Oil Weight

dkmura · Feb 4, 2019

One item not discussed in this thread is that multi-weight synthetic oil is not as thin (or thick), as people might guess. Mobil 1 0-40 FS pours like a 30W oil, but the synthetic base allows it to flow easily at low temperatures. As a racer, I use it to protect my VQ35HR during racing and have the UOAs to back it up. I've tried it in my Titan and the UOA from my VK56DE didn't show it was as effective. I went back to using M1 5-40 Extended and haven't gone back.

matt20 · Feb 5, 2019

So it looks like I'll be going back to 5w30 signature series...cant come to terms with the 0w20 just to save $10 a year on fuel. Thanks guys!

GoVols! · Feb 5, 2019

You wouldn't believe the torture tests these engines go through during development and continued testing during production. My favorite test is when they run the engines at full red line for hours on end. The engine and exhaust system are in a test lab outside the vehicle. The entire exhaust system is glowing bright red from the heat of the engine - very cool to see! If something breaks, they investigate it and countermeasure it.

When the manufacturer lists something like the oil weight, all internal components are engineered with that requirement in mind. For example, the oil jets' spray coverage of the cylinder walls, crank, pistons, etc. Viscosity is taken into account: how quickly does the oil move over the surfaces its' being sprayed on, lubricate it, and remove heat from those surfaces. What's the flow rate and pattern through the oil pump and lubrication system? It's all calculated to provide the best engine performance and durability. If you start messing with those calculations, you may end up on the wrong side of the data and find yourself with an expensive repair. Nissan most definitely will send your oil out for analysis, if you suffer a failure; as would any other manufacturer.

People tend to overthink their maintenance on these things. The manufacturer has already done all the thinking for you - follow the manual.

matt20 · Feb 5, 2019

You make a very compelling argument, and I would love to see one of those tests being performed. I'm sure you are correct in all aspects of flow, heat transfer, etc...but just dont want to sacrifice protection in the name of fuel economy and cafe ratings.
Do they build the engine around the oil, or hope the oil works with the engine? I hope they aren't pulling the wool over our eyes to save a little bit of fuel. After all it's a 400hp V-8 and that's not why I purchased a pick-up.
Thank you for all the infomation!

matt20 · Feb 5, 2019

...also (just speaking out loud) my wife's 2010 lexus rx 350 uses 0w20, yet my friends wifes 2010 Lexus ES 350 (same engine and tranny) uses 5w20. Why is it recommended in one and not the other? Just curious.

LUBECAKES · Feb 5, 2019

GoVols! said:
You wouldn't believe the torture tests these engines go through during development and continued testing during production. My favorite test is when they run the engines at full red line for hours on end. The engine and exhaust system are in a test lab outside the vehicle. The entire exhaust system is glowing bright red from the heat of the engine - very cool to see! If something breaks, they investigate it and countermeasure it.

When the manufacturer lists something like the oil weight, all internal components are engineered with that requirement in mind. For example, the oil jets' spray coverage of the cylinder walls, crank, pistons, etc. Viscosity is taken into account: how quickly does the oil move over the surfaces its' being sprayed on, lubricate it, and remove heat from those surfaces. What's the flow rate and pattern through the oil pump and lubrication system? It's all calculated to provide the best engine performance and durability. If you start messing with those calculations, you may end up on the wrong side of the data and find yourself with an expensive repair. Nissan most definitely will send your oil out for analysis, if you suffer a failure; as would any other manufacturer.

People tend to overthink their maintenance on these things. The manufacturer has already done all the thinking for you - follow the manual.

Smartest reply I've seen yet.
I'm glad you mention the fact that pressurized oil carriers heat away, because that is absolutely the other half of what oil does. These engines are built with tighter tolerances, which requires the use of a lower weight oil. If the oil is too heavy it may not move through the bearings fast enough to prevent an overheated journal.

Bottom line, don't be stupid!
30 weight may work just fine, but why risk it?

slyfur1 · Feb 5, 2019

matt20 said:
You make a very compelling argument, and I would love to see one of those tests being performed. I'm sure you are correct in all aspects of flow, heat transfer, etc...but just dont want to sacrifice protection in the name of fuel economy and cafe ratings.
Do they build the engine around the oil, or hope the oil works with the engine? I hope they aren't pulling the wool over our eyes to save a little bit of fuel. After all it's a 400hp V-8 and that's not why I purchased a pick-up.
Thank you for all the infomation!

I totally understand your thought process and felt the same way. Car makers want to get better fuel economy so they can say in their advertising that their truck gets X mileage. Also car makers are in the business of selling cars if your engine last 300k miles over 10-20yrs they aren't making money selling you a new truck, right?

Tell you what you use 5/30w and I'll use 0/20w and I'll be the first to tell everyone if I ever have a engine related failure. I've never had a engine failure in 15-20vehicles? Granted the most miles I've ever put on a vehicle was 187k 83 Toyota Pickup parents owned since new, 147k Nissan Frontier, maybe 120k on the oldest WRX before we sold it?

LUBECAKES said:
Smartest reply I've seen yet.
I'm glad you mention the fact that pressurized oil carriers heat away, because that is absolutely the other half of what oil does. These engines are built with tighter tolerances, which requires the use of a lower weight oil. If the oil is too heavy it may not move through the bearings fast enough to prevent an overheated journal.

Bottom line, don't be stupid!
30 weight may work just fine, but why risk it?

That was a great reply from GoVols!

slyfur1 · Feb 5, 2019

LUBECAKES said:
Smartest reply I've seen yet.
I'm glad you mention the fact that pressurized oil carriers heat away, because that is absolutely the other half of what oil does. These engines are built with tighter tolerances, which requires the use of a lower weight oil. If the oil is too heavy it may not move through the bearings fast enough to prevent an overheated journal.

Bottom line, don't be stupid!
30 weight may work just fine, but why risk it?

And it's crazy the very tight Toyota engine in my high revving Lotus requires 15/40w synthetic?

LUBECAKES · Feb 6, 2019

slyfur1 said:
LUBECAKES said:

Smartest reply I've seen yet.
I'm glad you mention the fact that pressurized oil carriers heat away, because that is absolutely the other half of what oil does. These engines are built with tighter tolerances, which requires the use of a lower weight oil. If the oil is too heavy it may not move through the bearings fast enough to prevent an overheated journal.

Bottom line, don't be stupid!
30 weight may work just fine, but why risk it?

Click to expand...

And it's crazy the very tight Toyota engine in my high revving Lotus requires 15/40w synthetic?

It's either not very tight or has well over 100 psi hot. Most high revving race engines have looser tolerances due to the higher oil temperatures they see.

matt20 · Feb 6, 2019

Not to beat a dead horse and I will most likely use the recommended weight, but your last 15-20 cars didn't have 0w-20 in them ?

slyfur1 · Feb 6, 2019

matt20 said:
Not to beat a dead horse and I will most likely use the recommended weight, but your last 15-20 cars didn't have 0w-20 in them ?

Yep, only two and they were or are less then 2L 4cyl that advertise great fuel eco. Not a strong powerful 5.6L V-8 like we have in the Titan
BTW did you miss this part of my message?
I totally understand your thought process and felt the same way. Car makers want to get better fuel economy so they can say in their advertising that their truck or car gets X mileage. Also car makers are in the business of selling cars if your engine last 300k miles over 10-20yrs they aren't making money selling you a new truck, right?

matt20 · Feb 7, 2019

I hear ya loud and clear. Let's dig deeper...now that cars last 3 times as longer than they did 20-30 years ago,(definitely longer) now they are 3X's the price and dont tell me it's all inflation and union labor. Are They making 3 times the profit to make up for that longer purchase period? Seriously a decent PU is 50k-70k...makes you think. Sorry, I really do have a life and picking your brain Haha

LUBECAKES · Feb 7, 2019

matt20 said:
...also (just speaking out loud) my wife's 2010 lexus rx 350 uses 0w20, yet my friends wifes 2010 Lexus ES 350 (same engine and tranny) uses 5w20. Why is it recommended in one and not the other? Just curious.

This is most likely due to the advent of 0w20 oil. I'm sure it was a fairly new thing around 2009, so Lexus decided to switch mid-year.
Keep in mind, 20 weight is 20 weight regardless of the first number.

DiddlyD · Oct 9, 2021

blairian said:
Am I the only one here who thinks that it is insane to be using 0W-20 for motor oil? It's practically water...

Anyway, I am sure that some engineers and a bunch of testing is what led them to choosing that oil, but here is my question.

Would I (should I) be better off using a heavier weight oil like a 0W-40 for the Texas heat? My truck, a 2018 Nissan Titan Pro-4X, is black in color. Temperatures will be well into the 100's for months on end, and I will be commuting in heavy stop and go traffic on a daily basis. My concern is that 0W-20 is not going to be heavy enough to protect the motor....

Thoughts?

I'm going with 5w30 I live in AZ. I have a Toyota Sienna 2014 (mini van) says 0W20 too. 0W is for extreme cold weather to -40 F and the 20 stays thick enough to cover lubricating up to around 58 F outside temps. Good for winters back east! I could even go to the 10W in AZ but 30 will give up to around 90 F (there is a 5W40 too but I would only use for the summer only). I am retired so just made mostly short trips so 5W30 may be sufficient. I have read the 0W20 and now 0W16 are about meeting environmental requirements.

dkmura · Oct 10, 2021

I'm retired as well, but also have 30+ years in motorsports experience with oil viscosity. The blends with multi-weights like Mobil 1 FS 0-40W offer protection at either end of the temperature spectrum, but still pour like a 30 weight oil. That allows my Colorado based race engines to run at max RPM in both cold springtime races as well as the heat of summer with minimal wear.

titan14 · Oct 10, 2021

DiddlyD said:
I'm going with 5w30 I live in AZ. I have a Toyota Sienna 2014 (mini van) says 0W20 too. 0W is for extreme cold weather to -40 F and the 20 stays thick enough to cover lubricating up to around 58 F outside temps. Good for winters back east! I could even go to the 10W in AZ but 30 will give up to around 90 F (there is a 5W40 too but I would only use for the summer only). I am retired so just made mostly short trips so 5W30 may be sufficient. I have read the 0W20 and now 0W16 are about meeting environmental requirements.

i agree there are CAFE requirements likely driving this, but many people live in very hot climates, myself included, and have been using 0W20 for hundreds of thousands of miles and have not seen increased engine wear. The viscosity is important for the variable cam timing to function properly, another reason to stick with whats recommended

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