how come so many people change to a thicker oil or think there oil is too thin?

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1,237
How do we know the vehicles spec’d for 0W/5W-20 haven’t actually been using higher grade oil? We don’t, you can’t make that assumption. It seems like most people I know who have/had any vehicle with the Ford 4.6 mod motor have used 5w-30. Same thing with a LOT of Honda 4cylinder engines. Most switch to a 5w-30 or higher because of oil burning. Heck, it’s even become a trend now for a lot of Toyota owners to bump up in viscosity due to the oil burning that plagues several of their 4 cylinder engines. I’m betting there is a SMALL percentage of engines making it all the way to 300K miles on 0W/5W-20. I strongly suspect that the majority of 300k mile engines have been upgraded to a thicker oil to control oil consumption, and because subsequent owners are less likely to follow owners manual recommendations. Not saying 0W/5W-20 oils aren’t up for the challenge, I’m just saying there are a lot of reasons why people have moved up a grade.

Also, you stated you occasionally bump up to 5W-30 in your Rogue because that’s the spec in other countries. I guarantee you a lot of other people do the same in their vehicles.

It’s likely very minimal as we’ve seen tons of 300+k mile engines that used 0w20 their whole lives.

My personal experience in bumping grade is I run 5w30 on the Rogue instead of 0w20 occasionally because the exact same engine (QR25DE) in it in other countries that mirror my climate (Saudi Arabia, UAE) and applications (Nissan Frontier 4 cylinder) call for 5w30 so I know it’s safe to use.
 
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647
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Owners manuals in the 1960’s-1970’s stated higher oil consumption on 5W-30 with prolong highway use. That was half a century ago, and 5W-30 has been OEM spec for decades now for many vehicles.
Cars these days dont run hard on the highway either thanks to overdrive transmissions.
 
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147
How do we know the vehicles spec’d for 0W/5W-20 haven’t actually been using higher grade oil? We don’t, you can’t make that assumption. It seems like most people I know who have/had any vehicle with the Ford 4.6 mod motor have used 5w-30. Same thing with a LOT of Honda 4cylinder engines. Most switch to a 5w-30 or higher because of oil burning. Heck, it’s even become a trend now for a lot of Toyota owners to bump up in viscosity due to the oil burning that plagues several of their 4 cylinder engines. I’m betting there is a SMALL percentage of engines making it all the way to 300K miles on 0W/5W-20. I strongly suspect that the majority of 300k mile engines have been upgraded to a thicker oil to control oil consumption, and because subsequent owners are less likely to follow owners manual recommendations. Not saying 0W/5W-20 oils aren’t up for the challenge, I’m just saying there are a lot of reasons why people have moved up a grade.

Also, you stated you occasionally bump up to 5W-30 in your Rogue because that’s the spec in other countries. I guarantee you a lot of other people do the same in their vehicles.
I do partly agree on this, however vehicles like taxis and corporate lease cars etc.. are almost always dealer maintained and sometimes run 300k miles in only a couple of years. I dont think dealers will divert from the oem specced oil.

I have build several performance engines and know that it all has to do with the machining quality and tolerances that where used.
In theory there is almost no metal to metal contact in an engine except for piston rings etc..

If parts where to hit metal on metal, for example the rod bearings. They will fail in a matter of seconds/minutes.
This is the case with for example 0w20 or 10w40. No contact = no wear metal contact=engine failure will be verry soon and absolutly happen.

There is no such thing as only a little metal to metal contact with thinner oil.

Engine failure is very rare in modern cars, if there are failures its usally common due to design or material flaw etc... thicker oil will almost never help to prevent it.

Thats why factory spec is absolutly safe to use. Only watch out for fuel dilliution with short distance driving etc..
Thicker oil was in the time when tolerances and machining quality was poor.
 
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1,451
Sorry to bring this up if its already been spoken about. So what I have read is that a 5w20 is usually just oem fill for most vehicles because apparently they can save about 1% of fuel economy compared to a 5w30 oil and that big difference across there entire fleet results in meeting the requirements of CAFE/EPA or whatever. However tons of people seem to think that a 5w20 is too thin and that a 5w30 would provide better protection and that most engines need thicker oil. I am a man of following owners manuals and what engineers and manufacturers say, and if a vehicle says 5w20 then I use that and if a diff vehicle says 5w30 then i use that. I assume the vehicles that have 5w20 have tighter tolerances compared to a vehicle that is prescribed to take 5W30.


So what I wanted to ask is that is there actual proof or evidence or is it just hearsay that 5w20 is "too thin" and that a 5w30 would provide more protection and that any vehicle that has 5w20 would prefer a "thicker oil"?

In my uneducated opinion which could be totally wrong is that people tend to overthink stuff too much and that we shouldn't be changing our oil weights from what the manufacturer says unless for example we live in a climate very very cold or very very hot because i assume the manufactuer assumes normal temperature conditions. I feel like a 5w20 probably provides enough protection and I don't think a manufacturer or engineering team would prescribe our vehicles with a thinner oil if they would not be protected by that certain oil weight etc. Unless there is proven evidence from maybe labs or UOA's or something else to prove it, I don't think my opinion would change. For example if a UOA shows that the vehicle has more wear metals with a 5w20 compared to a 5w30 then that makes sense to me and I would believe that a 5w30 protects better or whatever other test to provide evidence


even with older vehicles for examples, like do tolerances change that much in an engine in which they need a thicker oil for more protection? i dont seem to be convinced considering i know tons of vehicles that are at like 250,000 miles on the original engine using the original oil weight, so I still don't understand why so many people see the need to get a thicker oil after x amount of miles on the engine



thanks!
They haven't got a clue.. And have too much time on their hands to read charts.. If they had a clue they should be wearing a white coat in a lab. "5w30" is 5w30 thick or thin on paper.. Reality it's still 5w30
 
Messages
372
Location
Scottsdale, AZ
How do we know the vehicles spec’d for 0W/5W-20 haven’t actually been using higher grade oil? We don’t, you can’t make that assumption. It seems like most people I know who have/had any vehicle with the Ford 4.6 mod motor have used 5w-30. Same thing with a LOT of Honda 4cylinder engines. Most switch to a 5w-30 or higher because of oil burning. Heck, it’s even become a trend now for a lot of Toyota owners to bump up in viscosity due to the oil burning that plagues several of their 4 cylinder engines. I’m betting there is a SMALL percentage of engines making it all the way to 300K miles on 0W/5W-20. I strongly suspect that the majority of 300k mile engines have been upgraded to a thicker oil to control oil consumption, and because subsequent owners are less likely to follow owners manual recommendations. Not saying 0W/5W-20 oils aren’t up for the challenge, I’m just saying there are a lot of reasons why people have moved up a grade.

Also, you stated you occasionally bump up to 5W-30 in your Rogue because that’s the spec in other countries. I guarantee you a lot of other people do the same in their vehicles.
Overall I’d say the vast majority of people go to a shop to have their oil changed.

People who change their oil these days are enthusiasts, cheap, or have just been doing it from when it was the norm and the quick lube places where a luxury. Almost every chain auto repair shop/quick lube has an electronic oil distribution system that at the bare minimum tells the tech what viscosity to use (from the Mfg data) and probably automatically dispenses that specific oil in the exact service fill quantity. I’d guess nearly every company car or fleet vehicle is serviced this way (I always took my company car to the dealer since I wasn’t paying) so I do think that the vast majority of cars out there are run in the oil spec the vast majority of their lives.

The foreign manual thing is probably more of an outlier and justification for enthusiasts. I use it because I live in the desert and it’s a bazillion degrees all the time and the UAE manuals are all in English, they do call for 20w50 in our cars pretty nuts when the US it calls for 0w20 guessing skiing isn’t a big business in Dubai.
 
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Overall I’d say the vast majority of people go to a shop to have their oil changed.

People who change their oil these days are enthusiasts, cheap, or have just been doing it from when it was the norm and the quick lube places where a luxury. Almost every chain auto repair shop/quick lube has an electronic oil distribution system that at the bare minimum tells the tech what viscosity to use (from the Mfg data) and probably automatically dispenses that specific oil in the exact service fill quantity. I’d guess nearly every company car or fleet vehicle is serviced this way (I always took my company car to the dealer since I wasn’t paying) so I do think that the vast majority of cars out there are run in the oil spec the vast majority of their lives.

The foreign manual thing is probably more of an outlier and justification for enthusiasts. I use it because I live in the desert and it’s a bazillion degrees all the time and the UAE manuals are all in English, they do call for 20w50 in our cars pretty nuts when the US it calls for 0w20 guessing skiing isn’t a big business in Dubai.


Actually it is.

 
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1,237
I guess that’s another thing. Most rental car companies use 5W-30 across their fleets. There have been a few members here that work in the oil change business and have stated exactly that. I’m also going to venture and say a lot of dealerships use 5W-30 unless you pay extra for synthetic. Most dealerships I’ve been to up sell 0W-20 as a “synthetic oil package”. The Hyundai dealer I use for warranty/recall work uses, you guessed it, 5w-30 for their oil changes. I’ve seen plenty of dealers of different brands use 5W-30 as their regular oil change. With 5W-20 requiring the customer to purchase a “synthetic blend package”, and 0W-20 requiring a “synthetic package”.
 
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