Full Synthetic Oil - Why Not Use 0W-20?

[Texas Woody]

Aside from the owner's manual stating a recommended viscosity rating of 5W-20, what would be the downside of running 0W-20 or even a 5W-30 full synthetic in our 5.7L HEMIs so long as the oil meets the MS-6395 spec? Would Ram not honor their warranty if there were any engine issues?

Been looking at the Pennzoil Ultra Platinum offerings in anticipation my first oil change...

Thanks in advance for your thoughts.

 

[riccnick]

This is covered in the owners manual. Synthetic is fine, as long as it meets the same specs as the conventional or better. It looks like Ram does not recommend any other viscosity of conventional oil. It would be at their discretion to approve or deny a warranty claim that is determined to have been caused by "incorrect" (read: non-recommended) engine oil use.

 

[Texas Woody]

This is covered in the owners manual. Synthetic is fine, as long as it meets the same specs as the conventional or better. It looks like Ram does not recommend any other viscosity of conventional oil. It would be at their discretion to approve or deny a warranty claim that is determined to have been caused by "incorrect" (read: non-recommended) engine oil use.

Yes I've read that. What I'd love to know (from a HEMI engineer or someone on the inside at FCA) is the deeper "why" they spec 5W-20 and not 0W-20, 0W-30 or even 5W-30 if it meets the Chrysler MS-6395 spec? What is it about a 0W weight in cold temps (or at startup) that is bad for this engine compared to a 5W weight? Same question goes for a 30 weight at normal engine operating temps as opposed to a 20 weight? It can't be all about fuel efficiency can it?

Just some of the crap that goes through my head on the topic of oil selection with this truck.

 

[riccnick]

Yes I've read that. What I'd love to know (from a HEMI engineer or someone on the inside at FCA) is the deeper "why" they spec 5W-20 and not 0W-20, 0W-30 or even 5W-30 if it meets the Chrysler MS-6395 spec? What is it about a 0W weight in cold temps (or at startup) that is bad for this engine compared to a 5W weight? Same question goes for a 30 weight at normal engine operating temps as opposed to a 20 weight? It can't be all about fuel efficiency can it?

Just some of the crap that goes through my head on the topic of oil selection with this truck.

Well I'm no FCA Engineer, but it essentially boils down to the lubricating properties of the engine, and what it was designed for. The Hemi has MDS, which is activated by a change in oil pressure to the lifters of the cylinders it wants to shut off. I would imagine that alone is enough reason to not want too many variables being uncontrolled in the lubrication of the internals of this engine. There could be other reasons as well.

 

[Texas Woody]

Well I'm no FCA Engineer, but it essentially boils down to the lubricating properties of the engine, and what it was designed for. The Hemi has MDS, which is activated by a change in oil pressure to the lifters of the cylinders it wants to shut off. I would imagine that alone is enough reason to not want too many variables being uncontrolled in the lubrication of the internals of this engine. There could be other reasons as well.

Fair point on the MDS operation.

 

[riccnick]

Fair point on the MDS operation.

Without knowing the true performance targets for lubricating the engine, all we can do is speculate. But that's my best guess. Consistency in the way the oil interacts with the internals of the engine would be a high priority for me if I were in charge of making sure customers don't cause themselves damage to their engines.

 

[SpeedyV]

Well I'm no FCA Engineer, but it essentially boils down to the lubricating properties of the engine, and what it was designed for. The Hemi has MDS, which is activated by a change in oil pressure to the lifters of the cylinders it wants to shut off. I would imagine that alone is enough reason to not want too many variables being uncontrolled in the lubrication of the internals of this engine. There could be other reasons as well.

Playing devil’s advocate...wouldn’t 0W-20 and 5W-20 have essentially identical characteristics when hot?

I don’t know of any reason 0W-20 couldn’t be used, but (to your point) I also don’t know what other factors are in play...so I’ll just stick to the FCA recommendations.

 

[riccnick]

Playing devil’s advocate...wouldn’t 0W-20 and 5W-20 have essentially identical characteristics when hot?

I don’t know of any reason 0W-20 couldn’t be used, but (to your point) I also don’t know what other factors are in play...so I’ll just stick to the FCA recommendations.

The 0W oil will provide better lubrication at lower temperatures than the 5w, and they will be the same at high temps as you suggested. Generally, 0w oils were at one point all synthetic, however now with synthetic blend oils, that is no longer the case. If you're running a true synthetic oil, I'm sure 0W20 would be just fine. However, I think the ambiguity intentionally favors FCA when it comes down to warranty coverage and denial in the event of an oiling related engine failure.

 

[Firebird]

I run Redline 5w30 in mine. I live in Florida, 104 degrees today, and that 20 weight junk is too thin for this heat.

 

[duke2001]

I run Redline 5w30 in mine. I live in Florida, 104 degrees today, and that 20 weight junk is too thin for this heat.

Educate us, please.First, why is “20 weight”junk? Secondly on what basis do you state it is too thin for the heat? Forgive the questions if you are pulling our chain, but if not, I am ready to learn.

 

[GerryS]

I run Redline 5w30 in mine. I live in Florida, 104 degrees today, and that 20 weight junk is too thin for this heat.

I don't think it matters what the outside temp is. If the engine is running at the same temp whether it's 104 degrees or 40 degrees outside, the outside temp is irrelevant.
If you stick with the recommended oil viscosity and oil and filter change intervals, you will not have an oil related problem with your engine that would be avoided by using a non recommended oil viscosity.

Don't buy the cheapest oil filters or oil; It's really that simple.

Those engineers that designed these engines are probably not the dullest knives in the drawer. Why try to outsmart them?

Gerry

 

[GerryS]

Aside from the owner's manual stating a recommended viscosity rating of 5W-20, what would be the downside of running 0W-20 or even a 5W-30 full synthetic in our 5.7L HEMIs so long as the oil meets the MS-6395 spec? Would Ram not honor their warranty if there were any engine issues?

Been looking at the Pennzoil Ultra Platinum offerings in anticipation my first oil change...

Thanks in advance for your thoughts.

I'm not an engineer, but I know enough to get me in trouble. I believe the 20 part of the spec is due to bearing clearances in the engine. You want good flow of oil through the bearings. If you raise the viscosity, usually the oil pressure increases. That's because the oil is thicker and doesn't flow through the bearing clearances as well. Also heats up the oil unnecessarily because you are adding pressure.

On the other end (5W vs 0W) is the cold spec. It probably doesn't matter much with the quality of oils these days, but maybe the thicker viscosity might be better on a cold start. The oil pump may push more oil because the oil is not leaking around the gears in the oil pump? I don't know.

What I do know is that if you use quality oil filters , oil in the recommended viscosity and recommended oil changes, you will be trading the truck in long before you have a lubrication issue.

Gerry

 

[cra1g]

Aside from the owner's manual stating a recommended viscosity rating of 5W-20, what would be the downside of running 0W-20 or even a 5W-30 full synthetic in our 5.7L HEMIs so long as the oil meets the MS-6395 spec? Would Ram not honor their warranty if there were any engine issues?

Been looking at the Pennzoil Ultra Platinum offerings in anticipation my first oil change...

Thanks in advance for your thoughts.

Since you can get Pennzoil Ultra Platinum in 5w20, I guess my question is why wouldn't you just do that?

 

[ForTehNguyen]

oil selection nowadays has a lot to do with squeezing every drop of mpg from the engine. Thinner oils like 0W-20 give the engine more mpg due to its lower viscosity. Also thinner oils like 0W-20 has to span all the temperature ranges of where these cars are sold so a south texas truck gets the same oil as a canada truck. It never gets that cold in the winter down here so I use a thicker oil 5W-30 which I use around our family fleet. I will use 5W-30 to get rid of my break in oil

 

[ForTehNguyen]

Educate us, please.First, why is “20 weight”junk? Secondly on what basis do you state it is too thin for the heat? Forgive the questions if you are pulling our chain, but if not, I am ready to learn.

thinner oils at higher temperatures dont protect as well, since they thin out and wont stick to the metal surface as well. Thats why when people track their sportscars they usually put in a thicker oil.

 

[SpeedyV]

thinner oils at higher temperatures dont protect as well, since they thin out and wont stick to the metal surface as well. Thats why when people track their sportscars they usually put in a thicker oil.

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The OP’s question was whether 0W-20 would work as well as 5W-20 in this application. These charts demonstrate that a 0W oil covers the full temperature range of a 5W, plus a bit more extreme cold weather performance.

There’s some debate (and it’s even been mentioned in this thread) that FCA specifies 5W-20 specifically to ensure proper MDS operation. But I’m not sure why 0W-20 would have any negative impact.

 

[freerider969]

oil selection nowadays has a lot to do with squeezing every drop of mpg from the engine. Thinner oils like 0W-20 give the engine more mpg due to its lower viscosity. Also thinner oils like 0W-20 has to span all the temperature ranges of where these cars are sold so a south texas truck gets the same oil as a canada truck. It never gets that cold in the winter down here so I use a thicker oil 5W-30 which I use around our family fleet. I will use 5W-30 to get rid of my break in oil

I used Amsoil 0W30 back in late 1998 when that first came out, I put it in my 1998 Ford Mustang GT. I saw a 2 mpg increase but at first the oil light would come on for a couple of seconds and turn off. I never had any issues with the engine but I do see where in the manual FCA recommends 5W20. I will most likely stick to 5W20 but I highly doubt any harm would come out of using 5W30 especially in our Texas heat.

 

[rceagle1a]

Yes I've read that. What I'd love to know (from a HEMI engineer or someone on the inside at FCA) is the deeper "why" they spec 5W-20 and not 0W-20, 0W-30 or even 5W-30 if it meets the Chrysler MS-6395 spec? What is it about a 0W weight in cold temps (or at startup) that is bad for this engine compared to a 5W weight? Same question goes for a 30 weight at normal engine operating temps as opposed to a 20 weight? It can't be all about fuel efficiency can it?

Just some of the crap that goes through my head on the topic of oil selection with this truck.

Oem’s love the 0/5-20 weight oils because they can sell you major engine parts just out of warranty. If my cam ever fails it’s BYE BYE mds and hello 10w30 oil in winter and 10w40 in summer. But until warranty is gone I’ll play by the rules.

 

[Willwork4truck]

The “oil wars” will go on and on but the post above is what Id follow. During your factory or extended warranty, use what will keep you covered. People have been denied for less, and theres threads about it.

 

[duke2001]