5w20 vs 5w30

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Originally Posted By: ChadW
lool, i hope there are other people on here smarter than u are


He could do a four page write up on the many factors that would be needed to accurately answer your question. But in general 5W-20 protects just as well as 5W-30 and in some applications better in others not as good.


That being said I own a pickup that I often tow 4000LBS and have another 700-900LBS in the bed along with my family of 5 so add another 650LBS and I drive often in the desert southwest and up and down the west coast of California on camping trips. Also for "fun" I will go off roading on occasion. Conventional 5W-20 protects my engine just fine. But other will feel that is too thin and put in 20W-50 because thicker is "better".
 
CHAD-
Define "protects". Ask a smarter question and get a well considered answer.
The short, absolute answer though is NO. It has a somewhat smaller margin of safety than a ILSAC 5w30 due to lower HTHS. But ILSAC 5w30 is also a poor lubricant for severe conditions/use.
Please note that "adequate" oil pressure is NOT the final determinator of margin of safety. If some "respected" member states so over and over here doesnt make it correct. It a basic misundertanding and knowledeg of lubricants. Adequate Viscosity trumps all.
Go ahead and run an ILSAC 5w20 in a v8 detroit diesel and see how long that lasts - right there is your calculus and your extrapolation and your proof.
 
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Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.
 
Originally Posted By: ChadW
Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.


your question was extremely vague. therefore you will get vague answers.

also I see you are new here.. might want to read the forum rules this isnt your LOLs typical forum

its fairly but strictly moderated.


at the very least you need to tell us what application you are talking about.

if its a 2001-2009 ford ranger 4.0 the answer would be no..

if its a 2011 toyota corolla... the answer would be probably.

it would also depend on particular brands and types of 5w20 and 5w30

some 5w20 might protect better than 5w30 in an application etc. Your question was about as vague as

"what are the best tires" not enough information leads to vague and unsatisfying answers.

and I hope you arent trolling because I wasted 3min typing this :p
 
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Originally Posted By: ChadW
Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.


Problem is you use the specific grade for your application, there is no "one oil fits all" which it seams you are looking for.
 
Originally Posted By: ChadW
Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.


You asked a vague question. Now give us some details on what engine you are trying to protect. If you ask a open ended question you will receive open ended answers. Like Arco said that if you put a 5W-20 in a nice V8 diesel you will get results that is less than to be desired. If you put 5W-20 in my gasoline V8 that is spec'd for 5W-20 it will run for many of hundreds of thousands of miles just fine. I see very little difference in a PCMO 5W-20 and a PCMO 5W-30 that is API SN certified. In fact after about 1,000 miles of use a 5W-30 is a 5W-20 due to shearing.
 
Originally Posted By: ChadW
Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.



Whats with the TUDE....DUDE??
grin.gif
 
Last 5 vehicles my wife and I have owned call for 5W20 both in the owners manual and oil filler cap.

Use 5W20 Synthetic and no issues. Long hot Summers here as we are just a few miles from the Florida line. City uses 5W20 oil in their Ford Police Cars and you know what kind of abuse they receive with long idling, WOT, etc.

If you want an extra measure of protection why not use a 5W20 synthetic?
 
Rand, read the rules again and don't see where any violations were madeLOL. K, I see your point about what type of application. How bout a 98 ram 1500 with 360 magnum. Also an 03 Town and country 3.3. These applications are usually 10w30 or 5w30 in cold times. I understand that 5w20 would be thinner on start up, and i would probly get better mileage and better oil flow, but what about when at operating temp? Is the 20 gonna "protect" as well as a 30? That's pretty much what i'm getting at.
 
Dave, so after 1000 miles of use, what is a 5w20 due to shearing?
 
Shearing would depend on the engine application. 5W30 has more VI hence a greater chance of shearing.

This would require an engineering study for specific application and would beyond the scope of information you would find here.
 
Originally Posted By: ChadW
Rand, read the rules again and don't see where any violations were madeLOL. K, I see your point about what type of application. How bout a 98 ram 1500 with 360 magnum. Also an 03 Town and country 3.3. These applications are usually 10w30 or 5w30 in cold times. I understand that 5w20 would be thinner on start up, and i would probly get better mileage and better oil flow, but what about when at operating temp? Is the 20 gonna "protect" as well as a 30? That's pretty much what i'm getting at.


If you are just comparing just straight at operating temperature viscosity the short answer is no. But with all the oil recommendations revisions that Chrysler has been making on the 3.3 engine family along with the 5.9 V8 what happens as PCMO quality improves Chrysler and other manufactures recommend lower and lower viscosity until the point we are today. Just by going on the vintage of your motors I would just use 5W-30 for both engines if you do not have consumption issues and call it a day.
 
Originally Posted By: ChadW
Dave, so after 1000 miles of use, what is a 5w20 due to shearing?



Most multigrade engine oils made from mineral oil contain special types of additives, called Viscosity Index Improvers (VI Improvers). These molecules are larger in size than the oil molecules and are used in small amounts to give better low temperature viscosity while still maintaining an appropriate level of viscosity at operating temperature. However, depending on the size of the VI Improver molecules, as the oil passes through the engine, some of these larger molecules are permanently broken down into smaller molecules that are less effective in contributing to viscosity.

Molecular shearing of lubricating oils typically occurs in very tight spaces between moving parts that are in close proximity to one another. Bearings and ring faces are classic examples of where engine oil shearing can occur. Polymer coils also react to changes in shear or flow-rate in the oil.

When the shear stress is removed, the distorted coil resumes its original spherical shape and the oil’s viscosity returns to its original value. This shear thinning is therefore termed “temporary viscosity loss.”

Under more extreme (very high) shear conditions, the coil can be pulled apart and polymer chain broken into two smaller chains. These two smaller chains have less impact on the oil’s viscosity than a single large chain, so the viscosity falls in this case as well, especially since the chains also align in the direction of flow. When the shear is removed, the broken polymer chain cannot re-form into the single large chain because the coil has been physically and chemically changed. Consequently, the oil’s viscosity does not return to its original value, but remains at a lower viscosity. This is known as “permanent viscosity loss.”



Also I will add that I have studied many many 5W-30 UOA's and it is well over 90% of applications that a 5W-30 will shear into the 20 viscosity range. Red Line oils do not shear into this range very often even a engine family like Duratec that is "easy" on oils 5W-30's will shear into the 20 viscosity range more often than not.
 
Some viscosity loss can occur if the oil has Viscosity Improvers in it, but a 5w20 will remain a 20-weight. The vast majority of 20-weight oils are in the upper third of the viscosity range and will stay in grade under use.

But if your engine calls for a 5w30 in the owner's manual, I recommend that you use 5w30.
 
Originally Posted By: ChadW
So does a 5w20 shear down?


Most of the time yes but I have not seen it shear out of the 20 viscosity range. The theory is that it take less viscosity improvers(VI) to obtain the 5W rating for a 20 viscosity versus a 30 viscosity oil. So with less VI needed to formulate a muti-grade oil i.e.(5W-20,5W-30) the oil that has less VI is less prone to shearing. This is a inherent advantage to synthetic oils that synthetic oils need less VI to obtain the desired viscosity range so therefore are a little less likely to shear and more likely to stay in grade.
 
Originally Posted By: ChadW
So does a 5w20 shear down?


Yes, but generally not out of it's acceptable range without fuel dillution.

From here you can either take a few minutes to look in the UOA section, or you can read the motor oil 101. But there's no point to asking basic questions if you haven't done either of those.
 
Originally Posted By: Rand
Originally Posted By: ChadW
Why do we put oil in our engines? To PROTECT it. Right? To prolong the life of the engine. ????? You don't have to be a scientist to know that. It looks like a-lot of people here are pretty vague. But some at least wing it and try to give a halfway reasonable answer.




and I hope you arent trolling because I wasted 3min typing this :p



you're a slow typer
 
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