Oil viscosity change for a 5.7 Hemi?

[kozal01]

I would not change the cold viscosity from what it is. Oil flow at cold starts is important, especially with all the components that function with oil pressure. I wouldn't hesitate to run a 5W-30 though. My old 5.4 3V Ford V8 was switched to 5W-30 at the recommendation of many experts when I got the truck at 50K miles, when I had the engine open at 120K to do preventative work it had no wear and the phasers, chain tensioners, cams and followers were all in perfect shape. Proper oil change intervals and good quality synthetic oil are just as important as the oil weight in my opinion.

 

[JRH02]

I live far rural and on any drive it involves some amount of highway speeds. I had a 2005 Charger with the 5.7 for trips to town or the far away big city. The cylinder deactivation worked fine but did zero or very little for mileage. I later traded it in for a 2007 Charger SRT8. For all the horsepower that SRT8 had, if I kept my foot out of it, I lost only 1 or 2 MPG on the same roads and under the same driving habits. But it needed premium and that stunk. And if WAS hard to keep my foot out of it

As for oil and protection/longevity you said you are already running 100% synthetic. Excellent. DON'T change the specified oil weight, in my opinion. Both the 5.7 & 6.1 are good engines.

 

[Mister3]

My 07 ram hemi took 5-20 oil and if i put in 10-30 it would throw a code

 

[mrmikey]

Well after all the discussion and opinions both here and other forums I think I'll stick with what I've got, 5W-20 synthetic. There are conflicting views and both ways have valid, good points but I think the leave it as is is the better idea. Not by a landslide by the majority LOL.

 

[mllud]

The new oil pumps in some new engines are HVLP pumps. They have gotten away from gear pumps for oil pressure.
A heavier viscosity oil could backfire depending on how fast on engine startup the new style High Volume Low pressure Oil Pumps would build operating oil pressure.

That being said I am old school in not liking these low viscosity oils especially on the crankshaft. That film of oil is important in my thinking.

 

[DarkBlack]

Everyone has pretty much hit it on the head. The MDS requires the 5w-20. You can turn off the MDS but starting I think in 2016 the computers are locked. You can get around it by getting an unlocked pcm and get a programmer but you’re getting over a $1000. You can delete the engine, it’s not difficult but you have to crack the engine open, not simple either.

I have a 2010 Dodge Challenger and turned off the MDS with a programmer. I was a little surprised by how much it hurt fuel mileage, I’d say 10%. They have improved the programming on the MDS, on my 2010 it’s was very annoying, turning off and on a lot. On my wife’s 2019 300c, it’s much better.

Most legitimate 5.7l “tick” problems at idle are caused by broken exhaust manifold studs, allowing a tiny bit of exhaust sound to sneak past the head/manifold interface, but most folks blame the MDS system.
MDS isn’t even active at idle.
At idle, the MDS lifters are locked up, like a normal lifter
Most vehicles allow de-activating MDS by simply pressing your electronic shift button to the highest manual “gear”. Of course you unfortunately need to do this every time you change to “D”.

 

[RandyT]

Most legitimate 5.7l “tick” problems at idle are caused by broken exhaust manifold studs, allowing a tiny bit of exhaust sound to sneak past the head/manifold interface, but most folks blame the MDS system.
MDS isn’t even active at idle.
At idle, the MDS lifters are locked up, like a normal lifter
Most vehicles allow de-activating MDS by simply pressing your electronic shift button to the highest manual “gear”. Of course you unfortunately need to do this every time you change to “D”.

Tow/haul mode also deactivates MDS.

 

[JRH02]

Tow/haul mode also deactivates MDS.

I was trying to remember it there was a way to disable 'MDS' on the 5.7L Charger. I'm pretty sure it didn't have a Tow/Haul mode

 

[dodge man]

Most of the Hemi cars, be it a Challenger, Charger, or 300 have a way to manually shift. The older ones had Autostick, you slap the shifter right or left to shift up and down. This keeps the MDS turned off. Going down the highway it’s not an issue but if you pull up to a stop sign it will try to hold 1st gear when you pull away. Full throttle it will upshift in autostick automatically but most people don’t drive that way.

It’s the same way with paddle shifters the newer models have. Use the paddles MDS is turned off.

 

[paulsharvey]

As someone who has a 19 Ram 1500, 5.7L; that also has destroyed two work truck ram 1500, 5.7L hemi. Idle... They don't oil well at idle. Avoid just idling. Yeah, a minute here and there, fine, but avoid those 30 minute idles while wife is in the store, or letting it warm up for an hour while you do other things.

Keep in mind those work trucks often idled for hours and hours. Sitting working on computer, waiting on a crew, eating lunch, waiting out bad weather, ect. They both got 5000 mile or 7500 oil changes, but how many hours was that?