5W-40 All year round?

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I may just keep my car on 5W-40 all year round if analysis yields good results.

It should offer the same protection as 5W-30 since they are both 5W oils right?? Just want to be sure I'm not missing something.

I did search the forums but saw some mixed results on what to use during the winter.
 
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Originally Posted By: Realtech214
5w40 is fine. If your car calls for 5w30? why not use that?


They manual recommends both grades, my logic is if i use a 40 weight it will shear down to a 30 weight. If I use a 30 I'll get a 20 weight, I'd rather have as much protection as possible.
 
Originally Posted By: Swift101
Originally Posted By: Realtech214
5w40 is fine. If your car calls for 5w30? why not use that?


They manual recommends both grades, my logic is if i use a 40 weight it will shear down to a 30 weight. If I use a 30 I'll get a 20 weight, I'd rather have as much protection as possible.


The manufacturer accounts for that in the recommendation. Also, a bit of shearing is not necessarily a bad thing. Don't assume it will actually shear out of grade. Also, thicker is not always better.

My opinion is to use the 5w30 year round unless your driving style necessitates the 5w40.
 
Originally Posted By: Swift101
Originally Posted By: Realtech214
5w40 is fine. If your car calls for 5w30? why not use that?


They manual recommends both grades, my logic is if i use a 40 weight it will shear down to a 30 weight. If I use a 30 I'll get a 20 weight, I'd rather have as much protection as possible.


If you're doing a 4K Mile OCI on PU that is a complete waste, and you will never have to worry about shear in that timeframe
 
I'll most likely get an analysis done on both grades to see how they handle shearing & fuel dilution.

Most UOAs show my car shears oil in just 3K but I know everyone's driving style is different & other factors can determine results.
 
Originally Posted By: aquariuscsm
I'd go with the 40 wt year round.


Exactly how I feel, there are days were I drive the car hard, very hard.
 
Originally Posted By: Swift101
Originally Posted By: aquariuscsm
I'd go with the 40 wt year round.


Exactly how I feel, there are days were I drive the car hard, very hard.


Right on!
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Originally Posted By: Swift101
It should offer the same protection as 5W-30 since they are both 5W oils right??

No, xW part has nothing to do with the viscosity. It only determines the extreme-cold-start ability in the winter. "W" means winter.

5W-30 will be a lot thinner than 5W-40 with a cold engine; therefore, it will offer better protection with a cold engine. Moreover, 5W-40 will put unnecessary strain on your oil pump at all temperatures. Use 5W-40 only if you are mostly driving the car in extreme speeds or in high speeds climbing mountains.

Fully synthetic 5W-30 SN / Resource Conserving / GF-5 is the correct oil for your car and you will also save up to 5% in fuel costs. Your engine will probably last longer, too.
 
Originally Posted By: Gokhan
5W-30 will be a lot thinner than 5W-40 with a cold engine; therefore, it will offer better protection with a cold engine.


Claims such as this should be quantifiable...there's a pile of prematurely worn engines as you enter Europe that you can surely point to...

Oil will be flowing in seconds in either, how can there be a material difference in "cold" protection, at any normal 5W climate...how does the API get it so wrong ?


Originally Posted By: Gokhan
Moreover, 5W-40 will put unnecessary strain on your oil pump at all temperatures.


Similarly scare mongering claptrap...failed oil pumps and driveshafts...where

Originally Posted By: Gokhan
Fully synthetic 5W-30 SN / Resource Conserving / GF-5 is the correct oil for your car and you will also save up to 5% in fuel costs.


OK, demonstrate the basis for your 5%GF-5 doesn't claim that, the test requirements aren't anywhere near that, particularly after 100 hours, where are you getting justification for 5% ?

Originally Posted By: Gokhan
Your engine will probably last longer, too.


Give us an explaination on how this could be...5W either will be flowing within a second or so in either case.
 
If your manual states the "prefered" weight is 5w30 then I would use that. The comments that a 30 will shear to a 20 is not a given by any means if you look at UOAs. Ed
 
Originally Posted By: Shannow
Originally Posted By: Gokhan
Fully synthetic 5W-30 SN / Resource Conserving / GF-5 is the correct oil for your car and you will also save up to 5% in fuel costs.


OK, demonstrate the basis for your 5%

He wrote "up to" 5%. So it could be anything, including zero.
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Hi,
Gokhan - You said this;

"5W-30 will be a lot thinner than 5W-40 with a cold engine; therefore, it will offer better protection with a cold engine. Moreover, 5W-40 will put unnecessary strain on your oil pump at all temperatures. Use 5W-40 only if you are mostly driving the car in extreme speeds or in high speeds climbing mountains."

Can you provide any verifiable substance to these claims and suggestions?
 
Originally Posted By: Quattro Pete
Originally Posted By: Shannow
Originally Posted By: Gokhan
Fully synthetic 5W-30 SN / Resource Conserving / GF-5 is the correct oil for your car and you will also save up to 5% in fuel costs.

OK, demonstrate the basis for your 5%

He wrote "up to" 5%. So it could be anything, including zero.
smile.gif


Including the negative numbers.
laugh.gif
 
Hi Doug,

FWIU, any 5W-40 is thicker than any 5W-30 at really cold temperatures, as measured by MRV or CCV.
Is this not the case?
As for this causing any harm, we used to use 10W-40 in everything and our engines started on the coldest of mornings with no excess wear or oil pump damage ever noted.
I've also used 5W-40 in winter driven cars for which 5W-30 was the original recommended and for which 5W-20 was later recommended.
I never saw any problems of any kind.
 
Given your climate, I would think using 0w40 would be the best. Hyundai might not mention the use of 0w40, but the viscosity at operating temperature is what an oil analysis tests for, so Hyundai can't say you used the wrong oil.

And you can use 0w40 syn all year. I see turbo guys in Florida use M1 0w40, and they never have any problem with it.
 
The only warning I'd have against 5w-40 is cost over the short, factory mandated OCIs in your vehicle. You can get a 5w-30 SN/GF-5 conventional, but you're not going to find a 5w-40 conventional. Up here, Delvac 1 ESP 5w-40 is priced much the same as regularly priced conventionals, so that's a big attraction for me.

I had no problems - real or imagined - using it all winter, either, and we had a terrible winter.
 
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