Oil viscosity change for a 5.7 Hemi?

[mrmikey]

The recall of the GM engine and the 'warranty' fix of going with a heavier weight oil got me thinking. I've got a '19 Ram 1500 with the 5.7 Hemi, 90K on it now and it calls for 5W-20 oil which I've always used. Seems as if one of the problems with this engine is flatspotting the roller lifters. I do an oil analysis every oil change and there's no wear or non to speak of nor particles in the filter.
What's the collective thoughts of going to a heavier oil say a 10W-30 or a 15W-40?. The lighter oils were supposedly spec'd for mileage which I find hard to believe oil viscosity will make a hill of beans difference on a warm engine. My concern is oil flow at lower temps. Summer's not so bad but winters get as low as -10C around here and I don't want to cause starvation issues. Even saying that, I would think there's more than enough residual oil left on an engine to lubricate it during a cold start until the oil starts flowing. Thoughts?

 

[big bubba]

can't really say which viscosity, but i would be hesitant of using 15/40 in an engine that calls for 5/20 esp on those cold starts given your location

 

[mrmikey]

True, 15-40 is a major jump in viscosity from 5W-20.

 

[LouNY]

The recall of the GM engine and the 'warranty' fix of going with a heavier weight oil got me thinking. I've got a '19 Ram 1500 with the 5.7 Hemi, 90K on it now and it calls for 5W-20 oil which I've always used. Seems as if one of the problems with this engine is flatspotting the roller lifters. I do an oil analysis every oil change and there's no wear or non to speak of nor particles in the filter.
What's the collective thoughts of going to a heavier oil say a 10W-30 or a 15W-40?. The lighter oils were supposedly spec'd for mileage which I find hard to believe oil viscosity will make a hill of beans difference on a warm engine. My concern is oil flow at lower temps. Summer's not so bad but winters get as low as -10C around here and I don't want to cause starvation issues. Even saying that, I would think there's more than enough residual oil left on an engine to lubricate it during a cold start until the oil starts flowing. Thoughts?

From what I have seen and read on the various RAM forums it seems like the "lifter" tick is often caused by malfunctions in the MDS system which is what deactivates 4 cylinders when it thinks the engine doesn't require them for power. I would be leery of changing an oil that has worked for 90,000 miles, unless to a 5W-30.

 

[JJT]

If the used oil analysis is good why would you change from the OEM recommendation? If you are running conventional oil I'd switch to a named brand 5w-20 synthetic.

 

[mrmikey]

If the used oil analysis is good why would you change from the OEM recommendation?

My thinking is a slightly thicker oil would give better protection.

If you are running conventional oil I'd switch to a named brand 5w-20 synthetic.

I'm using a synthetic, Kirkland made by Warren which is supposed to be a good brand. I change it regularly at 12,000KM (7,500 miles) with the oil life reading still at 25% remaining. 90%+ of my driving is at highway speeds and usual runtime is a minimum of 20 minutes a shot. As I've said, I check the filter for bits and send it (oil) for analysis with good results.

 

[5030]

From what I have seen and read on the various RAM forums it seems like the "lifter" tick is often caused by malfunctions in the MDS system which is what deactivates 4 cylinders when it thinks the engine doesn't require them for power. I would be leery of changing an oil that has worked for 90,000 miles, unless to a 5W-30.

I wonder if Holley Performance offers a delete kit? I installed one in my wife's Suburban V8 and it resulted in no loss of average fuel mileage (not that it was all that good to begin with) but it did eliminate the 'tick' that the cutout produced and it was using oil at the rate of 1.5 quarts between changes. Once I installed the Holley delete unit, it quit using oil entirely and the 'tick' vanished.

I've also read that the VVT assemblies on the Hemi engine can be an issue but not owning one, not sure of that for certain.

 

[ConawayFarms]

If your oil analysis is clean, I'd stick with the 5W-20. Switching to a heavier oil could mess with oil flow at low temps. If you're set on a change, maybe try 5W-30, but honestly, I wouldn't overthink it. If everything's running smooth, don't fix what ain't broke.

 

[RandyT]

From my research a few years ago from forums with people that tried using oil other than recommended 5w20 was heavier oil doesn't play nice with the MDS system. Basically expect an miss at idle because the engine won't come out of MDS mode.

 

[5030]

Just install a delete and be done with it. Those cylinder delete's are an excuse for manufacturers to attain their CAFE mileage stats. They add unnecessary components and shorten engine life by drying out the deleted cylinders and in the case of GM engines, cause excessive oil consumption.