It seems most people on this forum recommend or use 5w20 or 5w30 for passenger vehicles. 10w40 used to be very common 20 years ago (I remember it was cheaper than 10w30), so why don't people use it much anymore? Is it just because of fuel economy, or does it not protect as well as 5w30?
10w40 falling out of favor?
- Thread starter tonycarguy
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I use 5w30 because that's what both of our rigs call for, both in the manual and on the fill cap. I could prolly run 10W-40 in the summer around here, but what would be the point?
I think tighter engine tolerances and CAFE regs have driven down the recommended oil weights for most cars/trucks over the last ten years. Also, the proliferation/acceptance of synthetics has made it possible to run 0W oils, and that appeals to many in colder climates.
I think tighter engine tolerances and CAFE regs have driven down the recommended oil weights for most cars/trucks over the last ten years. Also, the proliferation/acceptance of synthetics has made it possible to run 0W oils, and that appeals to many in colder climates.
JHZR2
Staff member
10w-40 did fall out of favor as automakers went to 10w30 and 5w30 ad their warranty oil. 10w-40 had a bad reputation with the large amounts of VIIs breaking down and sludging up. Good protection of a heavier oil was negated by the oil breaking down.
Chemistry has taken us far in the realm of advanced conventional and synthetic basestocks, as well as additives. These days a good add pack can be as important to the oil's performance as viscosity at the bearings. Most cheap basestocks are still more consistent and better performance than what was had.
The ability to produce consistent, shear-stable, good performing 30wt oils makes a 10w-40 obsolete in most uses. And, the uses where it may be justified, we have both excellent conventional 15w40 HDEOs (good down to about 0 F) and excellent synthetic 5w-40 HDEOs which meet all needs.
Chemistry has taken us far in the realm of advanced conventional and synthetic basestocks, as well as additives. These days a good add pack can be as important to the oil's performance as viscosity at the bearings. Most cheap basestocks are still more consistent and better performance than what was had.
The ability to produce consistent, shear-stable, good performing 30wt oils makes a 10w-40 obsolete in most uses. And, the uses where it may be justified, we have both excellent conventional 15w40 HDEOs (good down to about 0 F) and excellent synthetic 5w-40 HDEOs which meet all needs.
I must admit that even I, a big fan of 10w40 at one time, have thrown in the towel. I have 17 qts of 10w40 left in my stash that I would sell off, but will use to thicken 30 wt oil a bit. IMO, the best grade is 10w30, but it should be closer to 11.5 cST, not the typical 10.5 cSt. 10w30 is about the perfect grade as it does not have too much VII spread yet can handle pretty cold conditions. If extreme cold, I'll go synthetic 10w30 and if necessary syn 5w30. I would even run a 20 wt if only doing short trips in winter as it will never get thinner than a 30 weight in that operating scheme.
Of course the ideal oil is a synthetic 5w30 or 0w30 that has no VII and so essentially is a straight 30 weight. Redline comes to mind.
Of course the ideal oil is a synthetic 5w30 or 0w30 that has no VII and so essentially is a straight 30 weight. Redline comes to mind.
I use 10w-40 in Euro cars. PZYB or Havoline DS. Works fine for me.
I still use 10W40 in some of my vehicles.
I use 10W40 in the summer in my older vehicles that use a bit of oil. I don't know if it slows things down or not. It does give me something to do come springtime, LOL.
For the life of me, I don't understand why people are so critical of modern 10W-40's. If you look at the spec sheets for most oils, the 10W-40 grade has often the exact same VI as the 5w30 grade. This would indicate that both oils use a 'similar' amount of VII's, which is what everyone 'fears'.
Yet a ton of people on this board use 5w30 oils without any worry of sludging up there engines...with the quality of todays base oils, and additives, a 10W-40 is no better or worse than a 5w30.
Also, most modern 10W-40's have CCS values close to that of their 10w30 counterpart, and a lot of people have no problem running 10w30 in the winter, so 10W-40 would be no worse.
I think 10W-40 is a great alternative to 5w30/10W-30 where you have an older engine that makes some noise, or consumes some oil. Todays 10W-40's are NOTHING like the ones that were produced in the 1970's - but I even wonder if 1970's 10W-40 were THAT bad, or was it just a lack of detergency in oils of that time that led to excessive deposits and resulting sludge?
Yet a ton of people on this board use 5w30 oils without any worry of sludging up there engines...with the quality of todays base oils, and additives, a 10W-40 is no better or worse than a 5w30.
Also, most modern 10W-40's have CCS values close to that of their 10w30 counterpart, and a lot of people have no problem running 10w30 in the winter, so 10W-40 would be no worse.
I think 10W-40 is a great alternative to 5w30/10W-30 where you have an older engine that makes some noise, or consumes some oil. Todays 10W-40's are NOTHING like the ones that were produced in the 1970's - but I even wonder if 1970's 10W-40 were THAT bad, or was it just a lack of detergency in oils of that time that led to excessive deposits and resulting sludge?
Originally Posted By: addyguy
but I even wonder if 1970's 10W-40 were THAT bad, or was it just a lack of detergency in oils of that time that led to excessive deposits and resulting sludge?
They were bad enough that SAE J300 called them light duty oils and they only had to meet the same HTHS requirements as xW-30 oils. The viscosity of a 40 with the high temperature protection of a 30.
They are generality better now.
but I even wonder if 1970's 10W-40 were THAT bad, or was it just a lack of detergency in oils of that time that led to excessive deposits and resulting sludge?
They were bad enough that SAE J300 called them light duty oils and they only had to meet the same HTHS requirements as xW-30 oils. The viscosity of a 40 with the high temperature protection of a 30.
They are generality better now.
It was also the old emissions/PCV.
Originally Posted By: TallPaul
I must admit that even I, a big fan of 10w40 at one time, have thrown in the towel. I have 17 qts of 10w40 left in my stash that I would sell off, but will use to thicken 30 wt oil a bit. IMO, the best grade is 10w30, but it should be closer to 11.5 cST, not the typical 10.5 cSt. 10w30 is about the perfect grade as it does not have too much VII spread yet can handle pretty cold conditions. If extreme cold, I'll go synthetic 10w30 and if necessary syn 5w30. I would even run a 20 wt if only doing short trips in winter as it will never get thinner than a 30 weight in that operating scheme.
Of course the ideal oil is a synthetic 5w30 or 0w30 that has no VII and so essentially is a straight 30 weight. Redline comes to mind.
You sir made my day...I live where it gets down to 0* (rarely) and as hot as 110*... on avg, 25*-100* I'd say depending on time of year.
Anyway, I have ALWAYS used 10w30 in every car I have owned since 1992...some dino, some syn, but always 10w30
With all these exotic oils & weights, I am confused but you seem to be well respected on here and have reassured me that I am doing just fine using the 10w30 in my diverse climate.
Now in some family member's cars, I have used 5w30 because they want what it calls for. But heck even in cold weather, I use a blend or full syn sometimes but still 10w30 so you have helped me out.
I would use 10w40 in my HM Jeep if it used too much oil or leaked too bad, but 10w30 seems to do it well and it doesn't puff any blue smoke after 178k so far.
I must admit that even I, a big fan of 10w40 at one time, have thrown in the towel. I have 17 qts of 10w40 left in my stash that I would sell off, but will use to thicken 30 wt oil a bit. IMO, the best grade is 10w30, but it should be closer to 11.5 cST, not the typical 10.5 cSt. 10w30 is about the perfect grade as it does not have too much VII spread yet can handle pretty cold conditions. If extreme cold, I'll go synthetic 10w30 and if necessary syn 5w30. I would even run a 20 wt if only doing short trips in winter as it will never get thinner than a 30 weight in that operating scheme.
Of course the ideal oil is a synthetic 5w30 or 0w30 that has no VII and so essentially is a straight 30 weight. Redline comes to mind.
You sir made my day...I live where it gets down to 0* (rarely) and as hot as 110*... on avg, 25*-100* I'd say depending on time of year.
Anyway, I have ALWAYS used 10w30 in every car I have owned since 1992...some dino, some syn, but always 10w30
With all these exotic oils & weights, I am confused but you seem to be well respected on here and have reassured me that I am doing just fine using the 10w30 in my diverse climate.
Now in some family member's cars, I have used 5w30 because they want what it calls for. But heck even in cold weather, I use a blend or full syn sometimes but still 10w30 so you have helped me out.
I would use 10w40 in my HM Jeep if it used too much oil or leaked too bad, but 10w30 seems to do it well and it doesn't puff any blue smoke after 178k so far.
didn't Ford really get the anti 10w-40 movment going back when the 4.6 V8 came out? they claimed it was too thick, esp in the north, they claimed that it broke down causing sludge, plus what i was told at the time old dino 10w-40 just broke down too fast, 3000 miles was often to long for it.
I can see the problem: old farts were hooked on dino 10w-40, didn't change it often enough, and had in the motor when it was winter with days of cold starting below O F
I can see the problem: old farts were hooked on dino 10w-40, didn't change it often enough, and had in the motor when it was winter with days of cold starting below O F
Thanks, and if you do want a 40 weight for summer, 15w40 is a better way to go. The API engine oil classification (2004, but probably has not changed) says 10w40 must meet minimum HTHS of 2.9, whereas a 15w40 must have a minimum HTHS of 3.7! That and the spread is tighter on the 15w40.
Actually I am seriosly considering running straight 30 in the F150 ('95 4.9L) and the Aerostar ('92 3.0L) this summer. Happen to have a case of Valvoline Premium Conventional straight 30 I picked up on sale and am itching to try it out.
Actually I am seriosly considering running straight 30 in the F150 ('95 4.9L) and the Aerostar ('92 3.0L) this summer. Happen to have a case of Valvoline Premium Conventional straight 30 I picked up on sale and am itching to try it out.
MolaKule
Staff member
Quote:
If you look at the spec sheets for most oils, the 10W-40 grade has often the exact same VI as the 5w30 grade. This would indicate that both oils use a 'similar' amount of VII's, which is what everyone 'fears'.
Not really. The VI is determined by quality of base oils primarily, and additives secondarily.
If you look at the spec sheets for most oils, the 10W-40 grade has often the exact same VI as the 5w30 grade. This would indicate that both oils use a 'similar' amount of VII's, which is what everyone 'fears'.
Not really. The VI is determined by quality of base oils primarily, and additives secondarily.
Originally Posted By: javacontour
I use 10W40 in the summer in my older vehicles that use a bit of oil. I don't know if it slows things down or not. It does give me something to do come springtime, LOL.
I also use 10w40 for all the hi-mileage engines in the family fleet. Have my last jug of Superflo 10w40 saved for the Bonneville this summer.
I use 10W40 in the summer in my older vehicles that use a bit of oil. I don't know if it slows things down or not. It does give me something to do come springtime, LOL.
I also use 10w40 for all the hi-mileage engines in the family fleet. Have my last jug of Superflo 10w40 saved for the Bonneville this summer.
Originally Posted By: MillerMan
didn't Ford really get the anti 10w-40 movment going back when the 4.6 V8 came out? they claimed it was too thick, esp in the north, they claimed that it broke down causing sludge, plus what i was told at the time old dino 10w-40 just broke down too fast, 3000 miles was often to long for it.
I can see the problem: old farts were hooked on dino 10w-40, didn't change it often enough, and had in the motor when it was winter with days of cold starting below O F
Chrysler, as early as the late 1980s, was already banging the anti-10W-40 drum. The recommended 5w30 for colder weather, and 10w30 for warmer climates. But stated one could use 15w40 or SAE30 in very high temperature applications.
They specifically said not to use 10W-40 though.
Personally, I think 10W-40 is fine but see no reason to use it over 10w30 unless a car is using oil...
didn't Ford really get the anti 10w-40 movment going back when the 4.6 V8 came out? they claimed it was too thick, esp in the north, they claimed that it broke down causing sludge, plus what i was told at the time old dino 10w-40 just broke down too fast, 3000 miles was often to long for it.
I can see the problem: old farts were hooked on dino 10w-40, didn't change it often enough, and had in the motor when it was winter with days of cold starting below O F
Chrysler, as early as the late 1980s, was already banging the anti-10W-40 drum. The recommended 5w30 for colder weather, and 10w30 for warmer climates. But stated one could use 15w40 or SAE30 in very high temperature applications.
They specifically said not to use 10W-40 though.
Personally, I think 10W-40 is fine but see no reason to use it over 10w30 unless a car is using oil...
Here is a quote from one of my posts on this subject from 2006:
"5w30 oils began seriously entering the market in the 1980s when the car manufacturers, needing to comply with the government CAFE (Corporate Average Fuel Economy) requirements or pay heavy fines, had to squeeze every drop of fuel savings from every car component possible. In addition to lighter vehicles with more plastic, they targeted thinner oils as a means of saving another couple percent MPG.
One of the manufacturers (I believe Honda) used a Mobil 1 5W-20 synthetic oil in their CAFE qualification test and was disqualified by the EPA on the grounds that this oil was not sufficiently available or reasonably priced to be considered in general use. That set the car manufacturers off on a crusade to get thinner 5W-X oils properly defined, reasonably priced, and readily available on retail shelves. But there was a technical and a marketing problem.
The technical problem was that the light base oils needed to make the 5W-X oils were in tight supply. They quickly and cleverly fixed that by changing the specifications for 5W to allow slightly heavier base oils to be used.
The marketing problem was bigger. Consumers were thoroughly sold for many years that 10W-40 was the ultimate universal grade of oil for all cars, and retailers stocked what consumers bought. So when the oil companies introduced the new 5w30 oils, they were not well received and not given the retail shelf space needed to be considered "readily available". Even though the new car manuals recommended 5w30s, they still had to allow 10W-40s, and the manual recommendations just did not have the reach and power to dislodge the entrenched 10W-40 concept from consumer’s minds. The car manufacturers needed to get more creative.
Seizing on some studies that showed that VI improvers contributed to ring sticking in some engines, and adding to the mix the fact that 10W-40s had a high level of VI improver and GM was having ring sticking problems, GM took the bold move of outright banning 10W-40 oils. Other manufacturers followed and the word got spread around enough to reduce the sales of 10W-40 and increase the sales of 5w30. This change in demand patterns caused more retailers to carry 5w30 oils, and the EPA became satisfied enough that the new grade was now readily available and reasonably priced to allow its use in CAFE qualification tests. Through these bold and clever manipulations, the auto industry was able to avoid government fines and a new grade of oil was born.
Other problems existed, especially wear, but cooperative efforts with oil companies and engine design changes were eventually able to overcome this. It took another decade for 5w30 sales to overtake 10W-40, but the consumer finally began accepting thinner oils."
Tom NJ
"5w30 oils began seriously entering the market in the 1980s when the car manufacturers, needing to comply with the government CAFE (Corporate Average Fuel Economy) requirements or pay heavy fines, had to squeeze every drop of fuel savings from every car component possible. In addition to lighter vehicles with more plastic, they targeted thinner oils as a means of saving another couple percent MPG.
One of the manufacturers (I believe Honda) used a Mobil 1 5W-20 synthetic oil in their CAFE qualification test and was disqualified by the EPA on the grounds that this oil was not sufficiently available or reasonably priced to be considered in general use. That set the car manufacturers off on a crusade to get thinner 5W-X oils properly defined, reasonably priced, and readily available on retail shelves. But there was a technical and a marketing problem.
The technical problem was that the light base oils needed to make the 5W-X oils were in tight supply. They quickly and cleverly fixed that by changing the specifications for 5W to allow slightly heavier base oils to be used.
The marketing problem was bigger. Consumers were thoroughly sold for many years that 10W-40 was the ultimate universal grade of oil for all cars, and retailers stocked what consumers bought. So when the oil companies introduced the new 5w30 oils, they were not well received and not given the retail shelf space needed to be considered "readily available". Even though the new car manuals recommended 5w30s, they still had to allow 10W-40s, and the manual recommendations just did not have the reach and power to dislodge the entrenched 10W-40 concept from consumer’s minds. The car manufacturers needed to get more creative.
Seizing on some studies that showed that VI improvers contributed to ring sticking in some engines, and adding to the mix the fact that 10W-40s had a high level of VI improver and GM was having ring sticking problems, GM took the bold move of outright banning 10W-40 oils. Other manufacturers followed and the word got spread around enough to reduce the sales of 10W-40 and increase the sales of 5w30. This change in demand patterns caused more retailers to carry 5w30 oils, and the EPA became satisfied enough that the new grade was now readily available and reasonably priced to allow its use in CAFE qualification tests. Through these bold and clever manipulations, the auto industry was able to avoid government fines and a new grade of oil was born.
Other problems existed, especially wear, but cooperative efforts with oil companies and engine design changes were eventually able to overcome this. It took another decade for 5w30 sales to overtake 10W-40, but the consumer finally began accepting thinner oils."
Tom NJ
Originally Posted By: Tom NJ
Here is a quote from one of my posts on this subject from 2006:
"5w30 oils began seriously entering the market in the 1980s when the car manufacturers, needing to comply with the government CAFE (Corporate Average Fuel Economy) requirements or pay heavy fines, had to squeeze every drop of fuel savings from every car component possible. In addition to lighter vehicles with more plastic, they targeted thinner oils as a means of saving another couple percent MPG.
One of the manufacturers (I believe Honda) used a Mobil 1 5W-20 synthetic oil in their CAFE qualification test and was disqualified by the EPA on the grounds that this oil was not sufficiently available or reasonably priced to be considered in general use. That set the car manufacturers off on a crusade to get thinner 5W-X oils properly defined, reasonably priced, and readily available on retail shelves. But there was a technical and a marketing problem.
The technical problem was that the light base oils needed to make the 5W-X oils were in tight supply. They quickly and cleverly fixed that by changing the specifications for 5W to allow slightly heavier base oils to be used.
The marketing problem was bigger. Consumers were thoroughly sold for many years that 10W-40 was the ultimate universal grade of oil for all cars, and retailers stocked what consumers bought. So when the oil companies introduced the new 5w30 oils, they were not well received and not given the retail shelf space needed to be considered "readily available". Even though the new car manuals recommended 5w30s, they still had to allow 10W-40s, and the manual recommendations just did not have the reach and power to dislodge the entrenched 10W-40 concept from consumer’s minds. The car manufacturers needed to get more creative.
Seizing on some studies that showed that VI improvers contributed to ring sticking in some engines, and adding to the mix the fact that 10W-40s had a high level of VI improver and GM was having ring sticking problems, GM took the bold move of outright banning 10W-40 oils. Other manufacturers followed and the word got spread around enough to reduce the sales of 10W-40 and increase the sales of 5w30. This change in demand patterns caused more retailers to carry 5w30 oils, and the EPA became satisfied enough that the new grade was now readily available and reasonably priced to allow its use in CAFE qualification tests. Through these bold and clever manipulations, the auto industry was able to avoid government fines and a new grade of oil was born.
Other problems existed, especially wear, but cooperative efforts with oil companies and engine design changes were eventually able to overcome this. It took another decade for 5w30 sales to overtake 10W-40, but the consumer finally began accepting thinner oils."
Tom NJ
Very well put...kudos...
But again, I think a 10w30 is the best of both worlds between 5w30 & 10w40...why not ban them both and just use 10w30 and make syn 10w30 FF in coldeer areas? LOL
Here is a quote from one of my posts on this subject from 2006:
"5w30 oils began seriously entering the market in the 1980s when the car manufacturers, needing to comply with the government CAFE (Corporate Average Fuel Economy) requirements or pay heavy fines, had to squeeze every drop of fuel savings from every car component possible. In addition to lighter vehicles with more plastic, they targeted thinner oils as a means of saving another couple percent MPG.
One of the manufacturers (I believe Honda) used a Mobil 1 5W-20 synthetic oil in their CAFE qualification test and was disqualified by the EPA on the grounds that this oil was not sufficiently available or reasonably priced to be considered in general use. That set the car manufacturers off on a crusade to get thinner 5W-X oils properly defined, reasonably priced, and readily available on retail shelves. But there was a technical and a marketing problem.
The technical problem was that the light base oils needed to make the 5W-X oils were in tight supply. They quickly and cleverly fixed that by changing the specifications for 5W to allow slightly heavier base oils to be used.
The marketing problem was bigger. Consumers were thoroughly sold for many years that 10W-40 was the ultimate universal grade of oil for all cars, and retailers stocked what consumers bought. So when the oil companies introduced the new 5w30 oils, they were not well received and not given the retail shelf space needed to be considered "readily available". Even though the new car manuals recommended 5w30s, they still had to allow 10W-40s, and the manual recommendations just did not have the reach and power to dislodge the entrenched 10W-40 concept from consumer’s minds. The car manufacturers needed to get more creative.
Seizing on some studies that showed that VI improvers contributed to ring sticking in some engines, and adding to the mix the fact that 10W-40s had a high level of VI improver and GM was having ring sticking problems, GM took the bold move of outright banning 10W-40 oils. Other manufacturers followed and the word got spread around enough to reduce the sales of 10W-40 and increase the sales of 5w30. This change in demand patterns caused more retailers to carry 5w30 oils, and the EPA became satisfied enough that the new grade was now readily available and reasonably priced to allow its use in CAFE qualification tests. Through these bold and clever manipulations, the auto industry was able to avoid government fines and a new grade of oil was born.
Other problems existed, especially wear, but cooperative efforts with oil companies and engine design changes were eventually able to overcome this. It took another decade for 5w30 sales to overtake 10W-40, but the consumer finally began accepting thinner oils."
Tom NJ
Very well put...kudos...
But again, I think a 10w30 is the best of both worlds between 5w30 & 10w40...why not ban them both and just use 10w30 and make syn 10w30 FF in coldeer areas? LOL
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