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

Messages
23,675
Location
Dallas,Tx USA
Thicker oil generally provides better protection. The question is whether or not you need it. Most people simply do not. It would be like if you wore football pads to go grocery shopping. I mean yeah sure I guess you are safer...?
I agree. That's why almost ever manual (even the current Corolla) says to use a higher viscosity oil for better protection during extreme use (towing, racing, extended high speed driving, etc), but says to switch back to the lighter one (0W16) for *FUEL ECONOMY*.
 
Messages
920
Location
Saint Nazianz, WI
Here is what I can share, I am using up the last of my SN+/GF5 rated Valvoline Synthetic Maxlife 0w20 which happens to have a KV100 of 8.1. Technically speaking it could be classified as a 0w16, a "heavy" 0w16 if you will. I have decided for my 0w20 spec Subaru I will either use a "heavy" 0w20 like Valvoline Modern Engine 0w20 or a "light" 5w30 like Valvoline Modern Engine 5w30 from now on.

My Hyundai GDI has responded well to Valvoline Modern Engine 5w30 and it has an engine spec for 5w20 usage which I will not be going back to due to 5w30 causing the engine to run much quieter and smoother.
 
Messages
350
Location
kansas
A large asterisk must be put next to the thicker oils typically provide better protection and that should state it is assumed your oil reaches operating temperature for an amount of time. I recall it being mentioned in this forum a bit back on how when 5w30 was the new deal in oil that GM said it was alright to run but not ideal for extended highway operation. 0w16 and the xx-20s could be weighed in this light however it is quite likely unless you beat the tar out of your engine you may never know a difference. On the flip side I personally work with a great deal of people that live in the smaller town I work in and only drive 3-4 miles to work everyday. In a case like that where coolant and oil rarely if ever reach operating temperature I couldn't see a good reason why a 0w16 wouldn't be beneficial if used even in engines that spec xx-30. It all has to do with your driving habits and preferences.
 
Messages
710
Location
South Carolina
Thanks for the input!! Yeah I think I’m going to switch to 5w20 in the summer cuz we do get plenty hot and then back to 0w when we get super cold in the winter.

For your older cars are you changing the second value as in the one after the w? Or the first?

cuz the first makes sense to me cuz that depends more on the temperature we live around as in super super cold then 0w is a good bet. Super hot then 5w and 10w is good. However I don’t understand the movement of bumping up from a w20 to a w30
Ford made the switch from w30 to w20 around 2000ish. Theres a thread about it. They also back specced many engines. Take the 4.6L v8 for example. Originally used 5w30 now 5w20 and its tolerance didn't change any. Ford was pushed to use it by Cafe to save gas and it protecs enough so why not? Now as a engine wears the tolerance on then main, rod and cam bearings will increase and oil pressure will drop as a result. One way to remedy this is to use thicker oil. I think the switch was more to save gas than the tolerances of the engines since they didnt change. Most engines can run thicker oils so long as it's not to cold but you can run to thin if the tolerance are to far out of spec. You may notice a noisy engine, lower oil pressure and more oil consumption/leaks.
 
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26,406
Location
PNW
A large asterisk must be put next to the thicker oils typically provide better protection and that should state it is assumed your oil reaches operating temperature for an amount of time. I recall it being mentioned in this forum a bit back on how when 5w30 was the new deal in oil that GM said it was alright to run but not ideal for extended highway operation.
Seems like contradictory statements. So why did GM say 5W-30 was not ideal for extended highway operation when that is the driving conditions that would certainly get the oil to full operating temperature for a long time. Or did you mean 5W-20 in the bolded part ??
 

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45,331
Location
Ontario, Canada
Ford made the switch from w30 to w20 around 2000ish. Theres a thread about it. They also back specced many engines. Take the 4.6L v8 for example. Originally used 5w30 now 5w20 and its tolerance didn't change any. Ford was pushed to use it by Cafe to save gas and it protecs enough so why not? Now as a engine wears the tolerance on then main, rod and cam bearings will increase and oil pressure will drop as a result. One way to remedy this is to use thicker oil. I think the switch was more to save gas than the tolerances of the engines since they didnt change. Most engines can run thicker oils so long as it's not to cold but you can run to thin if the tolerance are to far out of spec. You may notice a noisy engine, lower oil pressure and more oil consumption/leaks.

I think you mean clearances. Clearances are the spaces between parts, tolerances are the adherence to spec for those clearances; the allowable deviation. Clearances haven't changed much for rod and main bearings since the flathead. Tolerances have improved however, as machining has improved and this means that the results are more consistent so deviation from spec is less.

Of course not all Ford engines were back-spec'd to 5w-20. There were certain exceptions, for whatever reason, which I assume had to do with the results of internal testing. The modular, being a relatively recent design, had an extremely rigid bottom-end, which means things aren't moving around and it also had a crank-mounted oil pump, which is an improvement over the cam-driven ones found on the Windsor and other engines. The rigid bottom-end, relatively low specific power density and modern oiling system made it extremely tolerant thinner lubricants, which the engine family was likely tested with quite early on.

I can't remember the last modern engine I've touched that had obviously worn rod and/or main bearings. Even my old Windsor still had fantastic oil pressure with ~200,000 miles on it and was producing significantly more power than stock at the time. All the high mileage HEMI's at work are still being fed bulk NAPA 5w-20. No idea what the oil pressure is on them, as the don't have UConnect to or the digital clusters to easily check, but I suspect it's fine.

Increasing oil pressure by bumping viscosity isn't remedying anything, it's simply masking damage/excessive wear. Maybe it will buy you a few more miles and might quiet that rod knock a bit, but if you are at the point where you have rod bearing noise, that engine is on borrowed time.

The idea is to avoid getting into that situation. Yes, there are a few engines out there that will experience excessive rod bearing wear and need this addressed (BMW, I'm looking at you) but most modern engine designs should last the useful life of the vehicle and go to the wreckers with a healthy bottom-end.
 
Messages
1,022
Location
Massachusetts
I don't see cars having oil related issues so my conclusion is that it just doesn't matter for the vast majority of engines.
You don’t see oil related issues because you own Toyota’s, many of which are not direct injected in your fleet (Except for your newest one). So, you might not have ever had to deal with excessive oil consumption, excessive fuel in your oil, or draining your oil and having it come out looking like hot fudge.

With a Toyota you can drive that thing 10,000 miles and maybe not have to add more than a quart the entire time. With some other mass produced engines driving up and down the highways everyday, you could never do that without dumping 3 quarts of oil in it. And that’s on the low mileage version of those engines...some of those engines when they reach 150,000 miles would be drinking 10 quarts on the way to a 10,000 mile Toyota recommended oil change.

I now own a Toyota - a 2016 Avalon - and I see what all the fuss is about...I see why these things are “recommended“ for 10,000 mile oil changes (not that I’d ever do that) but I see it now. I’m dumping the oil at 5,000-6,000 miles and I’m nit adding oil between changes, the oil is coming out looking like it has 2,000 miles on it. It’s unbelievable...and almost a little bit boring. I’m not used to this.
 
Messages
1,022
Location
Massachusetts
To the OP’s original question. I think people switch to a thicker oil is because as their engine ages it starts to consume more oil. Sometimes that starts to happen at 150,000 miles, sometimes sooner. As the rings begin to wear and as tolerances become larger, they think bumping their oil up to a 5w30, from a 0w20 is the natural way to progress and fight that wear and tear.

Does it help? I don’t think it hurts. I’ve done it. Sometimes it helps a little with consumption, sometimes it doesn’t.

You also have the crowd that believes a “thin” oil harms their engine and that the manufacturer only uses it because of CAFE regulations, and they may be right, but that thin oil is now running through millions of engines everyday, many without any problems whatsoever. So there’s that to consider.
 
Messages
16,544
Location
Upper Midwest
A large asterisk must be put next to the thicker oils typically provide better protection and that should state it is assumed your oil reaches operating temperature for an amount of time. I recall it being mentioned in this forum a bit back on how when 5w30 was the new deal in oil that GM said it was alright to run but not ideal for extended highway operation. 0w16 and the xx-20s could be weighed in this light however it is quite likely unless you beat the tar out of your engine you may never know a difference. On the flip side I personally work with a great deal of people that live in the smaller town I work in and only drive 3-4 miles to work everyday. In a case like that where coolant and oil rarely if ever reach operating temperature I couldn't see a good reason why a 0w16 wouldn't be beneficial if used even in engines that spec xx-30. It all has to do with your driving habits and preferences.
Thicker oils warm up faster than thinner ones, if that is your primary concern why wouldn't you use a 30-grade?
 
Messages
710
Location
South Carolina
I think you mean clearances. Clearances are the spaces between parts, tolerances are the adherence to spec for those clearances; the allowable deviation. Clearances haven't changed much for rod and main bearings since the flathead. Tolerances have improved however, as machining has improved and this means that the results are more consistent so deviation from spec is less.

Of course not all Ford engines were back-spec'd to 5w-20. There were certain exceptions, for whatever reason, which I assume had to do with the results of internal testing. The modular, being a relatively recent design, had an extremely rigid bottom-end, which means things aren't moving around and it also had a crank-mounted oil pump, which is an improvement over the cam-driven ones found on the Windsor and other engines. The rigid bottom-end, relatively low specific power density and modern oiling system made it extremely tolerant thinner lubricants, which the engine family was likely tested with quite early on.

I can't remember the last modern engine I've touched that had obviously worn rod and/or main bearings. Even my old Windsor still had fantastic oil pressure with ~200,000 miles on it and was producing significantly more power than stock at the time. All the high mileage HEMI's at work are still being fed bulk NAPA 5w-20. No idea what the oil pressure is on them, as the don't have UConnect to or the digital clusters to easily check, but I suspect it's fine.

Increasing oil pressure by bumping viscosity isn't remedying anything, it's simply masking damage/excessive wear. Maybe it will buy you a few more miles and might quiet that rod knock a bit, but if you are at the point where you have rod bearing noise, that engine is on borrowed time.

The idea is to avoid getting into that situation. Yes, there are a few engines out there that will experience excessive rod bearing wear and need this addressed (BMW, I'm looking at you) but most modern engine designs should last the useful life of the vehicle and go to the wreckers with a healthy bottom-end.
Yes, Clearance is the correct word.
 

4WD

Messages
15,796
Location
Texas
I think you mean clearances. Clearances are the spaces between parts, tolerances are the adherence to spec for those clearances; the allowable deviation. Clearances haven't changed much for rod and main bearings since the flathead. Tolerances have improved however, as machining has improved and this means that the results are more consistent so deviation from spec is less.

Of course not all Ford engines were back-spec'd to 5w-20. There were certain exceptions, for whatever reason, which I assume had to do with the results of internal testing. The modular, being a relatively recent design, had an extremely rigid bottom-end, which means things aren't moving around and it also had a crank-mounted oil pump, which is an improvement over the cam-driven ones found on the Windsor and other engines. The rigid bottom-end, relatively low specific power density and modern oiling system made it extremely tolerant thinner lubricants, which the engine family was likely tested with quite early on.

I can't remember the last modern engine I've touched that had obviously worn rod and/or main bearings. Even my old Windsor still had fantastic oil pressure with ~200,000 miles on it and was producing significantly more power than stock at the time. All the high mileage HEMI's at work are still being fed bulk NAPA 5w-20. No idea what the oil pressure is on them, as the don't have UConnect to or the digital clusters to easily check, but I suspect it's fine.

Increasing oil pressure by bumping viscosity isn't remedying anything, it's simply masking damage/excessive wear. Maybe it will buy you a few more miles and might quiet that rod knock a bit, but if you are at the point where you have rod bearing noise, that engine is on borrowed time.

The idea is to avoid getting into that situation. Yes, there are a few engines out there that will experience excessive rod bearing wear and need this addressed (BMW, I'm looking at you) but most modern engine designs should last the useful life of the vehicle and go to the wreckers with a healthy bottom-end.
Bingo … and modern SBC’s have a stiff lower end with even the oil pan contributing to the effort … six bolt mains etc … this and the digital manufacturing controls means the (other) word of the day is “concentric“ …
 
Messages
1,240
Location
Texas, USA
It all started for me when Mazda started experiencing a lot of issues with their 2.3T smoking at idle. Bumping them up to a 5W-40 cured it for most customers. I like thicker oil in my turbos for for the seals, and due to the extreme temperatures (1700 degrees) turbos typically see.
 
Messages
372
Location
Scottsdale, AZ
A lot of people think thin oil prevalence is largely due to meeting CAFE standards and there is a perception that there is a big trade off between fuel economy and wear. 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. My other car uses 5w30 so it’s easier buying one grade of oil vs two although I do switch back and forth if Tractor Supply is doing a sale on RGT 0w20.
 
Messages
350
Location
kansas
Seems like contradictory statements. So why did GM say 5W-30 was not ideal for extended highway operation when that is the driving conditions that would certainly get the oil to full operating temperature for a long time. Or did you mean 5W-20 in the bolded part ??
This was in reference to back when 5w30 was new on the block and 40s and 50s were the status quo, “tried and true” weights.
Thicker oils warm up faster than thinner ones, if that is your primary concern why wouldn't you use a 30-grade?
This was in reference to cars that will very rarely if ever see operating temperature in any case not particularly trying to get there faster.
 
Messages
52
QUOTES:
"Thicker oil generally provides better protection. The question is whether or not you need it...." by Jimmy_Russells

"I don’t think we will agree on this topic. It’s a never ending debate" by Artem

"Make your life simple, don't worry about what others are doing in their life." Razor's Edge

I don't want to run anything in my car that will be detrimental to the engine. My car calls for a 0W-20 oil. The service manager at the dealer I bought the car from told me that using 5W-30 will not harm anything and will not void the warranty.
 
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16,411
Location
...
Some people here might be too young to remember when 10w40 or a straight 30 grade was the standard. Then 10w40 ran into problems. CAFE came into existence in 1975 and some time afterwards 5w30 became the standard with much wailing and gnashing of teeth.

This argument has been ongoing since. Nobody is going to change anyone’s mind. In my case I’ve run straight 30, 10w40, 5w30 and now 0w20. I haven’t had any issues with any of them.
 
Messages
182
Location
The Netherlands
This is a never ending discussion, i am an thin oil fan.

I guess most people dont trust the R&D and the tons of money that have been spend for testing when a manufacturer selects its oil.
I have never heard about an engine failing due to having too thin manufacturer oil viscosity.

Even supercars these days also run on 0w20 5w20 etc.. with horsepower levels going beyond 150hp per liter displacement.
 
Messages
1,561
This was in reference to back when 5w30 was new on the block and 40s and 50s were the status quo, “tried and true” weights.

This was in reference to cars that will very rarely if ever see operating temperature in any case not particularly trying to get there faster.
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.
 
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