below 0*, in which case you should use 5W40.

Here on Long Island, the temp rarely if ever even gets to 0*, much less stays under it for any period of time. I'm coming up on my first oil change since I've owned the truck, and I was all set to stay with 15W40. However, guys on a couple forums are saying they use 5W40 year round.

Please let's not get into a brand war or discussion about dino vs. synthetic, but I'm interested to know what weight oil you guys are using.


2015 Ram 3500 SRW 4x4 Laramie Crew Cab Long Box, Cummins diesel
2002 Lance 811 Slide-In Camper
SOLD: 2008 Terry 34' TT
SOLD: 2001 K2500LT 8.1L Suburban

Lance 811 Renovation Story!
Project Complete!
Maiden Voyage!


DownTheAvenue

Sunny South

Senior Member

Joined: 07/30/2014

View Profile



Posted: 10/31/20 07:41am Link  |  Quote  |  Print  |  Notify Moderator

I am always in favor of doing what the owner's manual, written by the people who designed and built your vehicle, says to do rather than people on an internet forum say to do.

SweetLou

La Quinta, CA USA

Senior Member

Joined: 06/03/2003

View Profile


Offline
Posted: 10/31/20 07:45am Link  |  Quote  |  Print  |  Notify Moderator

15-40 should be just fine


2013 3500 Cummins 6.7 Quadcab 4x4 3.73 68FE Trans, 2007 HitchHiker Discover America 329 RSB
We love our Westie


Lwiddis

Monterey, California

Senior Member

Joined: 08/12/2016

View Profile



Good Sam RV Club Member

Offline
Posted: 10/31/20 07:57am Link  |  Quote  |  Print  |  Notify Moderator

Follow Ford’s recommendations. My gas Chevy is 0W20. Light stuff!

* This post was edited 10/31/20 08:08am by Lwiddis *


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watt solar-parallel & MPPT, Trojan T-125s. TALL flag pole. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist14 yr. Army vet-11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad


BurbMan

Noblesville, IN

Senior Member

Joined: 09/20/2001

View Profile



Good Sam RV Club Member


Posted: 10/31/20 08:00am Link  |  Quote  |  Print  |  Notify Moderator

This is what the owner's manual says:

[image]

Cummins12V98

on the road

Senior Member

Joined: 06/03/2012

View Profile


Offline
Posted: 10/31/20 08:06am Link  |  Quote  |  Print  |  Notify Moderator

100% run 15-40. If it's synthetic the pour point is not much higher than the 5-40.


2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

ShinerBock

LVTX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 10/31/20 08:34am Link  |  Quote  |  Print  |  Notify Moderator

There have been hundreds of thousands of Cummins owners that have gotten hundreds of thousands of miles out of their truck running regular 15w40 even in colder climates. Not saying that running 5W40 is bad or not needed, but most who do only do it for "cheap insurance" because they "feel" that it will extend the life of their engine. How long while it extend the life of the engine? They don't really know, but it makes them feel better.

Could be that 5w40 extends the life of the engine an extra 10k miles or 100k, but if you are only keeping the truck for 300k miles and 15w40 will easily get you there then what is the point of spending extra money on something that will extend it past that? You are just spending extra money that will only benefit the next owner.

Basically, most(not all) are doing it based on emotion rather than actual data or need. Some do actually need to run 5w40, but most do it because makes them feel better that they are doing a good thing extending the life of their engine. Not saying this is bad thing because a lot of people(including me) spend lots of money on things that make them feel better, like beer [emoticon]......

* This post was edited 10/31/20 08:40am by ShinerBock *


2014 Ram 2500 CTD
Highland Ridge Silverstar 378RBS

BenK

SF BayArea

Senior Member

Joined: 04/18/2002

View Profile



Posted: 10/31/20 08:50am Link  |  Quote  |  Print  |  Notify Moderator

IMHO...depends on how hard you plan to drive it...

I'd go higher viscosity


-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...

ShinerBock

LVTX

Senior Member

Joined: 02/22/2015

View Profile



Posted: 10/31/20 09:05am Link  |  Quote  |  Print  |  Notify Moderator

BenK wrote:

IMHO...depends on how hard you plan to drive it...

I'd go higher viscosity


Both have the same viscosity grade of 40 at operating temp so they are about the same when driven hard with 15w40 having the slight edge. It is their cold temp viscosity grade that is different which mainly only comes into play when the oil temp is below 30F. One has a cold viscosity grade of 5W and the other 15W.

[image]

* This post was edited 10/31/20 12:30pm by ShinerBock *

ppine

Northern Nevada

Senior Member

Joined: 07/04/2016

View Profile


Offline
Posted: 10/31/20 09:20am Link  |  Quote  |  Print  |  Notify Moderator

Follow manual. Simple.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 6  
Next

Open Roads Forum  >  Tow Vehicles

 > 5W40 or 15W40 in 6.7 CTD?
Search:   Advanced Search

Search only in Tow Vehicles


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.