Recommended Oil Viscosities

[craigq]

Help me understand why thicker oil is appropriate for warmer ambient temperatures? I say this because once the engine is at full operating temperature, it doesn't matter much what the outdoor ambient temperature is.

FWIW the oil temperature gauge on our Forester XT never gets above 90*C in the winter months, whether city driving or highway runs. In the summer months it is routinely above 90*C. Might have something to do with that, ambient temperature plays a role.


Edit: If you check out kinematic viscosity at various temperatures it's possible that an xW-20 might be equal in centistokes at 80*C to an xW-30 at 100*C

https://wiki.anton-paar.com/en/engine-oil/

2nd edit: 30's at 90*C are pretty much equal in viscosity to a 40 at 100*C, about 11-12. 30's at 100*C are much thinner, 8-9.

3rd edit: couple of different charts available too online showing spec behaviour of oil weights at temperatures:

https://www.pumpsandsystems.com/site...Heinz-fig2.jpg
from : https://www.pumpsandsystems.com/bear...aring-function

etc.

[Mark]

Help me understand why thicker oil is appropriate for warmer ambient temperatures? I say this because once the engine is at full operating temperature, it doesn't matter much what the outdoor ambient temperature is.

I can't speak for anyone else. The W on oil doesn't stand for weight. The W stands for winter. I am old enough to remember my dad using straight 10W oil during the winter months & straight 30W oil during the summer months. Thinner oil is better for winter and thicker oil is better for summer is forever stuck in my brain I guess.

Personally, I think 0W-20 synthetic oil is a great winter oil. It's super thin! It's also recommended year round in the U.S. for many vehicles now. I cut firewood today. Bar oil is similar to 30W oil. It took forever to pour out of the jug, because it was colder today.

My first experience with 0W-20 synthetic oil is my 2011 Subaru Forester. Thanks to class action lawsuit against Subaru, I basically had a new engine installed @ approximately 90,000 miles. My Forester spent 6-weeks at the dealership this past fall, & I was provided a free loaner (2018 Outback) during this time. I wasn't charge anything, & I didn't buy this Forester from the dealership that did the work. Thus, I am not really complaining here.

An oil consumption test involved the dealership doing an oil change, and you return the vehicle somewhere between 1,200-1,600 miles. I brought it back @ 1,000 miles, because it had already burnt more than a quart of oil. I would have been adding approximately 6 quarts of expensive synthetic oil between oil changes. Why bother changing oil at that rate? Just change filters, right? A Forester requires 5.5 quarts. A 5-quart jug isn't enough to do an oil change by the way. I am somewhat complaining now!

I never had a vehicle (using conventional oils) burn oil at this rate before. I realize this is a design flaw (bad piston rings most likely). Replacing piston rings wasn't fixing the problem, however. Subaru soon discovered that. The entire short block of the engines are being replaced now. When I picked up my Forester 6-weeks later, they had 7 more engines to replace at the time.

This is problem is not just isolated to Subaru. My dad's GMC Terrain (4-cylinder) had its entire engine rebuilt free of charge, too. The Terrain came with a 150,000 mile warranty afterwards. Subaru is not offering that.

I do my own oil changes. I do them ahead of schedule. Subaru dealers suggest 7,500 miles, & I have always done 6,000 miles oil changes with this car. On a positive note, I was never asked to show my maintenance records.

From personal experience, I am still somewhat skeptical of lightweight engine oils being declared awesome! My hope is that my 2017 Mirage will erase that in the next 5-10 years.

One forum member has well over 200,000 miles on his Mirage. It's approaching 250,000 miles. He receives free oil changes every 5,000 miles from the dealership, and it appears they may be using 5W-30 oil. His only problems have been A/C related.

Another forum member claims to use Mobil 1 0W-20 synthetic oil, & his engine is starting to burn oil after 100,000 miles. I take a mental note of these things, because I am still skeptical of lightweight synthetic oil being declared great! I do believe lightweight oil helps in the mpg department, & that is the driving force behind all this.

Sidenote: Subaru Foresters are highly recommended by Consumer Reports. Why is that? Some are burning almost as much oil as a 2 stroke engine.

[Eggman]

I can't speak for anyone else. The W on oil doesn't stand for weight. The W stands for winter. I am old enough to remember my dad using straight 10W oil during the winter months & straight 30W oil during the summer months. Thinner oil is better for winter and thicker oil is better for summer is forever stuck in my brain I guess.

Personally, I think 0W-20 synthetic oil is a great winter oil. It's super thin! It's also recommended year round in the U.S. for many vehicles now. I cut firewood today. Bar oil is similar to 30W oil. It took forever to pour out of the jug, because it was colder today.

My first experience with 0W-20 synthetic oil is my 2011 Subaru Forester. Thanks to class action lawsuit against Subaru, I basically had a new engine installed @ approximately 90,000 miles. My Forester spent 6-weeks at the dealership this past fall, & I was provided a free loaner (2018 Outback) during this time. I wasn't charge anything, & I didn't buy this Forester from the dealership that did the work. Thus, I am not really complaining here.

An oil consumption test involved the dealership doing an oil change, and you return the vehicle somewhere between 1,200-1,600 miles. I brought it back @ 1,000 miles, because it had already burnt more than a quart of oil. I would have been adding approximately 6 quarts of expensive synthetic oil between oil changes. Why bother changing oil at that rate? Just change filters, right? A Forester requires 5.5 quarts. A 5-quart jug isn't enough to do an oil change by the way. I am somewhat complaining now!

I never had a vehicle (using conventional oils) burn oil at this rate before. I realize this is a design flaw (bad piston rings most likely). Replacing piston rings wasn't fixing the problem, however. Subaru soon discovered that. The entire short block of the engines are being replaced now. When I picked up my Forester 6-weeks later, they had 7 more engines to replace at the time.

This is problem is not just isolated to Subaru. My dad's GMC Terrain (4-cylinder) had its entire engine rebuilt free of charge, too. The Terrain came with a 150,000 mile warranty afterwards. Subaru is not offering that.

I do my own oil changes. I do them ahead of schedule. Subaru dealers suggest 7,500 miles, & I have always done 6,000 miles oil changes with this car. On a positive note, I was never asked to show my maintenance records.

From personal experience, I am still somewhat skeptical of lightweight engine oils being declared awesome! My hope is that my 2017 Mirage will erase that in the next 5-10 years.

One forum member has well over 200,000 miles on his Mirage. It's approaching 250,000 miles. He receives free oil changes every 5,000 miles from the dealership, and it appears they may be using 5W-30 oil. His only problems have been A/C related.

Another forum member claims to use Mobil 1 0W-20 synthetic oil, & his engine is starting to burn oil after 100,000 miles. I take a mental note of these things, because I am still skeptical of lightweight synthetic oil being declared great! I do believe lightweight oil helps in the mpg department, & that is the driving force behind all this.

Sidenote: Subaru Foresters are highly recommended by Consumer Reports. Why is that? Some are burning almost as much oil as a 2 stroke engine.

There are more factors than lubrication that contribute to engine failures. Subaru has had oil consumption and engine failure problems for many years and apparently still hasn't overcome them. Until that's fixed, I won't buy one no matter how much Consumer Reports praises Subaru.

More info:

Blackstone Laboratories > Articles > Oil Viscosity

Blackstone Laboratories > Information > Newsletters > Why are Viscosities Going Down?

Motor Oil 101 – Chapter One – Operating Temperatures and Viscosity

I would encourage anyone to read the whole series whether or not they maintain their own vehicles. It is written in simple terms and can explain things better than I can, without a whole lot of rambling.

[stevedmc]

5w30 conventional every 5k miles seems to be working for me. Car has 230k miles and doesn’t leak or use oil.

[Eggman]

5w30 conventional every 5k miles seems to be working for me. Car has 230k miles and doesn’t leak or use oil.

And you use your Mirage very differently than I do.

You typically start your Mirage and drive long distances before shutting it off.

I typically start my Mirage and drive about five miles (8 km) to work each day and turn it off. During winter, my Mirage rarely reaches full operating temperature.

Internal combustion engines work best at full operating temperature. Your Mirage engine will last longer than mine simply because you use yours more at full operating temperature. No surprise.

[stevedmc]

And you use your Mirage very differently than I do.

You typically start your Mirage and drive long distances before shutting it off.

I typically start my Mirage and drive about five miles (8 km) to work each day and turn it off. During winter, my Mirage rarely reaches full operating temperature.

Internal combustion engines work best at full operating temperature. Your Mirage engine will last longer than mine simply because you use yours more at full operating temperature. No surprise.

My dealership uses 5w30 on all Mirages that come in for oil changes, including cars that only drive short distances.

[Mark]

There are more factors than lubrication that contribute to engine failures. Subaru has had oil consumption and engine failure problems for many years and apparently still hasn't overcome them. Until that's fixed, I won't buy one no matter how much Consumer Reports praises Subaru.

Subaru vehicles are very popular where I live, & they almost have a cult like following. Having said that, I don't see myself ever buying another one. The Mirage can't do everything I need a vehicle to do, however. I can't tow my compact tractor to my friend's place to put in food plots. I can't haul my UTV, ATV, or riding lawn mower around with a Mirage. I am not going to buy a ton of wood pellets and haul them home with my Mirage. When the winter roads are bad, my Mirage is not always going to get me home (& that happened last winter). It couldn't climb the ridge road that leads to my house (more of an ice issue than snow). For everything else, the Mirage serves me well. For 90% of my driving, I don't need an expensive SUV. Replacing an SUV is expensive. By owning/driving my Mirage, I am hoping to extend the life of my present SUV for many years. Having my Forester engine replaced this fall may help, too. I also have a daughter/son-in-law that live in Europe. When they visit the States, I let them use my Mirage. It's been perfect for that, too!

I bought my Mirage to be a daily driver. I wanted something that was cheap, reliable, and economical. The Mirage addresses those traits as well as any other vehicle on the market. Having said that, I would never pay more than $10,000 for one. If a vehicle doesn't come with a manual transmission, I am not really all that interested in it. Personal preference for me.

I purchased my 2011 Subaru Forester in 2013. It had 15,000 miles, & I paid $17,000. At the time, I was without a car because someone had rear ended my 2000 Honda CRV. I was driven into a pickup truck stopped ahead of me by a Chevy Tahoe. His Tahoe and my CRV were both a total loss. Neither one of us had comprehensive or collusion insurance. His liability insurance paid me $6000 for my loss.

In 2013 (& still today), your choices for AWD manual SUVs are very limited. Honda & Toyota had dropped their manuals years earlier. Subaru & Jeep were the two choices. If I could have found a low mileage 1st or 2nd generation Honda CRV, I would have considered that. Manuals are just harder to find overall. In 2019, Subaru has now dropped the manual transmission option in the Forester. Sidenote: When Subaru switched to CVT transmissions, the Forester's towing capacity dropped from 2,500 pounds to 1,500 pounds. That doesn't do anything to decrease my lack of faith in CVT transmissions.

I don't see myself buying another Subaru. I don't see myself owning a vehicle with a CVT transmission any time soon. Today's market is driven by mpg. I am not convinced that has made cars better in all cases. The market is also changing very rapidly. A lot of unproven stuff is put on the market. In hindsight, I would have held out & bought an older Honda CRV (AWD manual). Some people love their Subaru vehicles, & they continue to buy them year after year. I am not one of those people. At the same time, there isn't anything on the market that would make me want to trade in my Subaru Forester. I am not convinced the Jeep Renegade, Patriot, or Compass are better vehicles. If I didn't truly need AWD/4WD, I would consider an Outlander Sport (manual). Otherwise, there really isn't much out there that I like. Eventually, I may have to give up on manuals. In the meantime, I am hanging on to my Subaru. Racking up the miles on my Mirage helps me do that, too!

[Mark]

There are more factors than lubrication that contribute to engine failures. Subaru has had oil consumption and engine failure problems for many years and apparently still hasn't overcome them. Until that's fixed, I won't buy one no matter how much Consumer Reports praises Subaru.

More info:

Blackstone Laboratories > Articles > Oil Viscosity

Blackstone Laboratories > Information > Newsletters > Why are Viscosities Going Down?

Motor Oil 101 – Chapter One – Operating Temperatures and Viscosity

I would encourage anyone to read the whole series whether or not they maintain their own vehicles. It is written in simple terms and can explain things better than I can, without a whole lot of rambling.

I read all this, & it was a lot of rambling!!! I read Steve's post after this. One sentence, no rambling, 5W-30 oil, 230,000 miles, & no issues. I do note that Steve lives in the South, however. Where I live using 0W-20 during the winter months is probably a better choice (especially since it is the recommended oil). I haven't been using 5W-30 during the summer, but I surely wouldn't be against it. Different oils are recommended in other countries for this car. I doubt the 1.2 L engines are designed differently for each market.

Ford dealers use a synthetic blend (5W-30 or 5W-20 usually). You can buy Motorcraft oil at Walmart. It's very reasonable. Recommended oil changes are 10,000 miles for most new Ford vehicles. If I owned a Ford, I would change my oil @ 5,000 miles.

People are free to do whatever they want, & everyone should do whatever is best for them. If you lease a car for two years, who cares what a dealership does? If you want to drive/own a car for 10+ years, you may look at it differently, too.

[inuvik]

The two primary reasons I use 5w-30 is:
1: Reduction of the “sewing machine” noise of the valvetrain.
2: Viscovity of 0w-20 at 100C is very low

[Sprinter]

One forum member has well over 200,000 miles on his Mirage. It's approaching 250,000 miles. He receives free oil changes every 5,000 miles from the dealership, and it appears they may be using 5W-30 oil. His only problems have been A/C related.

This man
have 250k miles and use cheap synthetic 0w20 and change it every 6k miles