0W-40 engine oil
 

Took my 86 in for the 15000km service recently and when I checked the dashcam for any joyriding, I got servicing/car washing footage instead! It seemed they just left the key in ACC and forgot about it.

I noticed the engine oil they used was Castrol 0W-40. Now this means higher viscosity at higher temperatures, compared to the recommended 0W-20 but more engine wear and lower fuel efficiency due to the thicker oil. The question is, should I bring up this issue with the dealer/service centre?

Yes, I would.

They probably carry 0W-40 as the bulk fill for European cars, but they should carry 0W-20 for cars that spec it. Even your Edge 5W-30 meets ACEA A3 specs so it has a High Temp High Shear of 3.5 or higher (and likely a thick kinematic viscosity) and would behave much like a thin 40 grade.

-Dennis

I assume this was done at a Toyota dealer so there wouldn't be any European cars about? I'd be double checking what they put in & if it was 0w-40 as you suspect from your cam then I'd be making a big noise about it. The service schedule specifically say use only 0w20 or 5w30 but 0w-20 is preferred.
Does the car feel sluggish after the service? I tried Edge 0w-40 in my Altezza 3SGE which is specs for 5w-30 & it made a noticeable difference so I'd hate to think how it would negatively effect the performance of an engine specd for 0w-20.
If the dealer can't/wont source you Castrol 0w-20 then I'd be looking up my nearest Motul retailer

It was definitely 0W-40 (letters were clear as day on the cam).

Right now I'm finding the engine feels like it's actively engine braking when I'm cruising. For example usually I can cruise on 5th at 60km/h without any throttle input on a nice flat road. Now the car just slows down until it bogs and feels like as if I'm in 3rd or 4th. I don't know whether it's because of the thicker oil or because I'm running E85 (less energy so rpm falls faster).

I'll probably let the dealer know and see if they can do something about it. Worst case, I'll buy 2 cans of 0W-20 off them (which I did for my first oil change) and do the change myself.

They should change it back to 0w-20 free of charge, their mistake not yours. Have a word to the service manager.

In the U.S. having one dealer selling up to 5 or 6 different cars (U.S., Japanese, European) isn't all that unusual, so I though that might be the case here. The lazy ones will just carry one or two bulk fill oils even if they have 3 or 4 different oil requirements (usually going with the thickest oil for all cars).

enouf, I do agree that they should just change it to 0W-20 and not charge you! You're running an oil that is two grades above the recommended viscosity.

-Dennis

Get them to put the right stuff in.

HOWEVER

The only difference between 0w-20 and 0w-40 is that 0w-40 has a higher ambient viscosity. When at operating temperature, the viscosity are negligible compared to one another.

http://www.bobistheoilguy.com/motor-oil-109/

All of Bob's stuff is a good read.

Got closure on this mishap.

They investigated and found the techies had been using an old (but clean) 0W-40 container to transfer the 0W-20 from drums to the car. They said engine oil are on "guns" but in the case of the 86, they keep 0W-20 in drums so they had to use the old container to get it over, hence the confusion.

False alarm guys, my bad. But never hurts to be vigilant =D

I wouldn't say that at operating tempurature the viscosity of a 40 grade and a 20 grade are negligible . In fact, they are very different in a car that specs a 0W-20.

The kinematic viscosity at 100C for the Castrol Edge 0W-40 that the OP thought was in his engine is 12.79 centistokes at 100C. While this is not a very thick 40 grade, the High Temp High Shear (measured at 150C) is at least 3.5 cP in order to meet European ACEA A3 and Euro manufacturer requirements. A 20 grade will have an HTHS of 2.9 or lower.

This first number on the bottle represents the apparent viscosity when measured at -35C. http://www.pqiamerica.com/coldcrank.htm
Above that a 0W-40 will be thicker and even at freezing temps the 40 grade will be considerably thicker. Click around on bobistheoilguy and look for the viscosity calculator. If you enter the kinematic viscosities for NZ Castrol 0W-40 (75.7 and 12.79) and U.S. M1 0W-20 (easier to find the specs on this oil; 44.8 and 8.7), you'll see that at 0C the Castrol 0W-40 is nearly twice as thick as the M1 0W-20 (324.4 cst's vs 635.3). Of course, they are closer together when the oil gets to 100C, but I wouldn't want to run a 12.79 or thicker oil in a car that specs 5.6 to 9.29 cst's.

-Dennis

So, um. OK. Thanks for reiterating what I said, Dennis. As I said, at ambient temperatures, 0-40W has a higher viscosity.

So, um. OK. You're welcome. :)
You said that the 40 grade is thicker but at operating tempurature the difference is "negligible ". My point is just that it's not negligible.

-Dennis

You're handwaving away the pretty significant difference in chemistry. A 40-point viscosity spread is pretty extreme and requires a LOT of friction modifier - but you'd know that, right? Since you read Bob.

So I read chapter 8 and it says.

There is one more thing. A 20 grade oil is not half as thick as a 40 grade oil. The real scale is more like the oils having an absolute thickness of 108 and 114. Now it can be seen that the 40 grade oil is only around 10 percent thicker than the 20 grade oil. The difference is not that much at operation but at startup the difference is significant. Pressure / flow dynamics go along with this 10 percent figure. A 30 grade oil should be thought of as having an absolute viscosity of 110 and a 50 grade oil has an absolute viscosity of 120. I am talking about the viscosity at operating temperatures.

However I find that confusing because when I compared a 0w-20 oil with a 0w-50 oil the viscosity at operating temp 100c was 6.7 and 18.7 respectively. Surely that makes the 0w-50 almost 3 times as viscous at 100c than the 0w-20 oil?

What you're saying is that a 0w40 oil has less lubricating properties than a plain 40w Right? Because of the added friction modifiers there is actually LESS lubrification content.