Oil "Myths" that are actually True?

[Audi Junkie]

You know when someone new comes to the forum to verify if a "myth" is true...are there any "true" myths?

Synthetic causes leaks.

Dino causes sludge.

0w oil is like water /"too thin".

20 weight will destroy engines.

You can't mix synthetic and conventional or use dino after switching to synthetic.

Low ZDDP kills engines.

Synthetic is "better" for your engine.

Synthetic is more slippery than dino.

Synthetic reduces wear.

Thicker is better.

WalMart sells inferior oils.

Following the oem manual guarantees long engine life.

Boutique oils offer unparalleled performance.

 

[ARCOgraphite]

MYTH-
Used oil will cause less engine wear than new. I lost the link to the study - think it was GM and ????

 

[Audi Junkie]

3MP?

 

[BeanCounter]

Isn't that an oxymoron, like "jumbo shrimp"?

I'm just picking, but I somewhat understand what you're saying. The closest thing I can think of are misconceptions that may be partly true in result, but the reasoning behind it is skewed. This may fall under false "myth" though so...I dunno...

EDIT: I think you mentioned a few in your revision of the first post. Maybe true, but not for the conceived reasoning.

 

[Quattro Pete]

Originally Posted By: Audi Junkie
Dino causes sludge.

Potentially, it could, if you never change it.

 

[c3po]

Originally Posted By: ARCOgraphite
MYTH-
Used oil will cause less engine wear than new. I lost the link to the study - think it was GM and ????


FORD!

 

[Trav]

Some of the myths could be true in certain situations.

 

[Nick R]

Synthetic causes leaks: Generally False, but in some circumstances can clean gunk out of old seals and then leak.

Dino causes sludge: Doesn't CAUSE sludge, but can be more prone to it over long OCI and hard use.

0w oil is like water /"too thin": Complete fallacy.

20 weight will destroy engines: Nother fallacy.

You can't mix synthetic and conventional or use dino after switching to synthetic: Untrue

Low ZDDP kills engines: Generally untrue, but can prove to be troublesome in engines that have flat tappets and very high valve spring pressures.

Synthetic is "better" for your engine: Depends on the specific application and circumstances.

Synthetic is more slippery than dino: Depends. Group IV base stocks aren't as inherently "slippery" as Group II dino, but Group III is pretty close to II.

Synthetic reduces wear: Depends on the specific application and circumstances.

Thicker is better: Generally no, in some cases yes. Sports cars and high performance engines/diesels come to mind.

WalMart sells inferior oils: Couldn't be further from the truth.

Following the oem manual guarantees long engine life: Not necessarily, as shown by the number of people with extremely high mileage engines running OCI in excess of 5K miles.

Boutique oils offer unparalleled performance.: Sometimes, in certain circumstances, and certain products Redline comes to mind.

 

[BeanCounter]

Originally Posted By: rudolphna

Dino causes sludge: Doesn't CAUSE sludge, but can be more prone to it over long OCI and hard use.


I guess this depends what perspective you are viewing it at, but I'll agree with you here for the heck of it.

 

[Panzerman]

How about 10w30 is to thick for a engine to pump in temps below 32 F. Ever since this rage came about thin oils, no one can seem to imagine how people started their cars in the past with straight 30 wt oil. And how come 0w20 is fine for a car speced for 5w20, but 5w40 is considered insanely thick. Dont we go by the "5" number for cold temps and the "40" in heat. 10w30 seems to me, to be splitting the difference. I have never seen oil freeze solid by the way, that includes straight 40 wt. left outside in drums in temps well below 0.

 

[BeanCounter]

Originally Posted By: Panzerman
Dont we go by the "5" number for cold temps and the "40" in heat.


Yes, it is still a 40 weight oil, but it can flow like a 5 weight when it is cold. This is also why a 5w-X can seem to leak, etc., more than a 10w-X when it has been sitting at a colder temperature.

 

[JCCADILLACMOBILE]

I want to knwo how someone can say that "Oil getting Dirty does not mean it is time to change it" is not a Myth (Double negatives removed: "When Oil is Dirty, it does not need to be changed."
Also, i knwo my parents DID use 10W-40 year Round. IN ORANGE COUNTY NY. 10 number in Winter means that when it gets to like 20 degrees, or more like 10.. it will crank? <-- Tecaco Havoline Supreme, Conventional OIL..

 

[qship1996]

Group 3 is NOT synthetic.....it is processed petroleum{except in the USA we consider it synthetic, thanks to Castrol}

 

[Zedhed]

Forgot one:

Myth:

Don't use synthetic on a new engine. It won't break-in properly .

Reality:

Many new vehicles come with Mobil 1 as factory fill.

 

[JCCADILLACMOBILE]

Originally Posted By: qship1996
Group 3 is NOT synthetic.....it is processed petroleum{except in the USA we consider it synthetic, thanks to Castrol}


I KNEW there was Controversy over Castrol calling its oil Synthetic when it wasnt!!

Now. about the Dirty Oil one (Oil dirty, time to change) - True or False?

I must admit.. I always thought:

1) "-20" oil (5w-20) Destroys engines.. Seems sso thin not sure how it wouldnt;
2) 5W oils are "Like Water" - Base oil is a 5, how can it properly Thicken? My mechanic ALWAYS loved the "20 Point Spread" of 10W...30..
3) not to mix Dino oand Synth.

 

[Panzerman]

I went to Tampa last year in with a guy that works with my wife in a newer 2000 something Dodge Caravan with 192,000 miles and it ran like a top and I asked him (naturally) what oil he used and he said Castrol GTX 20w50, every 3 to 4000 miles. Said it does not use any oil. Quiet motor. sounded Great with that amount of miles. Ill never be convinced light oil is any better or worse. I just go with 10w30 and be happy, to be in the middle of the spectrum.

 

[chevrofreak]

Originally Posted By: qship1996
Group 3 is NOT synthetic.....it is processed petroleum{except in the USA we consider it synthetic, thanks to Castrol}


What makes an oil synthetic?

 

[Tom NJ]

Good analysis!

Tom NJ

 

[JCCADILLACMOBILE]

Originally Posted By: Panzerman
I went to Tampa last year in with a guy that works with my wife in a newer 2000 something Dodge Caravan with 192,000 miles and it ran like a top and I asked him (naturally) what oil he used and he said Castrol GTX 20w50, every 3 to 4000 miles. Said it does not use any oil. Quiet motor. sounded Great with that amount of miles. Ill never be convinced light oil is any better or worse. I just go with 10w30 and be happy, to be in the middle of the spectrum.


Did he also run 100% Water in the cooling system? Some people do, i know not why.. (Antifreeze stops Rust right?)

 

[ARCOgraphite]

Originally Posted By: chevrofreak
Originally Posted By: qship1996
Group 3 is NOT synthetic.....it is processed petroleum{except in the USA we consider it synthetic, thanks to Castrol}


What makes an oil synthetic?
Did not SAE pull their "scientific" definition? Are we definitionless?