Dodge cummins oil question....

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92 Dodge 1 ton p/up with 120,000 miles. Inline 6 turbo diesel. Currently using rotella t 15w40 but would like to switch to Full Synthetic. Would a 5w40 Full Synthetic be too thin? Its the only weight I can find Full Synthetic at my local walmart. The truck Has always seen 15w40 so I'm just making sure before I screw anything.....also what is a good robust oil recommendation? TIA

 

[MGregoir]

The 40 is what matters, not the 5W. You should be fine.

The 5W part is rated at -30 Celsius and takes into account how hard it is for the engine to pump that cold oil, and the 40 takes into account that at 100 degrees Celsius (212 degrees F, boiling point for water) that it is of a certain viscosity at that point.

Synthetics are a lot better when it is cold, which is why they are usually 5W-40. Rotella T synethic, Mobil Delvac 1 or Mobil 1 Turbo Diesel Truck and Chevron Delo 400 synthetic are all really good, "million-mile" 5W-40 oils that will offer you great performance at both ends of the spectrum.

Especially considering you are in Michigan, the 5W-40 will help you a bunch once it is going to be winter time.

 

[tsmay51]

I would just run 15w40 in the warm months. Switch to 5w40 once it gets really cold. Here in Texas I just run 15w40 year round. We may see 15 days below 32F a year. It just doesn't get cold enough to warrant using the synthetic stuff.

 

[courierdog]

If you run without being plugged in then I strongly suggest the use of full synthetics. I run 15w40 non synthetic year round. As I run Hot Shot the truck stays plugged in 365 when home in the garage and I use the cab heater on layovers when away from home. while the synthetics are superior for cold starts, I have found with keeping it plugged in and with the cab heater the block is never cold. The engine reaches operating temperature within 5 minutes. Even with full synthetics it will not improve much on this.

 

[D-Roc]

Originally Posted By: courierdog
If you run without being plugged in then I strongly suggest the use of full synthetics. I run 15w40 non synthetic year round. As I run Hot Shot the truck stays plugged in 365 when home in the garage and I use the cab heater on layovers when away from home. while the synthetics are superior for cold starts, I have found with keeping it plugged in and with the cab heater the block is never cold. The engine reaches operating temperature within 5 minutes. Even with full synthetics it will not improve much on this.


Totally agreed...my only concern with running regular has been on extreme cold days (-38 here in Edmonton in February), even plugged in (block heater only, block may be getting heat from the block heater, but the oil/pan will be a little colder). I have often wondered how well regular does at these temps with just the block heater. That's why I have the oil pan heater as well...

 

[1040 WreckerMan]

The oil pan heater is a very good idea at those temps as it is much more effective as far as engine startup conditions are concerned. The block heater only heats the coolant, so the temp gauge on the dash may show full op temp but the oil may not be much over 20* above ambient at that point. I prefer operating equipment based off of oil temps rather than water temp.

 

[MGregoir]

This is a gas engine application but a guy I know ran 400,000 km on a Chevy 350 before tearing it down. Block heater side of the block was fine but the cylinder bores on the cold side were visibly scuffed. From then on he added a second block heater to vehicles he was keeping long term.

 

[warfighter]

I have a 98 dodge cummins and I used to use whatever oil that was the cheapest. Oil is Oil right? My truck has 270K on it and would use a quart every 900-1000 miles. I tried Schaeffers 7000 15-40 in it and it made a huge difference. I now add a quart every 4000 miles it starts right up in the cold months. I run the oil for 10K also very important is the quality of oil filter you use. I use the Donaldson endurance long life oil filter they are about 15.00 This combo works great for me. I don't sell schaeffers and don't work for them but they got some good oil.
;

 

[TurboLuver]

Here in SW Ohio I run 15w40 conventional from around May-November then 5W-40 synthetic the rest of the year in my 01 Cummins.

 

[heyjayman]

At my hobby farm, I run Esso XD-3 15w40 from April-October. From October to next April, I run Esso XD-3 0W-40 or 0W-30. However, our winters can dip to -40