Synthetic Oil

8) Once your ICE has broken in approx. 5,000 to 7,500 miles you will see an increase in gas mileage. If the weather is cold your gas mileage will drop even if you use synthec oil.

Ben

 

John1701a uses synthetic and believes it gives him a slight mileage advantage. He keeps detailed records, so has some concrete basis for his assertion. However, I have never seen any independent studies one way or the other. I'd go with synthetic just for the bragging rights if I believed I'd get better mileage, but I want more than one person's numbers, even if that person is as meticulous in his record-keeping as John.

There's another issue with synthetic, which arises only if you expect to trade in or sell your car: Some people believe (and Toyota explicitly states) that if you switch to synthetic, you should never switch back. Whether this is true or not, many people believe it, and therefore a person who does not want to spend the extra money on oil might be reluctant to buy a car that has been using synthetic. This could be a problem at re-sale or trade-in time.

It's clear that the Prius, with its small, cool-running, low-torque engine and low-stress starting procedure does not require synthetic oil.

 

There's not a whole lot to add to that. (Thanks Daniel.)

My only comment to add is since I change my own oil, the total cost (including filter & gasket) is only $23.77

With a price so low, why bother using dino oil?

 

As far as the argument for improvement in fuel economy, that could be statistical "noise" and not real. That said, there are some situations where synlubes make sense:

1. Extreme cold temps -30 C / -22 F or colder. Most conventional 5W-30 oils turn solid at or slightly below that temp, and they only have to be "good" down to that temp.

2. Extreme hot temps, say +40 C, combined with heavy loads or high speeds. A synlube is much more resistant to breaking down and forming deposits.

3. Extending oil change interval, as the synlube is more stable. The motor stays cleaner.

I personally use synlubes for the much improved cold weather performance.

When I first bought my house in the 'burbs, I had to finish the basement. I used the attached garage as the workshop and parked my 2000 GMC Sierra outside. I had synlubes in the axles (Mobil 1 Gear Lube), transmission (Mobil 1 ATF), and motor (Mobil 1 0W-30). It was January before I finished the basement.

At -38 C, with a brutal windchill, even if you plug in, you need luck starting. My truck would always instantly start, without any noises. The neighbor kept his car parked outside (Garage packed up to the rafters with junk) and most mornings his car barely turned over.

When it did finally start, it would knock like an old diesel. I casually mentioned that he could use an oil that would make all that go away, but he thought it "cost too much." Then his starter went ...

Even though I now live in a condo with heated underground parking, I still prefer to use synlubes. Out there on the streets, it's still -35 C. To me, it's a comfort issue, as I feel safer with the extra protection.

I suppose if I lived in a "moderate" climate I probably wouldn't bother with synlubes. In this climate, there is no way I'd run anything else.

 

My '89 Civic was always parked outside. I did plug it in, but there were times when it sat, unplugged, all day long, at bitterly cold temperatures (maybe 20 below F). It always started fine, with regular oil, though it cranked slowly. I attribute this to the cold battery.

I'm going to talk to the folks at the dealership. Since I'll probably trade in my Prius when the next major model revision comes out, I'll ask them whether the use of synthetic would affect the trade-in value. (Higher because it's better for the car, lower because it imposes the requirement to use synthetic on the next owner, or none at all because they don't know or care about the difference.)

 

People claim this alot. It is true, that synlube is stable for longer periods, the problem is with contamination. CR did an extensive study on oil stability using NYC taxi cabs, and found oil should not be left in an engine more than 6000 miles due to contamination. Therefore, I don't think they recommend synlube under normal circumstances, since dinolube held up enough.

Now with a Prius, the engine runtime is less per mile, so there is less contamination per mile, so it may be feasable to go beyond 6K miles, though your warranty requires oil changes at 5K.

If 6K was good enought for taxis with dinolube, then 3K is more often than neccessary, no matter what mechanics may say, especially on a prius, though it won't hurt.

 

Dan:

Perhaps the biggest critique of the CR Taxi test is the fact the taxi's rarely experienced cold starts. Like most taxi fleets, they are started once or twice a day and stay running the entire time.

As far as extending oil drains, to a certain point you have little to fear using either dino or synlube oils. All other things being equal, the synlubes are more stable.

The biggest drawback to extending oil change intervals is the primary oil filter will barely filter down to 25 microns. To be really effective, you need to filter down to 1-5 microns. That requires the expense of a bypass oil filter setup.

To be really safe when extending oil change intervals, you also must perform UOA (Used Oil Analysis), which isn't free. If you have a HD truck that holds +20 litres in the crank, then it makes perfect sense to perform UOA and only change the oil when you really have to.

The primary reason I use synlubes is the proven performance in extreme cold temps, especially below -30 C. Most conventional 5W-30 oils experience gelation at -25 C, and turn solid at -33 C. At -40 you have a substance resembling thick taffy, with the same flow properties.

A good synthetic 0W-30 is good <-50 C. Around 16 years ago I had a contract job at a paper mill commissioning a new process control system. I was driving my old (Not so old back then) Ford F-150, running Esso XD-3 0W-30 in winter. Even at -42, it cranked briskly and fired, with almost instant oil pressure.

If I didn't have to worry about a climate that can dip to -40 (-42 forecast tomorrow night!), I would probably run a good regular 5W-30 year round.

 

That's my point. It is not a good idea to rely on Synlube's longer life to extend oil changes, because of the contamination, as CR found, even for taxi's. Cold starts would make the situation worse.

Unless you needed the better stability of synlube other than extending service intervals, dinolube would do just as well. The weight determines its state at specific temperatures, so comparing 5w-30 to 0w-30 is not fair. However, I get the impression there is no such thing as 0w-30 in dinolube, in which case synlube would be a good option in your case during winter.

 

Dan:

Right. I first started using synlubes for the reliable extreme cold temp performance. As I mentioned, unless you have an exotic oil filtration system, you can't go beyond the recommended OCI. In severe short trip and cold temps, you had better divide the time/distance recommendation by 2. Or maybe by 3 to be safe.

You can readily compare low temp flow properties using the ASTM D4684 MRV (Mini Rotary Viscometer), which specifies what the maximum flow viscosity can be. Comparing regular 5W-30 to synlube 5W-30, the low temp properties are readily apparent.

A typical regular 5W-30 will experience gelation (Begin to freeze) at around -18 F and will no longer be suitable below -22 F. A good synlube 5W-30, such as Mobil 1 5W-30, is resistant to gelation and is good to about -52 F.

As far as I know, you can't refine a 0W anything from conventional basestocks. As a rule, all 0W-xx are synlubes, such as 0W-20, 0W-30, and 0W-40. Mobil 1 0W-30 is good to about -62 F.

One might argue that if the temp never drops below, say, -35 F, they should only use an oil "good" to that temp. That's also false. There are very noticeable differences in flow properties as you encounter colder temps.

All other things being equal, a synlube 0W-30 will flow much faster than a synlube 5W-30 at the same cold temp. And a synlube 0W-20 will flow faster than a synlube 0W-30.

If you intend to keep a vehicle a very long time, the extra "cost" in running a synlube pays off in much better cold temp performance. At least you can depend on the thing at -40.

While doing that contract over winter at the paper mill, I was constantly amazed how folks raised in a frigid climate couldn't seem to figure that one out. One day the power feed to every plug-in in the parking lot got severed by a backhoe.

My Ford F-150 briskly cranked and almost instantly fired, though it did take forever to warm up at -40. Everybody else needed a boost as their starters barely turned over at all.

I wish I lived in your climate. I wouldn't have to worry about it.

 

My Dad bought into that story, and started changing the oil on his cars every 5k miles. For his car, this was OK, as he is a high mileage driver with a mostly highway commute. On my Mothers car, this ended up proving to be a disaster. I bought her 88.5 Suzuki Samurai, and found the engine HEAVILY contaminated with sludge. Once I got that stuff out of the engine, it was burning oil at the rate of a quart every 250 miles by the time it hit 80K miles. From my experience, that CR article wasn't worth the ink and paper used to print it.

As for my Prius, I am using synthetic oil, and did get a slight bump in mileage (about 2 mpg.) Since I have an '03, I'm following the 7500 mile service interval for the car since I drive 100 miles per day, over 85% of which is highway. The oil is cleaner at 7500 miles than what the dinojuice used to be at 3,000 miles. It is my plan to see how close to 300k I can get this car, if not beyond that number, if the car is still proving to be up to the task by then.

Many people bite into another misconception with synthetics. Do NOT believe the hype, that the oil can be left in longer than the manufacturers recommendations for service. Just like dinojuice, it picks up blowby and wear metals from the engine, and carries it around in suspension.

Synthetic oils are superior, so long as they are used correctly. I highly recommend using Mobil 1 in the Prius. However, keep to their service schedule. You should see a slight mileage bump, and much less wear in that first startup, when conventional oil is thick, and slow to get circulating.

 

But here in Europe our warranty requires oil changes at 9321 miles (15k km !) for the Prius. I had 3.7 liter Shell Helix (10W40).

I think that the quality of the oil-filter also has to do with it.

 

Exactly. What CR didn't address was the severe moisture contamination resulting from short trip operation. Their infamous NYC taxi fleet was rarely shut off.

The typical short trip driver will make frequent starts/stops, loading the oil with moisture and unburned fuel. Regular oils turn to sludge when exposed to moisture and fuel. Synlubes are much more resistant to that sort of breakdown.

You can run a motor to the maximum recommended "normal" OCI on synlube even when operating under "severe" conditions, and not have problems. My 1984 Ford F-150 has +500,000km with oil changes every 6 months or 10,000km. I had the valvecovers off several years ago to check the rocker arms and the motor is spotless inside.

In that Ford motor I used Mobil Delvac 1 5W-40, Esso XD-3 0W-30, Mobil 1 15W-50, Mobil 1 0W-30, and now Mobil 1 0W-20. I matched the viscosity to expected temperature, always running the 0W-30 and now the 0W-20 in winter, the heavier viscosity in summer.

My first reason for using synlubes up here is the dramatically improved low temp pumpability, especially -35 or colder. Everything else is an added benefit.

 

It's very interesting that only in North America are these water-thin motor oils recommended. Maybe a 5W-30 or 5W-20 is best for short trip, low speed operation. Certainly for extreme cold, the lighter the better.

Contrast that to the much higher autoroute speeds flat out in Europe, and I think you would have engine wear and failures running any xW-30. Much like how Toyota in Australia recommends a 20W-50 in their cars and trucks with gasoline motors, and a 15W-40 for their diesels.

Shell Helix Petrol is a very high quality motor oil, with much higher detergent treat levels than here in North America. Remember that European ACEA oil performance guidelines require their certified motor oils to be less than 15% volatile, with in-use thickening less than 50%.

Here in North America, SAE and ASTM allow a motor oil to be 25% volatile, and it can thicken up to 500% in use. Scary numbers.

 

Only if you use the proper <5 micron absolute bypass filter in conjunction with the primary full-flow oil filter.

Otherwise you must change at the manufacturer recommended interval. The primary filter is incapable of <25 micron filtration.

 

Is this another example of a product dumbed down for the American market?

Toytota engineer: "We better not have the Stealth button in the American Prius model because they would not know how to properly use it . . . and we better make them change their oil every 5,000 miles, because we know they forget to do it half the time." :wink:

 

Actually, the 5k interval stems from the number of V6 engines Toyota ate when they were trying to extend the drain intervals on their cars.

 

The best argument I have seen for using synthetics is to reduce dependence on Foreign oil. At this point I am ready to do every little bit to reduce oil imports. It may be small but it is a thing that I can do. If I get a 1 mpg increase I have helped again. Enough is Enough and we have gone beyond that.

 

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Is this another example of a product dumbed down for the American market?
:wink:[/b][/quote]

Sad but true.

Though I would have worded that as "North American market." Plenty of Canadians are just as guilty of it.

 

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I think you would "gain" more wrt reducing foreign oil dependance by extending the oil change interval.

Consider our European friends have OCI that appear to be 2x our OCI. With quality synthetic oils, that's easy to do.

Remember that in Europe the ACEA sets the standards for motor oil, and they are made up of engine makers. Their standards are very strict, such as max 15% volatility and max 50% viscosity increase in service.

Our ASTM and SAE motor oil standards are set by the oil companies. Among other things, a motor oil sold here can be +25% volatile, and the in-service viscosity increase can be +250%. They used to allow +500%!

So we're not even comparing apples to apples. No wonder Toyota had a problem with all those 3.0 V6 "sludge monsters" if they expected longer drains from no-name $0.79/quart mystery oil.