15w/50 in place of 0w/20 WHY?

[Swifty]

I have not posted here to much I mostly try to read and learn, but I am currently having an argument with someone who insists on using M1-15w/50 in a vehicle spec'd for 0w20 (2013 civic si k24)and wanted to know why one would do this. I'm curious and want to understand! Supposedly this person has 30 plus years in engine R&D(which is oil related)including small engines, weed eaters diesel applications etc etc. He lives in a hot climate and all I could get out of him was friction equals wear.

I don't think for one this vehicle would gain anything protection wise from using a 50 weight oil that you couldn't get out of a 30 weight oil or a 20 weight for that matter. If anything I think you would be contributing to increased heat using the higher viscosity and possibly starving critical parts of oil in this application.

If you did a UOA of the 15w/50 and then one of a 10w30 for example in this car I cannot imagine there would be any measurable difference in wear using the 30 weight.

Am I missing something here? I appreciate your input.

Thanks Brian

 

[SwampSurvivor]

There is ZERO reason to run 15w-50 in the place of 0w-20 except for complete ignorance - especially in an engine designed for 0w-20.

Some people believe that you need to run the thickest oil possible and change every 1500 miles in order to get the engine to last.

 

[Rand]

if they were tracking it for extended periods I'd recommend a 30wt oil,or an oil temp gauge. 50wt is just stupid in that application.

 

[Swifty]

His words.

Friction = wear and is not a linear function of oil viscosity, load or rpm see Stribeck x axis. 2 SAE papers of the year so wth do they or I know?

The other issue is how does he know what the engineers spec'd for this car? It certainly wasn't a 50 weight oil.

I probably should have posted this in PCMO for passenger cars.

 

[eljefino]

I wouldn't engage this person except to find out why he stops at 15w50 and doesn't go for the 70 weight harley oil.

 

[SwampSurvivor]

Originally Posted By: eljefino
I wouldn't engage this person except to find out why he stops at 15w50 and doesn't go for the 70 weight harley oil.


Shoot, I'd recommend running 85w-140.

(Yes, I know gear oil is rated differently, but it ads to the thickness side haha)

 

[Swifty]

Now these two last post made me laugh and Eljefino you are correct. I shouldn't even engage in a conversation with this individual but it is kind of fun. I want to see what kind of data he can provide to support his use.

 

[CarbonSteel]

Originally Posted By: Swifty
Now these two last post made me laugh and Eljefino you are correct. I shouldn't even engage in a conversation with this individual but it is kind of fun. I want to see what kind of data he can provide to support his use.

None for it does not exist - but he already knows more than the engineers who designed the engine so for him to explain his rationale is "beneath" him and would be a nuisance. His go to statement is likely "because".

 

[HTSS_TR]

Tell him that BMW recommends 10W60 for some M3 and M5, therefore using it will increase engine power close to BMW M series, also it protects engine like no other grades.

 

[bdcardinal]

Never argue with an idiot, they bring you down to their level and beat you with experience.

 

[901Memphis]

Unless your oil temperatures soar and pressure drops, then there is no need to skip the 0w20. At most if pressure drops you could go up to a 5w30 synthetic which is used in many racing applications.

 

[SilverC6]

You can't fix stupid.

 

[Swifty]

Originally Posted By: SilverC6
You can't fix stupid.


I use this quote a lot myself and it certainly applies here.

Gotta love Ron White!

 

[SilverC6]

Ron could read the phone book and make you laugh.

Great comedian.

 

[JHZR2]

There is a reason why we have EP and AW adds, and why we see a minima in wear on the Stribeck curve when we hit the point between mixed film and hydrodynamic lubrication. Cavitation may not necessarily be a continuous occurrence either, as the fluid velocity transitions into steady flow, any shear-induced thinning occurs, there is local heating, viscosity decreases, etc. I do not believe that this is an issue to anyone but the user of the most exotic or race-type engine, and even then it may not be a practical issue for all intents and purposes.

Now, I agree that oil is dynamic, especially over the OCI and conditions incurred. That's for sure. But IMO that has also been part of the consideration set in engineering and specifying a lubricant to do a job. One of the comments when people were transitioning from 5w30 to 5w-20 oils was that the 30wt oils often sheared down into a heavy 20, so people HAVE been running lighter oils for a long time and not known it. The intent of that comment was to show that if the 5w-20 oils coming on market are shear-stable, then it is no different than what ran in most sumps for the last 1500+ miles anyway for years and years past.

UOA is no newfangled technique. Engine manufacturers and lubrication engineers know what an oil will look like after a relevant amount of shearing, heating, oxidation, etc. These are all knobs which can be turned (look at older versions of M1 0w-40 which competed shearing with oxidation to maintain a 40wt A3 oil) as part of the lube design. The engine builders know what they need to know - Viscosity, rotational speed and load. From Noria:

This stuff is easily calculated for designs and across the lifecycle of the engine and lubricant. There is sufficient variability in lube options that the "right one" can be specified or a specification can be written to make it work.

Example: is 10w-60 REALLY necessary for an M engine? Maybe really a 50wt is necessary, but given the characteristics of service interval and available lubricants, the 10w-60 was selected to provide the maximum "time at rated condition" (which is what engineering stuff is really about) to provide "design life at rated condition". That is the end game and goal. To do that, as cheaply as possible, with just enough overdesign to ensure optimal MTBF/MTBO and customer satisfaction without costing too much in NRE, parts, labor, etc.

I think that for the most part, statistically significant information has suitably indicated a non-issue using the specified lube for the specified interval in ones' engine. That doesnt mean to pack up shop and go home, but it does generally mean that using the recommendation is a fair approach that has been successful, and optimization, if any, is generally done more for sport/hobby than to see practical longevity improvements.

 

[kmrcstintn]

since he likes running thick lubrication...

1 bottle of Lucas Oil Stabilizer, 5 bottles of STP Oil Treatment, 1 bottle Bardhal No Smoke, and 1 bottle of Pennzoil 25w-50 racing oil for good measure...

 

[Swifty]

So there is no gain in using a significantly heavier viscosity in this particular application when a 20 weight is recommended. IF he had shown he was having a significant shearing issue using a 20 weight oil I could see moving to a 30 weight. But a 50 weight in a k24. May do more harm than good over time.

 

[jrustles]

Originally Posted By: Swifty
But a 50 weight in a k24. May do more harm than good over time.
It surely would not increase wear, no matter what kind of 'cold start' arguments come about, I'd put money on that, but it wouldn't do anything than possibly waste a discernible amount of fuel and rob him of HP to the wheels. Those engines need to rev to make power, not punish the crankpins with torque. Try to get old pal there to understand the difference in lubrication needs between different engines.

The only thing I might be concerned about is galling of the camshaft with extended high RPM duty, ie tracking etc. but not likely much concerned.

 

[SwampSurvivor]

Originally Posted By: kmrcstintn
since he likes running thick lubrication...

1 bottle of Lucas Oil Stabilizer, 5 bottles of STP Oil Treatment, 1 bottle Bardhal No Smoke, and 1 bottle of Pennzoil 25w-50 racing oil for good measure...

That sounds like it would work great!

He ought to be able to run that thing wide open all day haha

 

[carmine_ricca]

I have a 1999 Dodge Neon, DOHC, I bought this brand new, In the winter I either used 10w30 or 5w30 but in the summer I always used 20w-50. The car now has 147000 miles on it and uses no oil and enginge still has the same acceleration and when it was new. The winter time needs quick lubrication, but in the summer it needs the 20-50 because of lubrication. It provides a thicker oil film between moving parts,