5W-20 vs. 5W-30

ThePresence

Elite Member
Nov 19, 2001
27,727
16
81
My car is a 2004 Acura TL.
The manual says to only use 5W-20.
The oil cap too says 5W-20 only.
A mechanic told me he recommends using 5W-30.
He says the weight difference is marginal at best, and it's better for the engine.
To me it would seem that Acura would tell you to use what's best for the engine.

Any thoughts?
 

franksta

Golden Member
Jun 6, 2001
1,967
6
81
I would use what the manual says. The manual for my truck recommends 5W-30 however other vehicles with the same motor (perhaps slightly different?) recommend 5W-20. (F-150 vs. Crown Vic both with 4.6L) I don't know why they would recommend different oils.
 

desy

Diamond Member
Jan 13, 2000
5,442
212
106
Acura suggest 5-20 because it lowers their fleet averages by like 1/2 mile to a mile across th whole fleet to meet CAFE standards
You would never see any difference in using either, If you are someplace hot I'd use the
5-30
 

BassBomb

Diamond Member
Nov 25, 2005
8,390
1
81
Use what is reccomended, I have a Civic takes the same oil. Whenever I get it oil changed they always try to put 5W30 in but I make sure they don't.

You are fine if you do it for one change once in a while (the manual says it is an OK alternative) but not mroe than once in a row
 

woodie1

Diamond Member
Mar 7, 2000
5,947
0
0
I have an Acura too and would never use anything other than the specified 5W-20 except in an emergency. If it is hot where you live and 5W-30 is okay then why not 10W-30 or 10W-40.
 

StageLeft

No Lifer
Sep 29, 2000
70,150
5
0
Go with the manual, they don't arbitrarily come up with the figures regardless of what some generic chart tells you about weight and temperatures that your engine should never be operating at anyway.
 

chucky2

Lifer
Dec 9, 1999
10,018
37
91
In vehicles where the factory calls for xW-20, and there is no fuel dilution or coolant contamination, an xW-20 is all that's needed.

If you want to switch to anything, switch to a 0W-20.

There are probably 100's if not 1000's of UOA's on BITOG at this point that show xW-20 oils are just fine in engines that call for them. You need to understand that mechanics turn wrenchs, they aren't lubrication engineers or tribologists...take what they say with grains - and sometimes bags - of salt.

Chuck
 

mooseracing

Golden Member
Mar 9, 2006
1,711
0
0
Originally posted by: chucky2
You need to understand that mechanics turn wrenchs, they aren't lubrication engineers or tribologists...take what they say with grains - and sometimes bags - of salt.

Chuck

That can be turned both ways. The engineers don't spend years inside of thousands of engines. They just do supposed life tests in short increments. Unlike the mechanics who see first hand what happens inside the engine when the viscosities change.

 

chucky2

Lifer
Dec 9, 1999
10,018
37
91
Originally posted by: mooseracing
Originally posted by: chucky2
You need to understand that mechanics turn wrenchs, they aren't lubrication engineers or tribologists...take what they say with grains - and sometimes bags - of salt.

Chuck

That can be turned both ways. The engineers don't spend years inside of thousands of engines. They just do supposed life tests in short increments. Unlike the mechanics who see first hand what happens inside the engine when the viscosities change.

Yes, it can be turned both ways, but the problem is the engineers have 1000's of hours on engine test stands in controlled environments with calibrated equipment, running controlled tests and logging data and then analyzing it.

The mechanics have none of that, have no training/knowledge to even do that, so they just guess, which anyone can do, wrench turner or not.

I'll take the engineers opinion myself...

Chuck
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Your mechanic may be just recommending what he has in bulk. 5W-20 is almost never in bulk form AFAIK in any lube place outside perhaps the dealerships that call for it.
 

Vette73

Lifer
Jul 5, 2000
21,503
9
0
Little to no difference. There are some 5w30's that are on the low end and some 5w20's that are on the high end so much that they are about the same.


This has NOTHING to do with engineers testing to see if it will hold up longer, make the engine better, etc... its ONLY about gas milage. The same cars/engines in other countries call for 5w30. Its only the US that has the big 5w20 push. CAFE standards.

So use which ever is easier to find and cheaper.
 

SoulAssassin

Diamond Member
Feb 1, 2001
6,135
2
0
--- Original Message -----
From: Oil Specialist
To: joe
Sent: Sunday, June 22, 2008 8:04 PM
Subject: Re: 0w 20 vs 5w 30

Hi Joe, the 0W-30 and 5W-30 consumption rate are pretty close, if not the same; virtually no difference. In fact the SSO is a superior chemistry.

I always sell a 30W (SSO, ATM, ASL, HDD) vs the 20W unless a customer is adament about using the 20W:

Here's my write up:

The 5W-20 recommended is strictly a move on the automakers part to get better CAFE #'s that they can report to the Federal Govt. I am very familar with the reasoning behind this by the auto manufacturers. It basically saves about 0.06 MPG, which is nothing to the consumer but multipled by millions of vehicles it alows them to meet the strict and tightening EPA CAFE regulations and by doing that they can sell more profitable SUV's and have the CAFE #'s offset by the cars and smaller vehicles that get better fuel economy. It's all a numbers game.

Recently several automotive manufacturers started using 5W-20 or 0W-20 motor oil as a factory fill. Most consumers have many questions about this "new" oil and why after all these years specifying a 5W-30 that they would make the change to 5W-20 or 0W-20. First I must explain that 5W-20 ( or 0W-20) is not a new viscosity motor. 5W-20 has been around since the early 1970's, but not used by consumers or marketed to consumers by manufacturers, until recently.

My research has uncovered the following from a SAE technical paper written by Mobil Research and Development Corp. in 1975 (o): "Research Oil 5 (RO-5) is a conventional 5W-20 viscosity mineral oil product containing an API SE quality additive treatment, but that it may be deficient in some API SE engine performance requirements. RO-6 is also a 5W-20 viscosity and API quality SE but utilizes all-ester (synthetic) base stock components. Adequate wear protection with conventional 5W-20 viscosity mineral oils has been difficult to achieve under moderate and high temperature operating conditions." Mobil's new 5W-20 synthetic formulation, XRN 1669 "has been evaluated in both laboratory and field tests to determine its antiwear performance. In all cases, wear protection equal to or better than premium API SE quality SAE 10W-40 mineral oils has been provided by this experimental formulation"

Now, keep in mind that this is from about 30+ years ago. My intent here is to show that 5W-20 is not a new viscosity of oil. It just never became widely used. The most popular motor oils back in that era for automotive use were typically 10W-40 and in later years 10W-30 and 5W-30. What this data indicated is that a 5W-20 petroleum oil provides adequate engine protection under normal operating conditions, but does not compare to a premium quality 5W-20 synthetic in moderate and high temperature operating conditions. The new 5W-20 oils of today are formulated to meet the latest API SL performance specifications and are perfectly suitable for use in your new vehicle that specifies 5W-20, however my personal opinion is that there are superior oils to use that not only meet the 5W-20 performance specifications, but also exceed them.

Here is a brief discussion of some of the most common questions consumers have regarding the 5W-20 motor oil that is specified for their new vehicle.
Question: Do I really need to use 5W-20 or 0W-20 oil?

Answer: You certainly can if you choose to, however there are also other viscosities you can use such as 5W-30 and 0W-30 that also meet manufacturers and API specifications. One of the main reasons 5W-20 or 0W-20 was specified for your engine is to increase the CAFE (Corporate Average Fuel Economy) reported to the Federal Government. CAFE is the combined average fuel economy of all of a vehicle manufacturers product line. Minimum CAFE levels are specified by the Federal Government. In order for a vehicle manufacturer to continue selling profitable large trucks and SUV's, which typically have poor fuel mileage ratings, as compared to smaller cars, and still meet mandated CAFE requirements, they must also sell enough of the smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles. The change to a 5W-20 or 0W-20 oil will allow a manufacturers overall CAFE to increase by a very small amount, typically in the tenths of a mile per gallon range. 5W-20 and 0W-20 oil is a lighter viscosity than a 5W-30 oil and therefore has less internal engine frictional losses, or less drag on the crankshaft, pistons and valve train, which in turn promotes increased fuel economy. This increased fuel economy is virtually undetectable to the average motorist without the use of specialized engine monitoring and testing equipment under strictly controlled test track driving when compared to a 5W-30, 10W-30 or a 0W-30 viscosity motor oil. Note that certain specific vehicles, such as those with cylinders that selectively cut out to save energy, typically specify a 5W-20 or 0W-20 and for those vehicles it is best to use the viscosity recommended by the manufacturer.

Question: Could using a 5W-30, 10W-30, 0W-30 or even a 10W-40, oil in my vehicle which recommends a 5W-20 oil void my new car warranty?

Answer: Vehicle manufacturers recommend using motor oils meeting certain viscosity grades and American Petroleum Institute service requirements. Whether a motor oil is a 0W-20, 5W-20, 0W-30, 5W-30, 10W-30 or 10W-40 or even a synthetic vs. a petroleum based oil will not affect warranty coverage. The manufacturer is required by Federal Law to cover all equipment failures it would normally cover as long as the oil meets API service requirements and specifications and was not the cause of failure. In addition, the Federally mandated Magnuson - Moss Act states that a manufacturer may not require a specific brand or type of aftermarket product unless it is provided free of charge. If your dealership continues to tell you that you must use 5W-20 or 0W-20 motor oil and or/ a specific brand of 5W-20 or 0W-20 motor oil (and will not provide it free of charge), then ask them to put it in writing and then contact an attorney. Their position is inaccurate, and, in fact violates existing law.
Additionally, if there is ever a question of whether or not a particular motor oil was the cause of an engine failure make sure to get a sample of the used oil in a clean bottle, typically 6 oz. minimum. The oil can then be sent to an independent ASTM certified testing lab for analysis. This is standard procedure for most commercial vehicles, trucking, construction/excavation and fleet companies and there are many certified test labs all over the country. Remember, a knowledgeable and informed consumer is your best defense against being taken advantage of by a car dealership service center.

Question: My car dealership service center states that I must use 5W-20 or 0W-20 because the oil passages inside my engine are smaller and a higher viscosity oil will not properly flow through them. Is this a true statement?

Answer: That is ridiculous to assume that a manufacturer would purposely make the oil galleys and passages smaller. There is no technical or cost/performance benefit to doing this in reference to recommending a 20W motor oil over a 30W motor oil. My inspection of oil galleys, pistons, bearings, crankshafts, oil pumps and passages from pre-5W-20 and 0W-20 recommended oil engines to the same size and brand of engines that now specify 5W-20 or 0W-20 indicate there are no measurable differences in the oil passages in these components.

For those consumers that desire to use a 5W-20 oil, AMSOIL INC., does manufacture an excellent extended drain interval 5W-20 synthetic motor oil, called XL Synthetic Oil in 5W-20 viscosity. It is a 7,500 mile/6-month motor oil (or longer if you have an electronic oil life monitoring system). AMSOIL's 5W-20 synthetic motor oil provides outstanding wear protection and increased power, performance and fuel economy in high and low temperatures and also meets and exceeds the manufacturer's specifications. AMSOIL also offers a a 25,000 mile/1-year change interval 0W-20 that is an excellent choice.

My recommendation is for even better performance and protection to use AMSOIL's Signature Series 0W-30 synthetic motor oil. This is the top performing AMSOIL Synthetic Motor Oil for gasoline powered light trucks and passenger cars. It uses race-proven technology and provides unsurpassed fuel efficiency and superior wear protection than other conventional and synthetic motor oils. It is a 35,000 mile/1-year change interval motor oil. Use it in conjunction with AMSOIL's Absolute Efficiency Oil Filter's that specifies a change interval of 25,000 miles/1-year, whichever comes first under normal service conditions. AMSOIL also offers 5W-30. 10W-30 and 10W-40 Synthetic Motor Oils with a change interval specification of 25,000 miles/1-year.

Best Regards,

Dave Mann
Lubrication Specialist - Truck/Automotive Engineer
Society of Automotive Engineers Professional Member
Performance Oil Technology, L.L.C.
Traverse City, MI 49686
Business Mailing Address:
P.O. Box 215
Acme, MI 49610-0215
 

Pacfanweb

Lifer
Jan 2, 2000
13,154
58
91
Cliff notes of above: 5w20 is used to help with fuel economy, not because there has been some mystical breakthrough and the engines require it.

In Japan, unless something's changed in the last year, they recommend 5w30 for the same Hondas that the American owner's manual specifies 5w20.

You can use them interchangeably, there isn't really a dime's worth of difference in the two. On a manufacturer-wide basis, there might be, but from an individual owner's standpoint, there isn't.
 

thecritic

Senior member
Sep 5, 2004
470
0
0
Definitely use 5w-20 if the car is still covered by a warranty. Either one will work fine, but I personally see no reason to use 5w-30 unless I could obtain it for a much lower price than 5w-20.
 

chucky2

Lifer
Dec 9, 1999
10,018
37
91
It'd help if the data wasn't based on dino oils from 1975...dino oils have come just a little way since then...

Again: There is zero reason to use a xW-30 oil in an engine spec'd for xW-20, unless you have high fuel dilute or water contamination. None. Zilch. Nada.

There are even xW-20 UOA's on Excursion's with Ford's V-10 gasser, loaded down and towing, through TX summer heat, and the UOA came back fine.. If the lube didn't fail there, it's not going to fail in your TL.

Unless you have stash of xW-30 you want to use up, or you somehow get xW-30 free/crazy reduced price, then save some gas over the life of your ride and use a xW-20. You'll probably even notice a little bit quicker rev'ing of the engine.

Chuck
 

Zenmervolt

Elite member
Oct 22, 2000
24,512
22
81
Originally posted by: chucky2
You'll probably even notice a little bit quicker rev'ing of the engine.

You may indeed notice this. It won't actually be there in reality, but it's possible that people will notice it. After all, some people notice improvement from fuel line magnets.

5w20 and 5w30 are essentially interchangeable. It's not possible for 5w30 to cause problems in engines that specify 5w20. 5w20 can also be more difficult to find at a local auto parts store (though this has improved significantly so it shouldn't be an issue any longer), so if you can't find 5w20, 5w30 will be perfectly fine.

As always, I do not recommend mixing two viscosities.

ZV
 

Thump553

Lifer
Jun 2, 2000
12,824
2,613
136
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.
 

Vette73

Lifer
Jul 5, 2000
21,503
9
0
Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

Please tell me how 5w30 would cause a motor that came with 5w20 to go bad?


Are some of you that dumb? There is little to no diff. in 5w20 and 5w30. Its only done for CAFE standards in the US so they don;t have to pay as much on fees/taxs/etc... tied to CAFE. Same cars/engines that call for 5w20 in the US get 5w30 around the world.
 

mooseracing

Golden Member
Mar 9, 2006
1,711
0
0
Originally posted by: Marlin1975
Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.

Please tell me how 5w30 would cause a motor that came with 5w20 to go bad?


Are some of you that dumb? There is little to no diff. in 5w20 and 5w30. Its only done for CAFE standards in the US so they don;t have to pay as much on fees/taxs/etc... tied to CAFE. Same cars/engines that call for 5w20 in the US get 5w30 around the world.

Depending on how the engine was built it could make a difference. I doubt any High volume car coming off an assembly line would be effectd by it though.





Originally posted by: chucky2
Originally posted by: mooseracing
Originally posted by: chucky2
You need to understand that mechanics turn wrenchs, they aren't lubrication engineers or tribologists...take what they say with grains - and sometimes bags - of salt.

Chuck

That can be turned both ways. The engineers don't spend years inside of thousands of engines. They just do supposed life tests in short increments. Unlike the mechanics who see first hand what happens inside the engine when the viscosities change.

Yes, it can be turned both ways, but the problem is the engineers have 1000's of hours on engine test stands in controlled environments with calibrated equipment, running controlled tests and logging data and then analyzing it.

The mechanics have none of that, have no training/knowledge to even do that, so they just guess, which anyone can do, wrench turner or not.

I'll take the engineers opinion myself...

Chuck

Controlled tests aren't worth a whole lot in the real world. Controled test also add to more warranty claims, thats why so many manufactures drive their vehicles over 100k miles before they are released. If it's something new that hasn't seen the market I would beleive the engineer until I had taken a look inside. Once I browsed inside the engine and saw the damage it becomes obvious what it is from.
 

Pacfanweb

Lifer
Jan 2, 2000
13,154
58
91
Originally posted by: Thump553
Suppose something goes wrong with the engine because of the oil-who would you rather look to pay for replacing the engine, Honda or your local mechanic?

I also strongly suspect the cost of the oil to the mechanic factors in a lot to his choice.

Even if the oils are practically identical, to me it's a no-brainer decision-put in what the manual says to.
First off, there's no such thing as an "oil-related failure". Doesn't happen. If something fails, it's a mechanical failure, and the only two ways oil can even be related to one is if you stray too far away from the recommended oil for your car, or if you don't change it often enough.
Plus, who's going to know? In over 25 years in the car business, I've never seen a manufacturer or even aftermarket warranty company test oil from a failed engine to see if it was the correct weight. I HAVE seen them ask for oil change records to make sure it's been serviced regularly, but that's it.

Secondly, your Honda's identical twin in Japan calls for 5w30. There is no difference in the engines, only the CAFE standards are involved.

Third, there is practically NO difference, as has been stated several times, in 5w20 and 5w30.

In fact, if you look at your owner's manual, I'd just about bet that 5w30 would be one of the options you can use if you're in a hotter climate. I've never seen a manual that only stated "use this weight oil regardless of climate or use of vehicle".

edit: Oh, and finally, while your odds of finding a good mechanic at the dealership are definitely better, if you do have an independent mechanic that has a good reputation, I'd have no problem at all having him swap the engine.....it's not brain surgery.
 

ThePresence

Elite Member
Nov 19, 2001
27,727
16
81
Originally posted by: Zenmervolt
Originally posted by: chucky2
You'll probably even notice a little bit quicker rev'ing of the engine.

You may indeed notice this. It won't actually be there in reality, but it's possible that people will notice it. After all, some people notice improvement from fuel line magnets.

5w20 and 5w30 are essentially interchangeable. It's not possible for 5w30 to cause problems in engines that specify 5w20. 5w20 can also be more difficult to find at a local auto parts store (though this has improved significantly so it shouldn't be an issue any longer), so if you can't find 5w20, 5w30 will be perfectly fine.

As always, I do not recommend mixing two viscosities.

ZV

If they're interchangeable why would it be a problem to mix the two?
 

Pacfanweb

Lifer
Jan 2, 2000
13,154
58
91
Originally posted by: ThePresence
Originally posted by: Zenmervolt
Originally posted by: chucky2
You'll probably even notice a little bit quicker rev'ing of the engine.

You may indeed notice this. It won't actually be there in reality, but it's possible that people will notice it. After all, some people notice improvement from fuel line magnets.

5w20 and 5w30 are essentially interchangeable. It's not possible for 5w30 to cause problems in engines that specify 5w20. 5w20 can also be more difficult to find at a local auto parts store (though this has improved significantly so it shouldn't be an issue any longer), so if you can't find 5w20, 5w30 will be perfectly fine.

As always, I do not recommend mixing two viscosities.

ZV

If they're interchangeable why would it be a problem to mix the two?
It's not a problem, just a "better safe than sorry" thing.

edit: Obviously, if you are changing the oil, you went out and bought all the same weight. If you need a top off, and all you have available is say, 5w20 and your car has 5w30 in it, not a problem.