Oil weight

[RicStyx]

I'm curious as to what weight of oil everyone uses. On my last service, toyota used 15W-40 which came as a shock. Now the book states it can be used but either 0W-20 or 5W-20 is also acceptable which I feel is a far better weighted oil for a small engine and according to the temperature range application can do more. What is everyone's opinion and what do you use?

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[dogsridewith]

Ask "toyota" why 15w-40 was used on this oil change. (please bring answer here. I don't like giving up ANY engine life/protection for the efficiency gain of thin oil...understanding that too thick on cold winter starts isn't good for the engine either.)

[RicStyx]

When I asked they stated it was the general based oil they use on the smaller petrol engines, they also stated due to our climate it is the right oil to use. However, if i follow the weight guide in the book, the range for lighter oils have more versatility than the heavier used in my car. Temperatures rarely drop below 10 degrees here and its for a short amount of the year, otherwise its in the mid 20s to 30s.

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[hotracer_05]

I run 5W-30 Full Synthetic

[toad]

Originally Posted by hotracer_05

I run 5W-30 Full Synthetic

same here.

[NYC-SE]

Originally Posted by hotracer_05

I run 5W-30 Full Synthetic

Originally Posted by toad

same here.

Me too.

[dogsridewith]

I'd then ask why 15w-40 rather than the common 10w-40.
(10F or 10C?)

[tmontague]

5w30 full syn during the summer at the track (260 degree oil temps and pressure is fine) and I run 0w30 full syn during the winter.

The problem on forums when discussing oil now a days is that there are many people who have been around cars for a couple decades or more but oil technology has come leaps and bounds in the past 10 years. This leads to much advice not necessarily being correct in today's world although it was smart not a long while ago.

Case in point - thicker oils offer more protection. Not necessarily true anymore although this would have been the case back when single weight and dyno oils were the main stay.

There are a tremendous amount of studies published online that have been performed on new full syn oils of varying weights and their effect on engine components. Problem is these are not always known and are not easy to read not are they fun to read so they often get passed over.

Take home point - run a UOA if you want to know how your oil stacks up. This is how I know I can run 20,000km oci's on my oil with track use

[suprf1y]

Originally Posted by tmontague

5w30 full syn during the summer at the track (260 degree oil temps and pressure is fine) and I run 0w30 full syn during the winter.

The problem on forums when discussing oil now a days is that there are many people who have been around cars for a couple decades or more but oil technology has come leaps and bounds in the past 10 years. This leads to much advice not necessarily being correct in today's world although it was smart not a long while ago.

Case in point - thicker oils offer more protection. Not necessarily true anymore although this would have been the case back when single weight and dyno oils were the main stay.

Take home point - run a UOA if you want to know how your oil stacks up. This is how I know I can run 20,000km oci's on my oil with track use

I call that the small block Chevy factor. I thought that the access to information that the internet would bring would ferret that out but it's spread to the internet from the magazines and actually become much much worse.

So tell me more about your 20k oci's. I've done it in the past despite predictions of doom and gloom but have no personal experience with these motors

[tmontague]

Originally Posted by suprf1y

I call that the small block Chevy factor. I thought that the access to information that the internet would bring would ferret that out but it's spread to the internet from the magazines and actually become much much worse.

So tell me more about your 20k oci's. I've done it in the past despite predictions of doom and gloom but have no personal experience with these motors

I just used Mobil1 0w30 and slowly increased my OCI each time as per Blackstone's recommendations. I eventually got to above 20k km but ended up switching to a 5w30 Pennzoil ultral platinum due to track use and summer temps, it has a slightly higher HTHS rating than the Mobil1 (IIRC). Since I'm no longer commuting to Toronto for school my mileage is much lower so I don't accumulate the mileage like I used to so I haven't pushed a long OCI. The last recommendation on that oil was to try 21k km.

Keep in mind my last summer OCI was just over 13k km and it had over 800km's of track use on it. Based on conventional wisdom this is a very extended OCI and would not be recommended. We will see when I get the analysis back. This will help me make my decision of what oil and OCI I will use next season.

It should be noted that on the Mobil1 I was driving about 80% (at the least) on the highway and commuting very early in the morning and late at night so i was missing rush hour. At the time when using that oil I was also new to driving on the track and was not pushing my car nearly as hard as I do now. It is still very useful info for the everyday commuter.

The oil sample I'm waiting on now will be much more useful for those that track their cars, but I haven't received it yet.

I'm a numbers and empirical evidence guy so I use real life data and various studies published on oil. I'm not saying that anecdotes are useless, but in the hierarchy of evidence anecdotes fall much lower when good quality empirical evidence is available. This obviously changes when an engine builder is building you an engine that is different than factory specs as most studies are published on factory engines. But for people on a factory engine and factory tune, focusing on oil temps for their driving type will be the best way to determine the correct viscosity oil as well as UOA's to determine how the oil is holding up.

The problem is the internet can make a relatively small voice sound very popular. You see this all the time on car forums where one person posts about a product or part they used that may have failed for any possible reason. Other's read this and then they go on other forums and claim how the part is crap even though they themselves have never had any experience with said product. Now it looks like the consensus is that the product is garbage even though many real world users may be successfully and happily using the product.

Others may disagree with my views on engine oil, but I am not particularly in agreeance with any particular camp whether it be, thicker is better, thinnest is best or just use what the manufacturer recommends as they know best. My view tends to lend itself to certain aspects of each of those opinions.

The 1nz is very conservatively tuned from the factory and is not really hard on engine oil. They are robust engines, typical of a toyota engine. As long as you either run the factory filter and change it every 8k km, or run a high mileage filter, you should be fine with extended OCI's. If you want to be sure than run a UOA with a TBN to see how well the oil is holding up. In very cold climates where trips are more short in duration or city driven, a 0w20 oil in the 1nz would keep the pressures within spec of the called for 5w30. In normal driving in the summer or long trip winter driving a 0w30 would be fine and fall within what the factory calls for.

Engines can tolerate varying viscocities (hence why Toyota calls for different viscocities for the same engine in different parts of the world) and often times engine durability and protection is not the main reason manufacturers choose a certain viscocity (CAFE standards, anyone?) My recommendation is to run what keeps the engine within pressure specs based on your type of driving. if you live in a cold climate than use a 0w over a 5w to make startups easier.

Keep in mind the 2zr has roller rockers where as the 1nz has a flat tappets like design. technically the 2zr had less friction at this area. That said, when I removed the valve cover on my 1nz with 175k km on it, it looked brand new and the cams and valve caps were completely mark free.

[IllusionX]

Middle East and African countries seem to use quite heavy weight oil. 10w50, 15w40 is regularly seen being used.a

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[rayfloyd170]

Originally Posted by IllusionX

Middle East and African countries seem to use quite heavy weight oil. 10w50, 15w40 is regularly seen being used.a

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I am in Saudi Arabia and run using full syn 5w30 all year long from summer reaching average 45 deg C and winter at ~5deg C... This is also what is stated in my manual... But toyota service center dont have the fully synthetic 5w30 available hence i used 3rd party brand lube...

[JDJanitor]

I am lucky , I can get any weight I desire, right now I'm using 5w-30, I don't think I am sacrifice any engine e life over using a 10w30 or 10w40

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[IllusionX]

Originally Posted by JDJanitor

I am lucky , I can get any weight I desire, right now I'm using 5w-30, I don't think I am sacrifice any engine e life over using a 10w30 or 10w40

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I don't think you'd sacrifice engine life. You'd be better protected with heavy weight on a 115F cold start than with 5w30.

I'm sure you don't see this kind of temperature in CT.

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[JDJanitor]

Luckily, I don't see those temps. I see the 90's but that's about as high as it goes.


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[scylla]

Here in the US, 15w40 is the commonly used weight for big truck diesel. I'm not even sure a 15w40 is sold here that doesn't have the diesel engine additive package.
It's not an oil formulated for cars. You can use 15w40 for a car, but it isn't ideal.
Of course being OP is in S.A. could change all of that.

[dave mac]

Hey, I have an '07 h/b, a/t, w/86k mi. Does anyone use 0W-20 on the 1.5 1NZ-FE in cold weather? I've used 0W-30 and syn 5W-20 in winter, but not 0W-20 yet. Car is not run hard, 'hypermile' type driving 100% of the time, if that matters. Thx!

[tmontague]

The 1nz in NA iirc specs 5w30, 0w30 can be used without issue, 0w20 would also likely be fine but isn't technically what the manual specs.

If your focus is fuel efficiency then it may be of slight benefit to you.

I use various oil weights in my 2zr engine even though it calls for 0w20 in NA (calls for a different weight in warmer climates). I do this based on my oil temps as a stock engine operating temps for oil are about 220F summer and 180F winter.