10W30 oil for Dodge Magnum SXT?

[Oldyellr]

I just recently bought a 2005 Dodge Magnum SXT with the 3.5 liter V6. The recommended oil for this engine is 10w30, which is really odd, because most cars for the last 25 years have called for 5w30 and 10w30 is not all that common anymore.

As I have come to understand oil viscosity, 5w30 and 10w30 are the same at operating temperature, but 5w30 is thinner at 0 degrees cranking temperature to facilitate easier starts and quicker oil distribution. In fact, given 5w30's shallower viscosity curve, it should even be "thicker" that 10w30 at above normal operating temperature, thus better. In fact, I use 0w30 synthetic in my Camaro for this very reason when the "recommended" oil is 10w30.

So what is it about the 3.5L Magnum that they specify 10w30 and would I be just as safe using 5w30 or even 0w30 synthetic?

 

[Merkava_4]

My Buick specifies 10w30 as preferred and 5w30 below 60F as optional.

The engineers don't trust 5w30 for obvious reasons.

 

[VNTS]

Back then 10w30 was more shear stable, my 02 WJ also recommended 10w30.

A synthetic would be a good choice.

How many miles on it and how is the coolant and timing belt.

 

[Nick1994]

Originally Posted By: Merkava_4
My Buick specifies 10w30 as preferred and 5w30 below 60F as optional.

The engineers don't trust 5w30 for obvious reasons.
Merk, you've been on here a lot longer than I have and know better than that. 5w30 wasn't as shear stable back then, it is now. My grandmother's 2002 Chevy Trailblazer (same company as your car was made) calls for 5w30 in all temperatures.

 

[SR5]

My 2006 GM also says 10W30, but I would have no problems with a good 5W30 synthetic.

It's just with mineral oils 10W30 is more shear stable than 5W30 for regular PCMO. Step it up to a synthetic oil and you are fine on 5W30.

 

[Chris142]

Lots of 10w30 still on shelves. Even 10w40.

 

[4wd]

Had a 2007 Chrysler 300 - same mill - it called for 10w30 ... Mobil 1 High Mileage was the flavor.
Son still has the car - 125k and runs good ...

 

[barkingspider]

I would just use 10w30 and call it a day

 

[mjoekingz28]

Barkingspider, I believe the guy is in Canada. This winter, a 10w30 might be inadequate. Our lows are like their highs.

 

[OVERKILL]

Originally Posted By: SR5
My 2006 GM also says 10W30, but I would have no problems with a good 5W30 synthetic.

It's just with mineral oils 10W30 is more shear stable than 5W30 for regular PCMO. Step it up to a synthetic oil and you are fine on 5W30.


This. A synthetic 5w30 would be fine, they are/were concerned about shear with a conventional oil.

 

[Gene K]

10W30 in many cases still has a higher HTHS (because of temporary shearing of VII) and is more shear stable.

Example:

Synthetic 5W30
10.93 cSt @ 100C
3.2 HTHS @ 150C
9.43 cSt Shear Stability Test

Synthetic 10W30
10.58 cSt @ 100C
3.32 HTHS @ 150C
9.98 cSt Shear Stability Test

After permanent shearing 5W30 would likely end up under 3.0 HTHS where 10W30 would likely end up over 3.2 HTHS.