Is fuel dilution taken into account when they recommend xw-20?

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I have heard quite a few people say to run a higher weighted oil than is printed on the oil cap due to fuel dilution on GDI cars (so 5w30 instead of 5w20). When the manufacturers select the oil to be recommended on the oil cap, do they take into account fuel dilution that will likely occur?
 
Honda sure doesn't
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They say to use 0w20 in a turbo (their 1.5T). Oh, and regular gas, too!
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(87 octane US, 91 RON)

Much less of a problem with 5w30 and premium
 
And, change the oil every 3000 miles ...


Our Honda Pilot gets short tripped in cold winter temperatures, the EXACT scenario giving Honda, and I would assume other manufacturers, grief. The oil turns very dark very quickly, and smells strongly of gas. Plus, a little goo on the oil fill cap. In the summer, none of this happens ...

I do an extra oil change in the winter, and use a 30 grade oil.

Just like the old days !
 
If they do, good luck getting them to admit it... think about it.

I can see the commercial now...

"The new 2020 Accord, featuring less fuel sneaking past the oil rings and contaminating the oil, than our 2019 model Accord"...‚


Ok, all joking aside..I don't think you would ever uncover official internal corporate engineer's notes saying "minimum Xw30 needed for fuel dilution"... that could explode into a yuuuuge class action suit, potentially.
 
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I think oxidation may eventually cancel out and even take over dilution ...
That's why Seq IIIH test allows up to %150 viscosity increase ... I'm guessing, maybe experts can correct me. It may take much longer than most people wait to get there though!

The maximum allowable viscosity increase is:
%150 IIIH SN/SN Plus/GF-5
%100 GF-6
 
Hyundai/Kia allow the use of 5W20 , 5W30 and 10W30 based on ambient temps the owner expects to use the vehicle during the OCI ... My 2.4L GDI engine oil smells strongly of gas by the 3K mile mark ,so I go up a grade over a 3,750 mile OCI using a 5W30 D1/G2 rated synthetic just to have some head room in case of fuel dilution .
 
Originally Posted by ChrisD46
Hyundai/Kia allow the use of 5W20 , 5W30 and 10W30 based on ambient temps the owner expects to use the vehicle during the OCI ... My 2.4L GDI engine oil smells strongly of gas by the 3K mile mark ,so I go up a grade over a 3,750 mile OCI using a 5W30 D1/G2 rated synthetic just to have some head room in case of fuel dilution .

ðŸ‘... smart move. I am thankful that Hyundai/Kia provides owners with flexibility in choice of grade.
 
I often think of this myself...am I just part of a CAFE regulation scheme by the manufacturer to get my vehicle any advantage for a slight uptick in fuel economy, while not doing what is best for my engine because the manufacturer won't be responsible when it's out of warranty.

My truck calls for 0W20, but I wonder if it would be better to run 0W30 or 5W30? I do smell fuel in that oil at times when I empty my catch can....others times not so much. And others that own the GM direct injected 5.3 have reported fuel dilution in their oil samples (and certainly oil consumption).
 
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Originally Posted by ChrisD46
Hyundai/Kia allow the use of 5W20 , 5W30 and 10W30 based on ambient temps the owner expects to use the vehicle during the OCI ... My 2.4L GDI engine oil smells strongly of gas by the 3K mile mark ,so I go up a grade over a 3,750 mile OCI using a 5W30 D1/G2 rated synthetic just to have some head room in case of fuel dilution .

That is precisely what I instructed my son to do when he bought a new KIA last year. I told him to run Mobil 1 EP 5W30, and stick to a 4K OCI.
 
How about the new DI cars specifying 0W-16. They better not be big fuel dilluters.
 
Originally Posted by Railrust
I often think of this myself...am I just part of a CAFE regulation scheme by the manufacturer to get my vehicle any advantage for a slight uptick in fuel economy, while not doing what is best for my engine because the manufacturer won't be responsible when it's out of warranty.


Yep, pretty much. But most street cars are not driven very hard, which helps them last with thinner oil.
 
My 2010 5.3L was 6 quarts of 5w30
My 2018 5.3L is 8 quarts of 0w20
Several other mechanical changes
 
Originally Posted by ZeeOSix
How about the new DI cars specifying 0W-16. They better not be big fuel dilluters.

You're right. I say give it a few years we'll know for sure just how well they hold up. Any comments and observations now are too soon imo to come to any conclusions.
 
*I plan to do a UOA after one of my upcoming 3,750 mile oil runs with an oil I think I like . Going up to a M1 5W30 EP or Castrol EP might get me up to 6K mile OCI's which is what my other vehicles get .
Originally Posted by demarpaint
Originally Posted by ChrisD46
Hyundai/Kia allow the use of 5W20 , 5W30 and 10W30 based on ambient temps the owner expects to use the vehicle during the OCI ... My 2.4L GDI engine oil smells strongly of gas by the 3K mile mark ,so I go up a grade over a 3,750 mile OCI using a 5W30 D1/G2 rated synthetic just to have some head room in case of fuel dilution .

That is precisely what I instructed my son to do when he bought a new KIA last year. I told him to run Mobil 1 EP 5W30, and stick to a 4K OCI.
 
Originally Posted by ChrisD46
*I plan to do a UOA after one of my upcoming 3,750 mile oil runs with an oil I think I like . Going up to a M1 5W30 EP or Castrol EP might get me up to 6K mile OCI's which is what my other vehicles get .
Originally Posted by demarpaint
Originally Posted by ChrisD46
Hyundai/Kia allow the use of 5W20 , 5W30 and 10W30 based on ambient temps the owner expects to use the vehicle during the OCI ... My 2.4L GDI engine oil smells strongly of gas by the 3K mile mark ,so I go up a grade over a 3,750 mile OCI using a 5W30 D1/G2 rated synthetic just to have some head room in case of fuel dilution .

That is precisely what I instructed my son to do when he bought a new KIA last year. I told him to run Mobil 1 EP 5W30, and stick to a 4K OCI.


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Just listen for rapping or knocking and adjust accordingly.

Been doing this for years with the Big Bore Subaru EJ engines,

Sub 1 qt same brand/tier 5w30 or 10w30

If that's not enough Sub 1.5 qt.

Why not go whole hog 5W30? It may BOG.

Plus you will have a 20 grade receipt for that 5Q jug. for your warranty.
 
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Originally Posted by BMWTurboDzl
Evidence suggests that some fuel dilution is not an issue so I imagine yes they took that into consideration.


Couldn't agree more with this. I think fuel dilution is so blown out of proportion around here. We've seen many uoa's of the "terrible" 1.5T honda motors and wear metals aren't bad at all, many are totally acceptable.
 
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