Prius engine has an easy life

I appreciate you sharing that, the more data we can collect the better. Would it also be possible for you to scan and post the page from your owner manual/maintenance menu regarding the oil viscosity?

I was in Johannesburg SA around 10 years ago on business. There is a Toyota dealer - or was - called Zaal or Zwaal, something like that? I stopped in to take a gander at models not offered in North America.

I asked and apparently the only motor oil viscosity offered was 15W-40 and 20W-50. As you may be aware, there is a huge debate here on what sort of motor oil to use in the Prius. Some seem to think only a 5W-30 should be used, anything else the car will explode in fiery pieces

 

deleted

 

deleted

 

Take a look at the April 2008 Consumer Reports and compare MBZ quality as reported by its owners, vs. Toyota/Lexus quality reported by their owners. A big difference, and MBZ is not the winner. It seems that the electrical systems on German cars require lots of attention, which is not a good sign if/when the German manufacturers decide to step up to hybrid drivetrains.

 

Well, if you live in Canada it seems safe to use a 20 weight oil. However this might not be the best plan if you are driving through Death Valley at high speed in 120 degrees F ambient temps - unless TMS USA adds 5W-20 and/or 0W-20 to the approved list.

 

Of course, I've always believed in using a viscosity appropriate to ambient conditions. A lot of folks may not realize that the Military Arctic Oil spec MIL-L-46167 is a special 0W-20 intended for use in turbodiesels

That said, my used oil analysis running Mobil 1 0W-20 has always been good, better than Mobil 1 5W-30. The one time I tried Esso XD-3 15W-40 for the summer months, that also had very good used oil analysis results

Folks living in the EU, Australia, India, African countries, will use different viscosity. AFAIK a 0W-20/5W-20 is impossible to find outside of North America

 

A couple of nights ago, after my 45 mile freeway commute (at about 80°F - California winter), I had a quick dinner and changed the oil in my Prius. I figured it would still be hot enough to drain properly after about 1/2 hour sitting. The oil was only luke warm. I've been burned on the hot oil on other cars after a similar wait. It makes me wonder whether I'm wasting money on the Syn Mobil 1, with such a low demand, as far as heat, and engine wear seem to be. I've always used Mobil 1 in my cars since the 80's. But now I'm wondering if its worth the extra expense, considering the Prius engine has such an easy life. Is it possible go go back to dino after a life of syn? 55,000 miles. Just wondering.

 

Should be no problem. I change oil at 5K mile intervals, using 5W-30 Castrol GTX or Pennzoil (whatever I can get at Kragen's for ~$1/quart net of rebate, looking for their sale ads in Sunday LA Times) and use the Toyota-branded oil filter.

Given the 5K mile oil change interval, I believe synthetic oil, priced at 4-5x more, is not worth it. The Prius ICE is not like a high-performance Porsche or Corvette that is stressed to its design limits...

 

Yet the local dealer is still putting 'next oil change in 3,500 miles' stickers on the windows.

 

Actually, you want the oil hot enough to have the moisture and aromatics - if any - boil off. Otherwise, the first step to sludge is cool motor and cool oil

Given your location, you should be ok. In a bitterly cold climate, the cheap oil can allow sludge. Remember, the API/ILSAC have specifically ignored the following problems: ring land fill, crown land fill, cold black sludge, cold stuck rings, and cold gellation

 

Is anybody seeing an MPG boost from the 0W-20? How about leaving it a quart low? I'm still under warranty so I have to change it around 5K anyway so probably not...

As far as having an easy life goes, even when it's running, it can run at low RPMs even at freeway speeds while an AT or stick shift has to run at some multiple of the wheel RPM always.

 

Yes, you will probably see a small boost in mpg if you use 0-w20, as it is the motor oil of choice for Japanese hypermilers (which are probably the most hard-core owners).

 

Only in temps of -30 C and colder, and it's a minor difference compared to Mobil 1 0W-30

In summer, on the Trans Canada, no difference I could measure running 0W-30 or 15W-40. I like using either a 0W-30 or 0W-20 for quick oil flow when cold

 

finally I can add some technical content:

Standard motor oil is made through distillation. Basically they boil the crude oil in a tower and the lighter fractions are extracted towards the top and the heaver toward the bottom. A 5w-30 oil is a mixture of a variety of different lengths of carbon chains that average out to 5w-30. Since they all are of different length they average viscosity is not very linear with temperature, meaning the oil behaves differently at -30F than it does at 130F.

Synthetic oil is manufactured from natural gas stocks and has molecule chains of approximately the same size. This results in a much more linear viscosity across a temperature range. Synthetic oils have a much lower pour point, put a quart in your freezer next to standard oil and pour them out in the morning to prove it to yourself. Synthetics also break down far less than standard oil, does anyone remember the Mobil 1 ad where they have Mobil 1 and standard oil in frying pans and they turn up the stove all the way? Standard oil will sludge, synthetic will be just fine. Synthetic oil has a higher film strength meaning more of it will be stuck to the metal rather than drip back into the pan. The Wikipedia entry would drive my Chem E professors crazy but is generally OK:
Synthetic oil - Wikipedia, the free encyclopedia

Synthetic oil should not be used in the initial break in period of 1-3K miles because the reduced friction interferes with the break in process.

Yes synthetics don't break down but they still accumulate the combustion byproducts and acids and needs to be changed regularly. I gave up changing my oil and pay Jiffy Lube $60 for a Mobil 1 change every 4-5K miles or every 3-4 months. I'll run the 5-w30 spring, summer and fall and will switch out to 0w-30 during winter and hopefully avoid needing a block heater.

I have always been amazed how people spend $25K on a car and cheap out over $250 in motor oil in what is arguably the most important maintenance task.

Use synthetic oil once the car is broken in, it's the best investment you will make in your car.

my car history:
1984 Nissan Sentra $175K miles, sold for $300
1990 Ford Taurus $180K miles, totaled when a drunk head on hit me
1998 Ford Escort wagon, $156K miles running strong, I just got sick of it
2008 Prius, hopefully 150K plus miles!

 

Good points. I have a few things to add

The Prius operated in the EU market has a normal 12 month or 10,000 mile OCI. The viscosity range is different too. An owner from Spain was nice enough to scan his owner handbook, I've attached a thumbnail

In the EU, there are quite a few cars, especially GM mainstream cars and VW, with normal 24 month or 30,000 mile oil changes. They run synthetic right from the factory

Mobil 1 0W-40 is rated ACEA A3, B3/B4 and meets the requirements of Mercedes, BMW, Porsche, etc. The typical oil change interval for this oil is 18 months or 18,000 miles

I've run Mobil 1 0W-20 year round, and the used oil analysis after 16,000 km was fine. So clearly this car is good for extended oil changes with proper oil and monitoring

The only concern I have is using Jiffy Lube. Some forum members have had very bad experiences, including engine damage, from the use of those quick lube places.

Make sure they understand the Prius power up and power down correctly. Otherwise if they just press Park, and the motor is off, they may think the car is powered down. They'll have it up on the lift, oil drained, and the motor could restart.

As far as synthetics, I first started using them 25 years ago due to their proven cold weather performance. Conventional oils make use of polymeric additives that function as "pour point depressants." Once the oil has some use, those pour point depressants can be used up and you will experience gelling

A good way to determine if an oil has a lot of pour point depressant additive is to compare the tested pour point to the tested borderline pumping temperature. If the BPT is rated COLDER than the pour point, stay away, the oil has heavy pour point depressant additive treatment

 

Thanks for the tip on jiffy lube, I will make sure they know what they are doing. I've been to shops where they can't drive a stick.

Synthetic is the only way to go.