Mobil 1 1.9k miles / 2020 48k miles Rav4 - Fuel Dilution

[SC Maintenance]

I have the ICE version of this car. The engines are the same mechanically - dynamic force (port and DI). They do have a fairly different tune by application obviously - hybrid has more miller cycle.

I have not heard of this engine having dilution problems. Its been around since the 2018 Camry, so I would think you should have heard of it.

I would pull long term fuel trims via OBD and see what they look like. Maybe start doing longer drive once a week and see if it improves at all.

How has the gas mileage been - calculated not the trip computer?

Unfortunately my experience with Toyota dealers is the same as every other dealer - nearly worthless unless it glaringly obvious - like a no start or something.

 

[fueldelusion]

Car says low 30s during winter and high 30s during summer. Hand calculations have always showed 2-4 mpg less than the cpu.

Didn’t even notice the soot in the report. If it was at diesel levels, wouldn’t it be jet black? Oil on the way out was as clear as the day it went in.

 

[Pablo]

Car says low 30s during winter and high 30s during summer. Hand calculations have always showed 2-4 mpg less than the cpu.

Didn’t even notice the soot in the report. If it was at diesel levels, wouldn’t it be jet black? Oil on the way out was as clear as the day it went in.

All this is for the lab to answer. We can give some opinions, but they should be able to explain.

 

[fueldelusion]

All this is for the lab to answer. We can give some opinions, but they should be able to explain.

Reached out to the lab, they only hold the sample for 30 days.

 

[Pablo]

Reached out to the lab, they only hold the sample for 30 days.

Well that parts sucks, but they had no explanations?

 

[fueldelusion]

They wrote a nice reply:

“Samples are retained for 30 days. Unfortunately, we would not be able to have the sample retested at this point. However, you would be correct in that Zinc and Phosphorus are too high for what’s allowed to meet API SP requirements. These levels are limited to about 800-850ppm. There is no limit for Calcium though. As far as the soot, at high enough levels, soot can certainly turn oil black. This is normally why diesel oils turn black after little usage as they tend to generate a lot more soot than gasoline engines. At 1% and this being a gas engine, I wouldn’t expect the same type of appearance compared to what you’d see with a diesel oil sample. For fuel dilution, ASTM D7593, which is the standard method for fuel dilution testing by GC, fuel is measured up to 5% for gas engines; 10% for diesel. In regard to the wear, at 22ppm it would not be considered abnormal or high at that mileage. It would be best to pull another sample at either the same mileage or double that mileage to see if the amount trends the same. Being it’s only one sample, we don’t know if that is the normal rate of wear for your engine or if this was just a one time result. The method of taking the sample can affect wear metal levels as well. If the sample was taken from the drain plug, it’s possible that any sediment at the bottom of the pan got into the sample, skewing the results.”

Overall I’m not super concerned with anything, especially after some other Toyota Hybrid guys chimed in (thank you). I’ll UOA this 5W-30 and make decisions from there. Only so much a $40 UOA can do.

 

[We're Metals]

My 2020 Rav4 Hybrid has never had a fuel smell in the oil in the 76,000 miles I have owned it since new and done all but 1 oil changes with 0w-20.

 

[Titan]

M1 0W-40 is now SP so it’s calcium levels are safe for the DI so I’ve considered that.

Not sure where you are getting the idea that Direct Injection engines have a calcium limit. Are you referring to tendency of high calcium contributing to Low Speed Premature Ignition? LSPI can be a problem in some small displacement Turbocharged engines that also have DI. That's not your engine...calcium level isn't important in your case.

 

[fueldelusion]

My 2020 Rav4 Hybrid has never had a fuel smell in the oil in the 76,000 miles I have owned it since new and done all but 1 oil changes with 0w-20.

I wonder if our driving conditions differ. Of the 2k miles on the oil, i bet around 25 percent have been while the oil was at full operating temp. I had not noticed any signs of fuel in the summer where we do much longer trips and it doesn’t frequently have to start at 0 degrees or less.

Not sure where you are getting the idea that Direct Injection engines have a calcium limit. Are you referring to tendency of high calcium contributing to Low Speed Premature Ignition? LSPI can be a problem in some small displacement Turbocharged engines that also have DI. That's not your engine...calcium level isn't important in your case.

You’re probably right and I have had the same thoughts. I have read in enough places that high calcium and its relationship with LSPI applies to direct injection engines that aren’t necessarily turbocharged or low displacement. It was enough for me to avoid older, non SP M1 0W-40 when I decided to try something thicker than 0W-16.

 

[We're Metals]

I wonder if our driving conditions differ. Of the 2k miles on the oil, i bet around 25 percent have been while the oil was at full operating temp. I had not noticed any signs of fuel in the summer where we do much longer trips and it doesn’t frequently have to start at 0 degrees or less.

Very different, I have a lot of highway miles.

 

[Marcozi]

OP, take the car on a 30 mile+ trip at highway+ speeds on a weekly bias. That will boil off all of the fuel dilution.

 

[kschachn]

OP, take the car on a 30 mile+ trip at highway+ speeds on a weekly bias. That will boil off all of the fuel dilution.

Not necessarily at all. It also depends on how and when the fuel is getting into the oil.