You actually were doing something special ... Castrol GTX was THE definitive oil before synthetics took over the world ... changed every 3,000 and my engines lasted forever with absolutely no sludge buildup ... unlike Pennzoil or Quaker State ... the absolute worst, with horrific sludge build-up as were all of the Pennsylvania based products back in the day.

 

Pretty sure the operating temp of the engine is the same in either location, assuming the cooling system is working properly. Yours will just get up to that temp quicker with a head start.

 

With only 320 miles on my 2021, I have asked the same question to several Lexus dealership mechanics and get 2 different answers on when to change the break-in oil. Most say best to do it around 1-2k to remove and metal shreds and stay with the 0-20w. One manager said, do not change it before 5k as the break-in oil is special oil that Lexus puts in and it needs to be there for 5k miles. So, no real answer from what I can find out.

 

Modern cars no longer use "break-in oil" ... so the manager referenced needs to step into the 21st century.

 

A (close to) constant coolant temperature (gauge reading) is not an indicator of the amount of heat energy that is being absorbed and dissipated by both the engine coolant and the engine oil in circulation. Your pretense has absolutely no engineering logic.

 

Your use case for the truck should be a factor in oil selection. If you are just driving to work or heading to the grocery store, 0W-20 works great. If you are towing in the Rockies near max like I do, spinning lots of RPM's and generating a lot of heat, finding a heavier duty oil is probably a good idea.

RPM's are really what tell you the stress on the oil. The shear stresses in the bearings and piston rings will be higher at higher rpm. The oils high-temp/high shear strength helps determine how good that particular oil is at keeping metal things separated in those high stress locations. Heavier oils generally have higher HTHS. A US based 0W-20 might have an HTHS of 2.7 while a US Based 5W-30 has an HTHS of 3.2. A Euro 5W-30 is more like a 3.5. 0W-40's start getting to the 4.0 range. So the heavier oils have the ability to keep the metal parts separated in more extreme conditions.

This is why you see track oriented cars running 50 weight oils. Take the mustang 5.0 for example. A regular old mustang 5.0 is spec'd with 5W-20. A mustang 5.0 with the track pack has the same motor but is spec'd with 5W-50. Running a heavier oil in an engine isnt gunna cause it to blow up. It generally just causes increased drag from pumping heavier and maybe a little more wear from a very cold start.

So basically, if you expect to run your engine hard and hot, running a heavier oil is a good idea.

 

[QUOTE=skrypj;11045911]Your use case for the truck should be a factor in oil selection. QUOTE]

^ Agree with above, with "use case" also needing to consider ambient operating temperatures. Relative to the cold start wear consideration, 0w and 5w are not far enough apart to be material unless living well North specifically during in the winter months ... so bumping from 20 to 30 (0w-20 to 5w-30) is not a giant leap worth any level of consternation, while providing extra protection under load or high(er) heat conditions. Toyota recommended oil (weight) for non-US countries for the exact same engine provides engineering insight ... placing engine longevity as a priority over regulatory influence that views engine longevity as a secondary consideration to a fractional improvement in fuel economy.

 

True, the gauge doesn't indicate heat throughput. But if your cooling system is successfully dumping that heat it doesn't matter.

My point (that I didn't explain very well) is that ambient air temperature is pretty much irrelevant for oil choice for an engine at normal operating temperature. The amount of work an engine does has MUCH more impact on heat generated, as others have pointed out, and if your engine is working near the margins of the cooling system capability then your oil choice may be impacted.

 

I picked up a case (5 filters) off Amazon the other day. All seems legit except that ever filter inside the boxes is stamped with a # that differs from what's on the box. Shouldn't they match? Can someone who purchased an OEM oil filter from say the dealer or an auto parts store confirm? Thanks in advance!

 

I think you're ok... this Toyota site shows that filter element within that kit part # you ordered: https://parts.olathetoyota.com/oem-p...ter-04152yzza5

superseded data for oil filters in these listing as well: https://parts.toyota.com/p/Engine-Oi...4152YZZA5.html

https://www.clublexus.com/forums/gx-...change-17.html

 

Rest-of-World ... from Owners Manual ... Toyota Oil Recommendation for the GX460 Engine ...

 

I think the part # on the box references the "kit" made up of the filter element, and whatever o-rings and other stuff were in the box.

 

Looks to me that 5w-30 covers all of the bases ... and 10w-30 or even 15w-40 for the more Southern or West Coast climates.

 

Same here but I bought the YZZA3 version to avoid warranty issues. Also had a similar freak out after seeing a different P/N printed on the element. As the other members kindly pointed out, you're good.

 

Even here in Utah at 6500', its rare to see 0F, and its usually only for a couple of hours in the early morning.