What weight oil is best ...

The mixing of the oils would be for peace of mind. The 2tr fe engine was originally designed for 5w30 oil. The oils of the day when the engine was designed (most likely in the late 90's) would often shear back to a 20 wt. It was one of the last engines to be back specified to 20wt. I don't think the 4.0 liter ever was. Did the engineers have cold feet about using an oil that started out as a 20wt? Was the viscosity margin of safety too small?

In Australia, the preferred weight for the upgraded 2tr fe engine in the 2016 Hilux is 5w30 with 5w40 as an alternate. Some would say this is not relevant. I do not have an oil temp gauge or an oil pressure gauge, but I have checked the oil pan temp with an inferred thermometer after towing an utility trailer on a 78 deg. day with the AC on and it read 225. The oil filter read 250 deg. The oil filter reading was most likely fouled by the exhaust heat. I may install some gauges for this. At any rate, I would sleep better at night if the operation viscosity was closer to what the engine was originally designed to use. Even though the engines are very tough and seem to run forever with just about any kind of oil but a little extra viscosity wouldn't hurt.

I believe there have been some changes to the engine this year that indicate the engine is most likely optimized for 20wt. oil. One of which is lighter valve springs which would reduce contact pressures and stress on the oil. Also, the new SN formulations of oil are mandated to have less of the additives that protect the valve train. I am not certain of this so don't beat me up.

 

As far as I know no internal changes were done to the 2TR-FE. Last oil analysis I saw for a 2TR-FE the oil was still within its specified viscosity range for a 5W-30. The change to me was unnecessary as the fuel economy gains are only about 3% during testing.

5W-40 ST rated synthetic diesel engine oil is a great oil to use when modified for higher power or extreme heat. 230 degree pan temp externally read probably means the oil is around 20 to 30 degrees from that measurement. This is a bit high for my liking but the oil is typically good for upwards of 290-325 degrees. At 450 to 500 your at the flash point for most oils. My diesel oil Temps in my Ram usually average 200-210 degrees but the engine does have a cooler in the filter block housing from the factory.

I'm sure the changes to oil viscosity requirements were to meet CAFE standards. An oil analysis would tell you if the oil is protecting the engine or not. Elevated iron and chromium would be concerns showing the lighter grade may not be providing enough of a film to protect the internals.

 

The temp measurements were made with a cheap infrared thermometer. So, take that for what it is worth. Probably not much.

I have found very few UOA's for the 2TR-FE engine and none for 0w-20 with a normal oil change interval. I guess I will have to do one when my engine is broken in.

I would like to install and oil temp and pressure gauges...but where? Tells you a lot about what is going on inside the engine, but then again, ignorance is bliss.

The diesel oils are good but unnecessarily heavy for this engine. Also, as you probably know, they are not good for the catalytic converter.

Does anyone know if Toyota is using low tension piston rings in this engine?

 

Just for everyones information, Walmart isn't one of the participants listed on the Mobil rebate form, so make sure you buy it from a participant.

Edit-- I called Mobil and according to them, Walmart is included and they said you can submit 2 rebates per household, the only caveat is that you must submit it 2 times not just once.

Thanks DGXR, for the heads up on that rebate from Mobil.

Walmart has a rollback on Mobil 1, so after the $12 rebate it's 10.88 for 5 quarts or 21.78 for 10 quarts = WIN WIN!!! stock up now

 

Agree not many out there.

As far as low tension rings I would say no. If they did it would have been when they changed to 0W-20 as the standard fill.
Rotella T6 5W-40 meets the API SM oil spec., so no problem on our trucks as this was the original spec for the 2TR-FE.

 

In the owners manual of my 2014 it says to run 20, can't remember if it was 0w-20 or 5w-20, but it said owners in very hot environments or wanting extra protection can safely run 30. I've been running either 5w-30 or 10w-30 for the last few years. I try to use Royal Purple. So far I've been lucky enough to find a good local sale on it whenever my oil is due.

 

Yeah the oil ATI spec change was done later. 2008 or 2009 if I remember correctly. Then Toyota reduced the weight requirement I believe on the face lifted 2nd gens. I don't remember the exact year. If your truck is a 2.7 2TRFE you can run 5W-30 or down to 0W-20. Run Mobil 1 synthetic after 30k miles just to ensure the rings are seated and after that you will be happy as a clam.

 

Makes me feel better. I just put rotella t4 10w-30 in my 2009 4 cyl and I was wondering if it was too heavy...I am in cali though, so prolly much warmer than where you are at!

 

According to my owners manual they recommend 5W-30 but say 10W-30 is OK to use but should be replaced with the 5W-30 when doing the next oil change. The difference is 5W-30 winter number is lower (5W) so would be better in colder weather, but when at operating temperature they are both the same at 30.

 

5w30 10w30 won't make a difference unless you're below zero: https://goo.gl/images/c4CSXE

 

In Claifornia 10-30 is just fine. Especially in Southern Cali. Hell, in SoCal I wouldn't hesitate at all to run a 10-40 if the engine had over 100,000 miles on it.