5W20 VS. 5W30 VS. 10W30

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Considering what to run in my 03 V6 Toyota Highlander which is a non-sludge year engine.

With my limited oil knowledge, correct me if i am wrong but the 5w20 will have the best fuel economy and cold starts and the 10w30 will have the best thermal stability. So would a 5w30 be the best of both worlds? The engine in question has been ok'd by Toyota for 5w20 use.
 
5W-20 offers an increase in fuel economy and to this point have shown to be pretty good oils, plus they offer better low temperature performance.

5W-30 offers good cold weather performance and good high temperature protection to an extent but have not shown to be notably better than 5W-20 oils in applications where 5W-20 is reccomended.

10W-30 offers the best high temperature performance, but at a significant cold weather performance penalty and to an extent startup wear penalty from what I have heard.

If it is spec'd for 5W-20 just use 5W-20, if for 5W-30 use 5W-30. I wouldn't use 10W-30 except in the summers in most of Canada.
 
I'd go with MG's comments on this, with the following thoughts. Over the years here, I've become convinced that each of us have enough unique facts in our usage patterns that general advice is good only as a starting point. To take it to the n-th degree, you'll have to do several UOAs to see how your oil choices perform in your environment, under your usage conditions. You might try a few different oils, and see how they do for you, with the OEM recommendations as a starting point. Be patient, and let us know how it works out if you decide to try this path.
 
SAETemps.jpg
 
So according to this chart. Would 5w30 and 10w30 be identical when it comes to summer performance and the only clear advantage would be 5w30 in the winter?

As the chart does not contain 5w20, would the maximum temp range be in the 25c to 30c range?
 
Originally Posted By: byez
So according to this chart. Would 5w30 and 10w30 be identical when it comes to summer performance and the only clear advantage would be 5w30 in the winter?

As the chart does not contain 5w20, would the maximum temp range be in the 25c to 30c range?



My take is that 5w30 always has the advantage over 10w30, unless your engine shears oil alot, or has very few cold starts...by, cold, I mean anything significantly less than operating temperature....
 
Originally Posted By: 02zx9r
SAETemps.jpg



Sorry, but I think that graph is meaningless. My truck is spec'd for 5w20 in all weather. But according to that graph, I should be running straight 40 weight..??.. (yes, my temps are petty much +50*F all year).
 
Your engine has a thermostat to try to keep it close to the same temperature all the time when it is operating, roughly 195 degrees Fahrenheit, and it will only exceed that when the radiator's cooling capacity is exceeded. Typically 30 weight oil is at about 13 cSt at that temperature, and 20 weight oil is about 10.5 for viscosity.

The thinner oil is made up for by increased oil flow as well, and in most conditions 5W-20 is acceptable.

If you tow, or your engine regularly runs higher temperatures, you may require the additional protection of a 30 weight, and if the engine is specified for a 5W-30 oil (which it most likely is) it is the safest bet for all season performance.
 
the chart is somewhat old but is the only one I have at this time. If anyone has an updated one i would like to see it
 
I forget who it is either patman or gman that is running straight 30 weight in his 300M, no problems. Wont shear as much as the multi-weights
 
I agree that these generic oil temp charts are basically junk.
If you look at the chart suppplied by your auto manufacturer,
you will see what oils to use for given temp ranges. These can be found in your owners manual and are spec'd for conventional oil. They typically recc one grade but allow others under certain circumstances. Buy the cheapest brand name you can find that correlates with your expected temp range and change it according to the manual. Very simple really .

SS
 
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I would take the 10w30 as the most robust oil, the closer you keep the numbers, 10 to 30, 5 to 30, 5 to 20, the less modifiers and better protection aginst shearing. 10w30 is all of a sudden, in the last couple of years labeled a gear oil by most. I would guess 70% of the cars on the road are running on 10w30, no matter what they are spec'd on. All the quick lubes run this as well as alot of home mechanics. So far all the super high milelage cars( a million miles) have been on thicker oils such as 10w30 or 20w50. Neither a 5w20 or a 10w30 is going to cause overnight failure in any engine. That said in my opinion, 10w30 is still the best choice for any and all cars.
 
Generally speaking Pman is right. Unless your manual states otherwise you can probably use 10w-30 in any engine and be ok.
I consider it to be the default oil when unsure of what to use.
My Honda manual says I can use 10w-30 down to 20F, however it says 5w-30 can be use year round for all temps. So I use the 5w-30 because the winters here can see temps down to 0F. I realize that 10w oils are good down to 0F, however I want the faster lube provided by 5W in the lower temps. I would have no issues running 10w-30 in the summer however.

SS
 
I think you are better off with a 0w or a 5w. It is stated that 70% of wear occurs with the cold start,so I think a lower cold viscosity might result in less wear. Just my .02.
 
Originally Posted By: FZ1
I think you are better off with a 0w or a 5w. It is stated that 70% of wear occurs with the cold start,so I think a lower cold viscosity might result in less wear. Just my .02.
unless the temps are so cold that the oil has trouble being pushed into the pump,thing of sucking a thick milkshake through a straw ,the wear comes from the pistons being oval ,the rings not sealing well,a richer mixture the heat activated oil additives not at their best temps etc, not the viscosity of the oil.
 
Originally Posted By: bamorris2
Originally Posted By: 02zx9r
SAETemps.jpg



Sorry, but I think that graph is meaningless. My truck is spec'd for 5w20 in all weather. But according to that graph, I should be running straight 40 weight..??.. (yes, my temps are petty much +50*F all year).
5w/20 is an epa mandate.
 
Originally Posted By: Steve S
Originally Posted By: bamorris2
Originally Posted By: 02zx9r
SAETemps.jpg



Sorry, but I think that graph is meaningless. My truck is spec'd for 5w20 in all weather. But according to that graph, I should be running straight 40 weight..??.. (yes, my temps are petty much +50*F all year).
5w/20 is an epa mandate.


Maybe so, maybe not... But I have yet to see any solid/reliable report show that 5w20 provides less protection than any other oil (given that 5w20 is spec'd).
 
Originally Posted By: Steve S
Originally Posted By: FZ1
I think you are better off with a 0w or a 5w. It is stated that 70% of wear occurs with the cold start,so I think a lower cold viscosity might result in less wear. Just my .02.
unless the temps are so cold that the oil has trouble being pushed into the pump,thing of sucking a thick milkshake through a straw ,the wear comes from the pistons being oval ,the rings not sealing well,a richer mixture the heat activated oil additives not at their best temps etc, not the viscosity of the oil.


Agreed.
 
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