JyRO, you assumed I ment valve stems when I wrote "valve rods". I am sorry I did not include the word push as in "pushrods". The I-6 Cummins does not have overhead cams contacting the valve stems. The valve cam is in the 5.9 liter engine block and transmits force through pushrods up to the cylinder head containing the valves.

I can understand that you do not have problems with your engine when starting it in freezing weather, because you wait until oil circulation is present before moving your truck. I do not know what weight of oil you use in the winter. I think MI stands for Minnesota and AL stands for either Alaska or Alabama. If you lived in some areas of Alaska you know what severe cold happens to be.

I said in sub-freezing weather and not just below the freezing point at +32 degrees Fahrenheit. In Northern Alberta the temperature will at times drop to -30 or -40 degrees Fahrenheit below zero during the night with a stong wind blowing to rob the heat off an engine in short order. That is why I have a diesel fired progammeable coolant heater installed on my truck.

The Dodge dealership told me that the problems a few of the owners of the 24V engine were experiencing was with the valve train from them revving a cold engine. They had 15W-40 Premium Blue in the crankcase and this problem was never encountered with the 12V engines. In real cold temperatures the oil is so thick from the cold that the engine will not crank over very quickly. Some of the owners treated their diesels like a gasoline engine and just drove off after starting the engines. It has been so cold here that a vehicle's tires retain their flat spot from the tire sitting on the ground. The flat spot stays out of round for a quarter mile after starting to drive. The vehicle bumps along until the tire heats up a bit and rounds out.

 

whats the difference between straight 30 weight and 15x-40 oil? somehow i picked up 3 gallons of straight 30 last time in autozone and when i got home i realized it was wrong. i didnt put it in the truck luckily but if i did would it have hurt anything?

BTW- i use nothing but rotella because its easily available, and priced reasonable.

 

Actually MI stands for Michigan, and AL stands for Alabama.

In MI, I parked my truck in the garage so my coldest (morning) starts in the garage were right about the freezing mark, maybe a couple degrees above that. There were plenty of days of cranking outside that were below zero, but no kind of -30 junk like that, thank the Good Lord. Even down as cold as that I ran the 15W-40 Premium Blue. I think it's rated down to about 0, but I don't remember exactly. Anyway, I didn't bother to change viscosities, because the majority of the coldest times were mornings when my truck was in the garage at about 32 degrees. So, I stuck with the Premium Blue even though I did crank it up below 0 many many times. It did OK. I would crank it and go back out and start clearing windows lights whatever and let the engine idle for 5 to 10 minutes.

But now in AL, shooooot I don't have to worry about that at all. I don't think we've been into the teens yet! Man, it shore is nice down here!

- JyRO

 

I would not use it for racing, but this time of yr...it would work OK. Take longer to warm things up before engaging drivetrain to be sure oil is flowing.

Actually, best choice, buy some 15-50 and mix it w/ 30 wt in equal amounts..50-50%. Will end up with roughly a 20-40 wt oil. They will mix and work fine!

I mix my companies 3w-30 Nascar oil with 15w-50 "World of Outlaw" oil all the time (because we don't make a synthetic 15w-40).
RJ

 

Straight 30 weight engine oil is good to use in a worn engine or an engine that leaks out oil, but it is too heavy for an engine in good condition. It would be acceptible if the engine is operating in hot tropical conditions. A 15W-40 conventional oil's viscosity will thin down to about 20 weight when it is cold and it will thicken up to about a 35 weight when the oil is hot. If the 15W-40 is a 100% synthetic oil its viscosity will thin down to a 15 weight when cold and it will thicken up to a 40 weight oil when hot. The molecule extenders in a conventional multi-grade oil will not go through as wide a change due to temperature changes as the molecules in a synthetic oil of similar viscosity rating. Synthetic oils keep an engine cleaner than conventional oils will.

I use 0W-30 ESSO Polar Plus 100% synthetic engine oil in our gasoline powered vehicles during the summer and winter seasons. I change engine oil once a year in the late fall. That oil was in our GMC V6 engine when we traveled to Houma, Louisiana just before Hurrican Dennis hit in 2005. I like light oil in the crankcase on starting as the engine oil circulates instantly. In cold weather the thin oil provides little puimping resistance to the engine's starting motor. With heavier viscosity oils, especially in cold weather. it causes a longer duration of dry starts.

 

Straight 30 weight engine oil is good to use in a worn engine or an engine that leaks out oil, but it is too heavy for an engine in good condition. It would be acceptible if the engine is operating in hot tropical conditions. A 15W-40 conventional oil's viscosity will thin down to about 20 weight when it is cold and it will thicken up to about a 35 weight when the oil is hot. If the 15W-40 is a 100% synthetic oil its viscosity will thin down to a 15 weight when cold and it will thicken up to a 40 weight oil when hot. The molecule extenders in a conventional multi-grade oil will not go through as wide a change due to temperature changes as the molecules in a synthetic oil of similar viscosity rating. Synthetic oils also keep an engine cleaner than conventional oils will.

I use 0W-30 ESSO Polar Plus 100% synthetic engine oil in our gasoline powered vehicles during the summer and winter seasons. I change engine oil once a year in the late fall. That oil was in our GMC V6 engine when we traveled to Houma, Louisiana just before Hurrican Dennis hit in 2005. I like light oil in the crankcase on starting as the engine oil circulates instantly. In cold weather the thin oil provides little puimping resistance to the engine's starting motor. With heavier viscosity oils, especially in cold weather. it causes a longer duration of dry starts.

 

I ran Chevron Delo 400 15/40 in my 5.9 Cummings, 1991 Dodge 250 for 15 years. Still have the truck and it has 250K and runs like a swiss watch.

2006 Dodge Laramie, Diesel 6 spd,QC,SWB, PacBrake