Is 10w30 oil really ok?

Yeah I can understand how frustrating this must be. It's like the old saying goes, if you want something done properly you've got to do it yourself. Annoying though that this should be true.

Personally I don't think 1/4" over is going to hurt anything. Though some people here disagree with me on that point.

 

A piece of brand new aquarium tubing from a retail store will run you $2 to $4. 30 seconds to shove it in the dipstick hole and suck up a bit, then walk away for an hour. Problem solved. Just never use it for fish!

 

My explanation is that:

1) you need to be parked on a totally level surface when doing the check and
2) depending upon how long the engine was off before the oil level was checked at your mechanic's shop, some oil may still be dripping down from the valvetrain area into the crankcase.

The oil volume is not going to contract a significant amount due to colder weather.

If your car was parked at a level area at your mechanic's shop, then I think you should accept his dipstick measurement and consider this particular project complete.

 

I would say it is inadvisable:

1. When living in south Orange County, I tried using Toyota 0W-20 full synthetic on the 2004 and noticed oil consumption from that point forward. Even after moving back to 5W-30 full synthetic, the oil consumption continued. The rate currently is 1 quart per 5K miles, 170K miles on odometer.

2. TMS USA has specified 5W-30 for Classic and 2G Prius. 0W-20 is allowed by other Toyota sales divisions, for example in Japan and Europe. However the US desert southwest can get quite hot in the summer, and if you drive in that area (for example, to Las Vegas, Death Valley, or Phoenix) then you may need the thicker oil viscosity provided by 5W-30.

3. You might see a 2-5% mpg improvement by using 0W-20, so its up to you to compare the potential mpg benefit vs. the potential downside of increased oil consumption.

 

I agree with Patrick......but had to go back and look to see how old your car IS; I assume the mileage is fairly high.

If it was a near new vehicle, the situation would be entirely different.

AND if you have been experiencing increased oil usage in a high mileage engine, it might be beneficial to try a "high mileage" oil; that is one for high mileage cars, not one that allows a lot of miles between changes.

 

Stick with what had worked, 5w30. I use Toyota own brand 5w30 as I get it for Toyota cost price, otherwise I'd use a decent brand like Mobil 1, Castrol etc

 

Stick with what had worked, 5w30. I use Toyota own brand 5w30 as I get it for Toyota cost price, otherwise I'd use a decent brand like Mobil 1, Castrol etc

 

I suppose it could be coincidence, but I tried 0w20 once in our Prius at about 130K miles. 1000 miles later I was a quart low. Had never burned a drop of oil before. Oil level was always at the same level coming out as going in before that.

Switched back to 5w30 but the oil consumption continue although at a much lower pace being a quart down after 5K miles. Still prior this, our engine had never consumed oil.

We're now running 10w30 and the oil consumption is about 1/2 quart every 5K miles.

With a 5w30 oil, as an example, the oil is a 5 weight oil. They add viscosity modifiers to thicken the oil as it heats up so that by the time it is up to operating temperature a 5w30 oil is like a 30 weight oil at operating temperature. The problem is, the thinner oil doesn't protect as well. It's a tradeoff between better cold start fuel economy and engine protection.

All things equal weather and climate wise, if I were choosing between 5w30 and 10w30, I'd choose the former for frequent short trips and the latter for frequent long freeway trips. Our car commutes about 100 miles a day on the freeway, so we use 10w30.

BTW, with 0w20, we noticed a considerable drop in fuel economy.

 

"BTW, with 0w20, we noticed a considerable drop in fuel economy."
Do you mean that fuel consumption declined; or do you mean that the mpg declined? I would be surprised to hear that the mpg declined with the thinner oil in service.

 

Yeah I'm kinda interested too if that was a typo and you really meant fuel consumption.

FWIW I'm in the 5w30 camp as well. I have to admit that 0w20 is expensive and a bit hard to find around here, so that's the main reason I haven't tried it. Anyway, I get amazingly good fuel economy (55 to 60 MPG) with 5w30 and still have fairly low oil consumption at 210000 km. So for me staying with 5W30 is mostly just a case of: "if it aint broke, don't fix it".

 

In Australia, is your unit of measure the Imperial gallon? Would like to know whether the US audience should divide your mpg results by 1.2 or not...

 

Hi Patrick. We use liters as our volume unit and L/100k (liters per 100 km) is our most commonly used measurement of consumption. I just convert these to MPG-US when I post here, because I know that's what most members here are familiar with. I actually get about 4.0 L/100 km.

My full tank (reported) consumption is nearly always in a fairly narrow range from 3.9L/100k (60 MPG) to 4.3L/100k (55 MPG).

BTW. We used to use miles and gallons (UK) here, but that was quite a long time ago.

 

I mean my fuel economy dropped as in I was getting fewer miles per gallon with temperature, tire pressure, and other factors including driving patterns not changing.