5w40 or 15w40?

[LZimmerman]

Guys,

I have read a number of posts on here about 5w40 or 15w40. I just bought a 2005 dodge cummins with 125,000 miles on it. Bought it from the original owner and he has always used 15w40 rotella. I was reading and looks like the manual recomends 5w40. I use Rotella 5w40 synthetic in my TDI volkswagen and have no problems with it, just trying to get some input what I should use and if it will hurt anything at this point. I am familiar with Gen 2 engines, which I use to run either Cat 15w40 Deo or Valvoline premium 15W40.



Thanks,

Scott

 

[steved]

Both are a 40 weight oil, one is synthetic and the other is conventional. I want to remember that both 15w40 and 5w40 are recommended for the 3rd gen?



Pick what oil suits you in a 5w40/15w40, and run it without worry.

 

[macdaddy]

Go with the 5w40 Synthetic even though it's CJ rated it still has decent TBN properties, and as good or better than Amsoil CJ and a hell of allot cheaper (WalMart).



If and whenever Royal Purple stops CI4 Plus ill be running it.



Mac

 

[JaredH]

I ran 5W-40 Rotella in my truck at around 60K miles for one oil change. It would give a puff of smoke at start-up almost like valve seals in a gasser... at that point I was concerned it was injectors. Changed back to 15W-40 and no more puff, been running 15W-40 ever since. Nothing else was changed, no other data, just using the "mirror meter. "



That was my experience... The manual does recommend 5W-40 for any temp, only recommends 15W-40 for temps over -18F, lol.

 

[LZimmerman]

yeah you are right. At -18 in Central Illinois? if it is that cold, I am staying inside and look at my truck out the window. Thanks for the input all of you!

 

[Turbo_Bob]

Unless you live in very cold areas, which is where the 5W-40 would be a good choice, the 15W-40 is all that is needed for our CTD.

5W goes down to -30F and 15W goes down to -10F

Motor Oil Viscosity

 

[Edgemann55]

Live in Northern Nevada and we have had -13 mornings with the wind blowing. All I have run is 15/40 Amsoil since 20K. I have 80+K on her now and she starts fine in any weather. Change it out once a year as I run 15-20K a year. Dealer wanted me in every 5k for a oil change at 80. 00 a pop.

 

[amsoilman]

Unless you live in very cold areas, which is where the 5W-40 would be a good choice, the 15W-40 is all that is needed for our CTD.



5W goes down to -30F and 15W goes down to -10F



Motor Oil Viscosity

In The Amsoil Synthetics, the 5W-40 (CJ-4) oil has a pour point of -51F. The HDD&Marine 15W-40 (CI-4+) has a pour point of -44F, so with the use of these oils in cold climates, they really shine.

 

[AABEN]

I run 15-40 the year round premiun blue from day one. All the reports from Blackstone lab has all ben very good. the last time I changed oil they said to go to 9000 miles. I have 10. 000 miles + on it will change it next week. Will send in sample for test will let you know how it came out on the test.