M1 5W-40

dewfpo · January 27, 2005

My new 05 has 496 miles on it and I am planning on doing the first oil change at 1K. I know the truck comes with dino 5W-30 in it and that's what GM recommends but ...... I was thinking that I might sleep a little better with synthetic 5W-40 in the 'ole 8.1.

Any thoughts or comments?

DEWFPO

496 CUBIC INCHES · January 27, 2005

It would be a great choice for your truck. The 5-40 T&S is re-labled Delvac 1 which is Mobils best oil. Don't fall into 3000 mile mode either. I'd go at least 5000 miles between changes with the 5-40. If it were my truck I'd probably go 7500.

If it were easier to find near me I'd run it in a heartbeat. The only place around me that has it is Schucks,and I won't set foot into a Schucks.

Mighty HD · January 27, 2005

Will 5w40 really make that much of a difference in the 6.0/8.1?

whitesnake01 · January 28, 2005

Will 5w40 really make that much of a difference in the 6.0/8.1?

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I run M1 15W50 in my 93 454. Runs great. Consumes barely any oil at all. I've run it on synthetic since about 10K. Keeps the oil pressure up when it gets hot, for one thing. Just started using the M1 Truck & SUV formula in the new DMAX. Too soon to tell if things are different. Need to have a few hot days with trailer behind, first!

Valsport · January 28, 2005

What are you guys' recommendations on running a 40 weight oil or the M1 truck and SUV formula in a 5.3 with 86K? I have been running M1 5w 30 since 51K miles, and Valvoline dino before that.

Beaux Duke · January 28, 2005

Will 5w40 really make that much of a difference in the 6.0/8.1?

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Keeps the oil pressure up when it gets hot, for one thing. Just started using the M1 Truck & SUV formula in the new DMAX. Too soon to tell if things are different. Need to have a few hot days with trailer behind, first!

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Forcing a thicker liquid through all the oil passages will definitely up the pressure on the gauge but it doesn't mean you're getting more oil through the system. A thinner oil will flow more freely and provide better lubrication especially when it gets hot.

Mighty HD · January 28, 2005

in my 03 work F150, lately it has been burning a TON of oil---2+ quarts every

5000 miles. I assume it's because my run time/idle time is 13+ hrs a day in hot weather. It runs the el-cheapo jiffy lube penzoil 5w20. Next time I'm going to have them dump 10w30 in it and hope it will do well.

I prefer to use 5w30 M1 in the truck--it sits all week so when I start it up, I want the oil flowing fast. I even thought about running 0w30...

bigdogs · January 29, 2005

I switched my DMax to it in the fall and has worked out fine. Oil pressure is still great.

whitesnake01 · January 29, 2005

A thinner oil will flow more freely and provide better lubrication especially when it gets hot.

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That is a bit too sweeping of a statement. Free flow does not imply better lubrication. It might suggest faster return to the pump, though, which may not be a desirable property for some engines.

I also thought synthetic oils were better at retaining their properties for a wider range of temperatures, while traditional oils get thinner (faster) under heat. This is why your truck manual at least used to suggest two different oils, depending on outside temperature.

My experience tells me that in my particular case, where I have abused my 454 for prolonged periods under heat, have not resulted in an increase in oil consumption. I've had the truck for almost 12 years. I have no scientific data to suggest a key reason for this is the use of M1 15W40. But I would not mind betting is has not made matters worse than running a thinner oil... and I would not be surprised if this has helped the engine more than running the recommended dino. Thicker oils also stay put longer in the engine rather than washing back down. I am not suggesting a thicker oil is good for everyone.

rascal · January 30, 2005

what brand of oil does chevy use from the factory?

number9 · January 30, 2005

I have used Mobil1 10W-30 or 10W-40 full synthetic and Mobil1 M1-201 filter in my 99 Z-71 since first oil change - truck now has 117,000 miles.

I bought an 02 GMC 2500HD 6.0 with 27,000 miles on Friday and plan on using M1 in it also when I change the oil this week.

496 CUBIC INCHES · January 31, 2005

what brand of oil does chevy use from the factory?

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Mobil conventional 5-30

tomm · February 4, 2005

I had it changed today to mobil I 5-30.Ive used this oil in other vehicles and never feel guilty if I go 5 or 6 thousand between changes.2500HD 6.0 auto

Bud · February 4, 2005

Anybody use Valvoline Synpower?

rascal · February 8, 2005

anyone have any problems out of synthic blended oil. mobil 1 5w30 7500mile, is what i'm going to put in as soon as we get a dodge off the rack. 5k oil changes to make it simple, unless the oil change thing decides it needs it before.

the dodge is a v6 with 140k and just lost oil pressure, had a dodge mech looking at it today. no body can figure out why it lost pressure. the oil pump looked fine. so far, we are going to replace the oil pump with screen, and all the main and rod bearing, given the owner doesn't want it fully rebuilt.