Would you use 5W40 for your Prius C?

The OP's not 100% clear, but I believe he said he offered to supply them with the 0W20, in his opening post.

 

Right, I missed it. However, if dealer offers free oil changes with 5W40 that is acceptable in that hot climate, why not?

 

Anas, I live in Aqaba and temperature average at summer time is 35-45 C, so you recommend to follow the dealer advice and use th 5w 30 ? noting that my 2013 is freshly coming from USA and the oil in engine is 0w 2o

 

Using a slightly higher weight will not harm ANYTHING.....except maybe your gas mileage a tiny bit.
In a REALLY HOT climate, the 0W20 probably isn't the best choice.
I believe that the owners manual even allows a bit of latitude.

 

A lot in hot places, actually. Singapore allows for 50w.

The rest of the world isn't North America, nor are they enamored with 20w.

 

the point here, if i use the 0w 20 in the hot places like my city (35-45C) what is the harm?

 

95-113 f, probably none. Not unlike temps in the American south where 20w is standard to use in vehicles that call for it. Modern cars, modern oils, reasonable oil change intervals, good results.

If you are not a slave to the mpg, at those temps 30w would be entirely reasonable.

 

I guess my question would be is there harm? Should you switch to 5W or even 20W during the hot summer months? Do Prius owners in Florida use OW ?

 

The thing I have noticed most about "oil discussions" on priuschat is that US owners push the limit. Longer change intervals, lightest oil for best MPG, not driving with the flow...then preach to others about saving the world. The OP will be just fine with the way they do it there, "especially" after the early first change. If you use quality spec oil/filter within the weights given catered to your environment/service duty cycle, "monitor the level" and change it at 5,000 miles you will be fine. Ever wounder why so many other countries recommend oil changes at 8,000 km (5,000 mile)? The heavier weight oils listed in the owners manual will not hurt your Prius.

 

Strictly speaking, no.......because the 0W20 is a 20 weight that doesn't thicken up in cold temperatures.

But yes, the dealers here use the recommended 0W20.......or claim to.
And I can't speak for ALL of them, obviously.

 

By and large, 20w is 20w at operating temp regardless of whether 5w or 0w. Engines operate well at multiple oil weghts. Could I guarantee zero damage with either 20w? No. . No more than I could do so with any other weight. Too many variables, but your temps are not so special.

0w-20, 5w-20, 0w-30, or 5w-30...you could use any of them with no problem. Which is best can not really be answered as there are so many variables and scenarios that greatly overlap. Choose your oil and live with it. You would likely do as well as anyone.

 

I have been using Lexus 5W40 fully synthetic oil from the dealership and felt a little sluggish response on the car when i first had its oil changed but now after 1000 km i am getting around 47 mpgs average and no problems with the car so far.

I'll be using 0w20 in the next oil change and document the difference

 

It depends on the oil's additive package. Once at operating temperature, there are 0W20 oils that flow thicker than some 10W30's.

This link is from Mobile 1, and tells you that their 0W40 (BMW LL01 cert) flows better at cold temps than their 10W30, but is thicker at operating temps. Mobil 1 0W-40 or Mobil 1 10W-30 in Newer BMWs

Look up some articles written by Kevin McCartney. You probably can't check the archives on the International Automotive Technicians Network without being a member, but there's a huge amount of info on modern oil spec in there, and the problems seen in the real world when people don't follow the manufacturers specs for oil. Long gone are the days of "I like Mobile 1." Many engines have an oil certification that has to be met (not just generic ILSAC or API). The phrase "Meets or Exceeds" is word play, and does not mean that an oil is "approved or certified." For instance, BMW's require a BMW LL01 certification that's carried by Mobile-1 0W40 and Valvoline SynPower SAE 5W-30, but not Mobile-1 5W30. Consensus on the Internet is that it's a scam designed to get you to go to the dealer, but on the maintenance side of the industry, we're seeing engine failures because of this, and manufacturers not warrantying the repair.

Keep in mind that Magnuson-Moss only applies when the manufacturer tells you that you must use their product. Not a product with their certification. We've already seen lawsuits on this, and the manufacturer wins every time.

Oil in modern cars is a very complicated issue right now, with many repair facilities not knowing what to do, because they can't stock 20 different oils, and one size doesn't fit all anymore.

Toyota 0W20 is a synthetic oil that covers all operating temperatures, and is good anywhere in the world. EVERY TOYOTA sold in Japan, with the exception of turbocharged and diesel, uses 0W20. Every one has one change interval: 1 year or 15,000 km. Japan has one of the most severe drive cycles in the industrialized world: Stop-and-go short trips.

Toyota's 0W20 is also formulated to combat sludge, which has the potential to be a problem in hybrids due to the short-trip nature of the car. The benefits of running 0W20 go way beyond gas mileage.

I took the easy route. If it's a Toyota calling for 0W20, we put 0W20 in it, and it comes out of a can that says Toyota on the side. Ditto Nissan, Honda, etc. If you can't get the manufacturer oil, you better make sure it meets the manufacturer's certification requirements. In the case of the Prius C, it's as simple as API SN/ILSAC GF-5. Keep in mind that 0W20 is almost always synthetic, and the 5W20 may not be. If you do go with a thicker oil like 10W40, and it's operating viscosity is thicker, there are other drawbacks than just mileage; say the 0W20 is synthetic (as almost all are) and has a higher shear rating (less wear), and circulates quicker on start up (less wear).

The real reason Toyota wants you running 0W20 in the crank case is because that's what they designed the engine to run with, and that's what it performs best with.

Cheers.

 

Oil weights are classified in ranges. If an oil viscosity (at 40*c or 100*c) falls within the range of 20w oils, it's a 20w. Viscosity index modifiers allow it to flow in a different range at cold temps, yet flow like a different weight oil at temps. But it will be a 20w or 30w or 40w oil as advertised. Viscosity modifiers may shear and take an oil into a lighter weight range, or the oil may thicken into a higher weight range, but a 20w is a 20w if it operates in the 20w viscosity range. If it doesn't, it isn't.

Oils may be designed to provide operating parameters that meet certain manufacturer's criteria. In certain applications this may be very important. In other applications, not so much. Generally speaking, it is desireable to use the thickest oil necessary, but the thinnest oil possible. Most engines can operate with a variety of oil weights, depending on the local temps. CAN being the operative word. There are places in the world where the local distribution system may not carry but one or two oils, and you take them and say thank you. Local temps may indicate thicker oil may be desirable. The Toyota Mothership itself gives different weight oils the green light in different locales.

I don't buy cars that need magic oils, or super-specific requirements. I buy normal cars that use normal oils that can be found in normal stores. My local temps are normal. Yet my car can operate on just about any weight oil that is reasonable. Even alphabet soup certified mechanics spew herp and derp about oil, and any number of issues that may contain opinions. A person can't really trust anything that comes out of a manufacturer's mouth due to advertising, lawyers, sales requirements, local customs, traditions, and basic human variability. You would have to be actually INSIDE the room with the group of engineers that developed the oil requirements for an engine or engine group to know what weight of oil is precisely what the engine was designed to use and under what circumstances. Anything outside that door is suspect from the word go. You can be pretty sure of your vehicle requirements if there's a specific and narrow certification, but lacking that there is a wide variability. You can use what is reasonable.

It's the "what's reasonable" that makes the world so interesting. Of course, everyone has their opinion.

 

Another interesting thing is that increased oil consumption is a commonly noted "problem" when using the higher viscosity oils in engines designed for thin oils. All of these engines now use "low tension" piston rings. They are designed to "scrape" the oil off of the cylinder wall as they descend, and then seal as they move upward. Thicker oils at operating temps have a tendency to leave more behind, as they don't come off of the cylinder wall as easy. We've seen engines burning up to a quart per 2,000 km (which is acceptable by manufacturer standards). Going to a thinner oil fixed the problem.

Of course, all of the grades listed in the owners manual are "safe" for this engine. Just noting some of the effects the different ones have. It's not just about saving gas. Almost all Toyota engines will run fine with almost anything you put in them.

 

"We've seen engines burning up to a quart per 2,000 km (which is acceptable by manufacturer standards). Going to a thinner oil fixed the problem."

BS. "Assuming" authorized spec oil was being used and no other mechanical defects existed, stating that said burn rate was fixed "solely" buy going to thinner oil is simply untrue.

 

One important thing that is seem to be missed in this discussion is that engine runs at its operating temperature, determined by thermostat and cooling system settings, not at the ambient temperature. Whether I drive at 0C ambient or 35C the engine ( and Oil) temperature is the same, after short initial warm-up of coarse. You can check this with Scangauge. If your engine is getting hotter when its hot outside, there is something wrong with your cooling system.
- Alex

 

When I go to the dealer I insist on Amsoil!