Should I run 5w30 in my ram hemi for towing

[Gokhan]

Originally Posted By: e55amgbenz007
Originally Posted By: Gokhan
Originally Posted By: Jaymie
Interesting, is that because it won’t flow as quickly?

No, thicker motor oil runs hotter because higher HTHS viscosity (HTHSV) causes more friction in the bearings. That is why the fuel economy drops with the increasing HTHSV.

From your oil temperatures (convert them to C first so that they would be useful) -- 102 C without towing and 112 C with towing -- definitely go with 5W-30 for towing. It would give an extra margin of safety for towing. There is probably no need for 0W-40 unless you want to do extreme towing.

You can play around with the Widman calculator for the operational viscosity. Just plug in the KV40 and KV100 values from the data sheets.

https://www.widman.biz/English/Calculators/Operational.html

That doesn't take into account the need for higher viscosity (particularly HTHSV) because of more load in the bearings but at least it takes into account the oil temperature.

Here is the fundamental curve of lubrication -- Stribeck curve -- that tells you what happens when you change the HTHSV (n [eta]), load (P), and RPM (v). In the bearings you want to stay in the hydrodynamic-lubrication region:

Wait, I am lost here. Engines, such as the European variety that require a higher HTHS film strength are actually increasing the friction/wear with the requirement?

There are at least two contributions to friction here. The first is the boundary friction, which is the friction that happens when the two surfaces directly make contact. This happens in the boundary-lubrication region. The second is the the viscous friction, which is the oil's internal friction. This happens in the hydrodynamic-lubrication region. Boundary friction causes wear but the viscous friction does not. In the hydrodynamic-lubrication region, there is a thick oil film separating the surfaces. Viscous friction increases with the thickness of the oil film but does not cause wear as long as the minimum oil-film thickness (MOFT) is greater than the surface roughness and/or contaminant-particle size. So, fuel economy drops as you move further right on the Stribeck curve but the oil-film thickness increases and the margin of safety against oil-film collapse or against abrasive wear by surface roughness or contaminant particles in the bearings increases.

 

[Shannow]

Good post Gokhan.

That's one of the "intuitive model" failures in lubrication.

Often there have been people who state that because (for example) 0W20 has lower overall friction, it must have lower wear...this is just the reverse, of an applied intuitive logic.

 

[demarpaint]

I wonder if/when people will be saying should I run a 0W16 oil for towing, instead of a 20 or 30 grade oil?

 

[Mitsu_Joe]

I’d also use 30W oil with shortening the OCI by ~50-70%. Then you should be safe.

Those new 20W oils are a way for manufacturers to obtain slightly better emissions and y’all know how much they willingly sacrifice when it comes to that topic... Therfore as said should be noted that less friction =/= less wear, althought some of those 20W oils provide very good wear protection.

When t comes to hard driving I would definetly stick with a heavier base oil and shorten the intervals a bit. To all people that are concerned that modern engines couldn’t handle thick oils: the regular Mustang is by factory taking 20W oil, with the optional trackpackage it is advised to take 50w oil, with the same block and oil bores...

 

[OilUzer]

Originally Posted By: Gokhan
...
There are at least two contributions to friction here. The first is the boundary friction, which is the friction that happens when the two surfaces directly make contact. This happens in the boundary-lubrication region. The second is the the viscous friction, which is the oil's internal friction. This happens in the hydrodynamic-lubrication region. Boundary friction causes wear but the viscous friction does not. In the hydrodynamic-lubrication region, there is a thick oil film separating the surfaces. Viscous friction increases with the thickness of the oil film but does not cause wear as long as the minimum oil-film thickness (MOFT) is greater than the surface roughness and/or contaminant-particle size. So, fuel economy drops as you move further right on the Stribeck curve but the oil-film thickness increases and the margin of safety against oil-film collapse or against abrasive wear by surface roughness or contaminant particles in the bearings increases.


Very informative post!

When I bought my truck and it specified 0W-20 i wasn't very comfortable with that spec but it was just based on my intuition and didn't have any proof of scientific data ... That was the main reason I ran into BITOG. Later found out that OM also states that higher viscosity can be used under extreme speed or load or something like that but kind of hidden imo and nothing like CAUTION/NOTE or bold letters given the fact that most people may tow or carry heavy load with their trucks ... However 0Wx20 is listed and stamped everywhere!

Back to my question, assuming "surface roughness and/or contaminant-particle size" does not change by much from day 1 (going to grocery store) to day 2 (towing a heavy load), the heat is what's reducing the oil-film thickness and can cause problems by lowering MOFT. Basically 20 weight oil is more susceptible to oil-film reduction than 30 weight oil. Is that correct?

Not my intention to open Pandora's box but how would that compare to conventional oil in general? Would 20 weight synthetic retain (under more heat) the oil-film or the MOFT better than 30 weight conventional oil?
Thanks!

 

[AVB]

I am going to say no on that last ? but there are too many variables. It probably could go either way depending on what 2 oils you are comparing and at what temp.

 

[SteveSRT8]

Originally Posted By: billt460
Originally Posted By: SR5
If the MDS has problems with moving from a 20 grade to a 30 grade oil, then how does it work when it's cold?


It doesn't. The MDS system remains inactive until the engine and oil reach operating temperatures.


In our 14 RAM 5.7 the MDS engages within one minute of startup.

 

[Triple_Se7en]

Originally Posted By: SteveSRT8
Originally Posted By: billt460
Originally Posted By: SR5
If the MDS has problems with moving from a 20 grade to a 30 grade oil, then how does it work when it's cold?


It doesn't. The MDS system remains inactive until the engine and oil reach operating temperatures.


In our 14 RAM 5.7 the MDS engages within one minute of startup.


Startup noise using 30W Steve? What filter?

 

[fins]

I would run 10w-30..........but that's me

 

[OilUzer]

Originally Posted By: fins
I would run 10w-30..........but that's me

not a bad idea imo if the 10W meets your winter spec. Was thinking about doing that if I was towing a lot which typically happens in summer months!

 

[SteveSRT8]

Originally Posted By: Triple_Se7en
Startup noise using 30W Steve? What filter?



May be slightly quieter, no noticeable change in oil temps, mileage unaffected, still incredibly strong. We run the high end Fram because we use the OLM which goes to 8-9k miles sometimes with all the high speed stuff my Wife drives.


The Hemi/MDS thing is greatly over exaggerated here and other forums across the web. The simple facts are newer gen hemis run great on almost any oil.

 

[02vito]

With the oil temps you cite, I would consider an aftermarket oil cooler provided it will not affect your warranty.

Re oil viscosity, if 5W-30 is not an option in the owner manual you may be risking your warranty.

 

[demarpaint]

Originally Posted By: 02vito
With the oil temps you cite, I would consider an aftermarket oil cooler provided it will not affect your warranty.

Re oil viscosity, if 5W-30 is not an option in the owner manual you may be risking your warranty.


I think the aftermarket oil cooler will impact the warranty more than running 5W30.

 

[GMBoy]

Congrats on the RAM!! I love mine, a 2017 RAM Limited. Its an awesome luxury truck and i also have the air suspension. As nice as mine is, the new 2019 raises the bar even more! I am waiting another year or 2 before I get another because the 1st year bugs potential.

Anyhow - I run Mobil 1 0W/30 AFE in my hemi and it does great. I have not lost any MPG compared to the 5W/20 I ran for the 1st 2 oil changes. Go ahead an run 5W/30 with confidence but do consider the OW/30 as a good option too.

 

[andyd]

It isn't the automobile engineers I mistrust regarding the drive toward thiner oils, But CARB and the impetus to wring evry inch out of MPG. And none of them is interested in having you own your car after it is paid for.

 

[SteveSRT8]

Originally Posted By: andyd
It isn't the automobile engineers I mistrust regarding the drive toward thiner oils, But CARB and the impetus to wring evry inch out of MPG. And none of them is interested in having you own your car after it is paid for.

Ouch.

Sad but true...

 

[VNTS]

Originally Posted By: Ramblejam
1500 5.7: 5w-20
2500+ 5.7L: 5w-30
2500+ 6.4L: 0w-40

I run 0w-40 in a 5.7L Durango.


which flavor of 0w-40, any issues with cell codes for the MDS?

I run 5w-30 PU in the wifes hemi overland, no cellcodes

 

[RamAir5]

Congrats on the new RAM! I also bought a 2019 RAM Limited. I too was kicking around the idea of running 5w30 Synthetic. I read on several RAM forums those advocating for and those against 5w30. I just performed my first oil change and I used Kendall GT-1 full syn 5w30. I figured I'd give it a try and if there were issues I'd just switch back to 5w20. No issues whatsoever. The MDS is working without issue, no codes and the hemi runs smoother than with 5w20. The oil temp was 212 degrees with 5w20 and is 216 degrees with the 5w30 due to hydrodynamic friction from the "thicker" oil. Oil pressure is identical. The RAM dealer service manager is a friend of mine and he runs 5w30 in his 2018 RAM hemi.

I was experiencing a brief clicking/knocking in the engine upon startup with the 5w20. It's not there with the 5w30.

I'll run 5w30 in the hemi from now on.

 

[madeej11]

OP,run the 5w30 all year round. It might get a little cold in OK and ARK but not cold enough where you'll need the 20. And no you don't need to use Pennzoil like a couple of people in this thread seem to be stuck on. Dodge Chrysler have a partnership with Pennzoil so they try to push their products. Another guy suggested Mopar oil which is nothing special. Use a decent 5w30 syn of your choice. Happy motoring, enjoy the new rig!

 

[dawgn86]

Ram

What do you think caused the ticking / knocking. I have a slight ticking in my 2012 Hemi. Goes away after about 20 seconds. Not sure if its in the valvetrain or exhaust manifold bolts loose.


Originally Posted By: RamAir5
Congrats on the new RAM! I also bought a 2019 RAM Limited. I too was kicking around the idea of running 5w30 Synthetic. I read on several RAM forums those advocating for and those against 5w30. I just performed my first oil change and I used Kendall GT-1 full syn 5w30. I figured I'd give it a try and if there were issues I'd just switch back to 5w20. No issues whatsoever. The MDS is working without issue, no codes and the hemi runs smoother than with 5w20. The oil temp was 212 degrees with 5w20 and is 216 degrees with the 5w30 due to hydrodynamic friction from the "thicker" oil. Oil pressure is identical. The RAM dealer service manager is a friend of mine and he runs 5w30 in his 2018 RAM hemi.

I was experiencing a brief clicking/knocking in the engine upon startup with the 5w20. It's not there with the 5w30.

I'll run 5w30 in the hemi from now on.