Update: 5W-30 & Heavier Recommended RoTW (18 Viewers)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

When I used to take my BOSS Mustang 302 to the track, my engine oil temp wasn’t an issue. It was the gearbox oil, which I don’t believe had a cooler. But by then I was usually tired enough to want to take a break myself. Fun car though. More so than my 911 4S.
 
I've always thought the majority of engine cooling was though the radiator/coolant flow? I mentally assigned the oil as a primary source of lubrication.

Is that no longer the case? (Or was it ever that simple?)
 
I've always thought the majority of engine cooling was though the radiator/coolant flow? I mentally assigned the oil as a primary source of lubrication.

Is that no longer the case? (Or was it ever that simple?)
The vast majority is the coolant, yes. But some portion is done by the oil.. which is then cooled by the coolant as well.

One example.. Lots of engines designed to work hard have devices who’s sole purpose is to squirt oil from the galley onto the bottom of the piston as it moves up and down.. this has no significant lubrication function, it is mostly to remove heat from the piston, which is a place that would be very difficult to get coolant to. If the pistons get too hot you get pre ignition and can literally melt them.

That said, oil that is too hot just can’t do its primary lubrication job either. That’s more the point of what I was referring to above..
 
I'm suddenly finding myself slightly more disappointed Mr. T didn't give us the factory option to monitor oil temp even in the advanced PIDs.

I'm probably misinterpreting what you are saying here, but I get engine oil temp on my OBD Fusion App; so it is available with the appropriate (and available) PID - there is just not an OEM dash gauge for oil temp (if that's what you are saying).

IMG_3146.PNG


HTH
 
Soooo can I switch to 5w-30 on future changes but mix in a quart of my leftover Toyota 0w-20 until I’m out of it?
The die hards will say if you mix any different brands/types of oil that sometimes the additive packs don't play nicely together.

I cannot speak to this, but can say I have done it in the past and didn't blow up any of my engines or have any ill effects to speak of in doing so. With that in mind, if you live in a colder climate maybe consider using the 0W stuff in the winter and the 5W stuff in the summer. But again, it likely will not make any difference. HTH.
 
There is no direct measurement of engine oil temperature, it is calculated using data from other sources.
Can you elaborate on what those "other sources" might be? And if they are reliable indicators? And how they end up in a PID?

Any additional info would be appreciated.

TIA
 
Interesting developments for sure with these newer engine designs having tighter margins in design, manufacturing, and cost. Sounds like a bad confluence of factors hitting GM, Toyota, and others.

I don't believe this is cause to rush out and reach for the highest viscosity oils. The 3UR-FE is now a time tested design manufactured over 15 years, utilizing 0W-20 with probably billions of miles. There is no oiling issue with the bottom end bearings and cams in these motors. If there were an oil related liability, it could be the timing chain tensioner which does seem to respond well to added viscosity.

I still think the right oil is 0W-20. An alternative for those that live in the warmer southern regions may be 5W-30. An even better opportunity IMO is 0W-30, as these 0W high viscosity bandwidth oils were real innovations to reduce cold start wear. Reducing wear to the reciprocating assembly, but also less wear on the starter/relay and electrical system (and we know the relay is a liability in the 3UR-FE). 0W-30 generally always starts with a higher grade base oil than many formulations of 5W-30.

Taking viscosity too far is likely to do more harm than good and IMO, -40 weights are too far with almost a doubling cSt kinematic viscosity that will create more heat and load, with lost efficiency and hp. Even in the GM situation, they are still using a 0w-. The added -40 hot viscosity is a bandaid for poorly manufactured motors/bearings that need more hydrodynamic viscosity against low speed pre-ignition. Using the same band aid unnecessarily impacts good running motors.
 
Interesting developments for sure with these newer engine designs having tighter margins in design, manufacturing, and cost. Sounds like a bad confluence of factors hitting GM, Toyota, and others.

I don't believe this is cause to rush out and reach for the highest viscosity oils. The 3UR-FE is now a time tested design manufactured over 15 years, utilizing 0W-20 with probably billions of miles. There is no oiling issue with the bottom end bearings and cams in these motors. If there were an oil related liability, it could be the timing chain tensioner which does seem to respond well to added viscosity.

I still think the right oil is 0W-20. An alternative for those that live in the warmer southern regions may be 5W-30. An even better opportunity IMO is 0W-30, as these 0W high viscosity bandwidth oils were real innovations to reduce cold start wear. Reducing wear to the reciprocating assembly, but also less wear on the starter/relay and electrical system (and we know the relay is a liability in the 3UR-FE). 0W-30 generally always starts with a higher grade base oil than many formulations of 5W-30.

Taking viscosity too far is likely to do more harm than good and IMO, -40 weights are too far with almost a doubling cSt kinematic viscosity that will create more heat and load, with lost efficiency and hp. Even in the GM situation, they are still using a 0w-. The added -40 hot viscosity is a bandaid for poorly manufactured motors/bearings that need more hydrodynamic viscosity against low speed pre-ignition. Using the same band aid unnecessarily impacts good running motors.

Re: 0W-30 versus 5W-30, any concern over there being more additives in the 0W-30 needed to keep the oil from thinning at hot temps? That is, do the additives make the 0W-30 less stable and more prone to shearing and breakdown over time?

I'm going down rabbit holes on BobIsTheOilGuy...
 
Can you elaborate on what those "other sources" might be? And if they are reliable indicators? And how they end up in a PID?

Any additional info would be appreciated.

TIA
I do not have the exact specifics… but imagine inputs include coolant, throttle position, intake airflow/temperature… any parameter that can show an increase or decrease in load. Why Toyota has this is anyones guess… oil change frequency, perhaps? As for Accuracy? The only instance I am privy to, is a 3rd Gen Tacoma that was showing abnormally high oil temps during normal driving. The displayed temperatures made no sense given how the vehicle was being driven. That is but one example, so how do other Toyotas do? Without proof that the system is accurate, I’ll take a sensor that directly measures oil temp. through contact with said oil.
 
Re: 0W-30 versus 5W-30, any concern over there being more additives in the 0W-30 needed to keep the oil from thinning at hot temps? That is, do the additives make the 0W-30 less stable and more prone to shearing and breakdown over time?

I'm going down rabbit holes on BobIsTheOilGuy...

Not untrue, but it needs to be taken in context. At which point it's a non-factor.

Toyota specs 0W-20. Any -30 spec oil will always have more viscosity than what is required regardless of additive wear. -20 wears too and OEMs factor that into their designs.

The worse thing to do IMO is extend oil change intervals (OCIs). Why wait for any breakdown of fluids or additives. Even at 10k OCI, it still won't lose enough viscosity (over -20) to be a factor. Beyond keeping oil fresh which is especially important for modern piston rings, recommended OCIs are also a good time to inspect for any leaks, oil levels, etc
 
Toyota specs 0W-20. Any -30 spec oil will always have more viscosity than what is required regardless of additive wear. -20 wears too and OEMs factor that into their designs.
Well, I disagree that 30 spec is more viscosity than what is required. The 3UR-FE was never designed for 0W20 and was originally factory delivered with 5W30 and even 10W40 in places like the middle east.

Basically -20 spec is less than what is required yet the engineers were arm strung into this by the EPA and Toyota management. Looks like same happened with GM and they are now regretting it. In Australia the 300 series diesel is also requiring more viscous oil. I almost expect the V35A-FTS using -30 or -40 to be a happy camper as well.

For the 3UR-FE the safe bet is synthetic 5W30 and 5k intervals. Perhaps with up to 10k intervals when used a lot on the highways for long trips, without towing that is.
 
Last edited:
Not untrue, but it needs to be taken in context. At which point it's a non-factor.

Toyota specs 0W-20. Any -30 spec oil will always have more viscosity than what is required regardless of additive wear. -20 wears too and OEMs factor that into their designs.

The worse thing to do IMO is extend oil change intervals (OCIs). Why wait for any breakdown of fluids or additives. Even at 10k OCI, it still won't lose enough viscosity (over -20) to be a factor. Beyond keeping oil fresh which is especially important for modern piston rings, recommended OCIs are also a good time to inspect for any leaks, oil levels, etc
Our trip out West starting June 1 will be a 6000 mile loop under tow. There will side trips to who knows where which won't be under tow. All with 0W-30. 0W-20 goes back in when we return in August. We have one small trip to Oregon Inlet National Seashore in the fall but that's an easy one; 300 miles all flat highway.
 
Well, I disagree that 30 spec is more viscosity than what is required. The 3UR-FE was never designed for 0W20 and was originally factory delivered with 5W30 and even 10W40 in places like the middle east.

Basically -20 spec is less than what is required yet the engineers were arm strung into this by the EPA and Toyota management. Looks like same happened with GM and they are now regretting it. In Australia the 300 series diesel is also requiring more viscous oil. I almost expect the V35A-FTS using -30 or -40 to be a happy camper as well.

For the 3UR-FE the safe bet is synthetic 5W30 and 5k intervals. Perhaps with up to 10k intervals when used a lot on the highways for long trips, without towing that is.

I get what your saying and it really doesn't matter if we agree. This interpretation is sporty conjecture when the requirement is crystal clear, to the extent that it is printed on our oil caps. Though I also don't disagree with your 5W-30 conclusion either - for certain use cases and regions in the US.

Context is important when it comes to oil viscosity. It wouldn't be new information to say that predominate ambient temperature has a major influence what oil viscosity to use.

Most of the continental United States is in a different climate region to the areas you quoted. IMO, that's a major factor to what drives viscosity requirements.

1748055417383.png
 
Low ambient temperatures affects cold start wear. In order to make it care free I can see 0W beside 5W and would not recommend 10W except for middle east and a few continuous warm places.

However ambient temperatures is less relevant at operating conditions (around 85 to 105 degr C) when the cooling system is doing its job. Therefore I do not see any issue with using -40 over original -30, yet -20 makes me worried providing less support of the fluid film in the bearings and affects the oil pump pressure negatively, which is likely causing the reported rattle of the timing chain (less pressure is less chain tensioner actuator force).

I remain in the camp of 5W30 being the sweet spot and can get my head around 0W30 or 5W40 and 0W40 considering the 3UR-FE was designed in the late nineties/early two thousands.

Hey, do whatever floats your boat of course.

Source
- Knowledge Centre | Penrite Oil - https://penriteoil.com.au/knowledge-centre/Viscosity/237/what-is-an-sae-viscosity/180
- Note temperatures are in degrees C
1748058264008.png


1748058667764.png
 
Last edited:
Low ambient temperatures affects cold start wear. In order to make it care free I can see 0W beside 5W and would not recommend 10W except for middle east and a few continuous warm places.

However ambient temperatures is less relevant at operating conditions (around 85 to 105 degr C) when the cooling system is doing its job. Therefore I do not see any issue with using -40 over original -30, yet -20 makes me worried providing less support of the fluid film in the bearings and affects the oil pump pressure negatively, which is likely causing the reported rattle of the timing chain (less pressure is less chain tensioner actuator force).

I remain in the camp of 5W30 being the sweet spot and can get my head around 0W30 or 5W40 and 0W40 considering the 3UR-FE was designed in the late nineties/early two thousands.

Hey, do whatever floats your boat of course.

Source
- Knowledge Centre | Penrite Oil - https://penriteoil.com.au/knowledge-centre/Viscosity/237/what-is-an-sae-viscosity/180
- Note temperatures are in degrees C
View attachment 3912923

View attachment 3912924

We agree more than we disagree. It's probably useful for others to really key in on where we live and how that's influenced our conclusions.

You're in Houston Texas where the temps are moderate to hot year round. I similarly would run 5W-30 if I lived there.

I'm in San Diego where the temps are moderate. Though I tow at the extreme end hauling 8k lbs, while traveling through some of the hottest deserts (Death Valley) and cold Sierra mountains, hence my choice for 0W-30.

Most of the rest of the continental US would be better served IMO with factory fill.

I don't see a case for -40 weight oils in the 200-series. That's just throwing away HP and efficiency unnecessarily.
 

Users who are viewing this thread

Back
Top Bottom