Fuel/Oil Dilution Issue Overblown ?

SDzx said:

Yesterday, I did another oil change and my oil smells of gasoline (again). Like many people, i bought the civic for reliability, its looks, and high mpg. This is my first purchase that went over $20,000 and honestly I'm a little pissed. Like many of you I worked hard for my money and expected reliability from this purchase. I'm not sure if the oil dilution problem is over blown. I've decided to get an oil analysis and make an informed decision from there.

One solution I did was add an oil drain plug with a valve for faster oil changes. I'm also planning on doing an oil change more often. I understand amsoil is a really good oil to use but also saw a video comparison of it compared to amazon basic were the results were "close." Amsoil still beat amazon basic in the comparison but amazon is cheaper. So I am hoping by changing the oil more frequently, my oil engine won't suffer too much wear from diluted oil. I was pretty religious on my old 350z with its oil change because the engine would just burn so much of it. I am thinking of continuing that practice with this vehicle if i decided to keep it. I do a lot of short trips and most of my driving is in the city.

I'm thinking of change it once every three to four months but to be honest thats just what i did with my Nissan. I think it is just trial and error and seeing what works for you. This was a lot longer than expected, guess I'm just ranting because my oil smelled of gas yesterday.

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Smell of gasoline in the oil is normal with GDI. That's because some fuel will get into oil guaranteed. If you want a car that has little or no gasoline smell in the oil, you need a car that burns oil. This means that the traffic around the piston rings is mostly in the opposite direction, so the fuel has less chance to get into oil. If the cylinder walls are covered with oil, the unburned gas will also not so easily condense on it. That's because the oil layer will be hotter than a naked cylinder wall. Btw. if you car burns oil, and you top it off, you don't need to change oil so often.

Why do you feel like you need your own oil test, when so many are already available? You suspect that your car is a unique case based on the intensity of the gasoline smell? How many is "a lot of short trips?" Do you allow the engine to completely cool down between these trips? Well, used oil from 1.5T will smell of gas, no way around it. What percentage fraction of oil dilution are you smelling? I mean did it smell more like 2% or like 7%?

What is missing in your post is what was the level of oil on the dipstick.

Gruber said:

Smell of gasoline in the oil is normal with GDI. That's because some fuel will get into oil guaranteed. If you want a car that has little or no gasoline smell in the oil, you need a car that burns oil. This means that the traffic around the piston rings is mostly in the opposite direction, so the fuel has less chance to get into oil. If the cylinder walls are covered with oil, the unburned gas will also not so easily condense on it. That's because the oil layer will be hotter than a naked cylinder wall. Btw. if you car burns oil, and you top it off, you don't need to change oil so often.

Why do you feel like you need your own oil test, when so many are already available? You suspect that your car is a unique case based on the intensity of the gasoline smell? How many is "a lot of short trips?" Do you allow the engine to completely cool down between these trips? Well, used oil from 1.5T will smell of gas, no way around it. What percentage fraction of oil dilution are you smelling? I mean did it smell more like 2% or like 7%?

What is missing in your post is what was the level of oil on the dipstick.

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I think his point is that the oil should not be smelling like Petrol at all. It should just smell like oil and not be diluted.

No one really knows how widespread this is or if every car will eventually suffer from it.

I got my oil tested not because I was worried about oil dilution, only because I was curious to see what I had in my oil. I run a E85 and Pump gas 91 blend (about 20-45% ethanol content), which should use more fuel theoretically since ethanol needs more to burn with the same amount of fuel. I use Amsoil Signature series with their oil filter and change roughly every 5,000miles. This was my second oil change. I do live in Los Angeles so I don’t experience freezing temps. But if for anyone wanting to see my results. Again I wasn’t surprised with the fuel numbers cause again I use ethanol and before I was driving a shorter compute to work 5miles one way, so I would let it idle on cold starts for about 5-10min 5 days a week for work. Also because this is a GDI so fuel gets dumped directly in and not all fuel always burns, so there’s bound to be some sort of mixture. Now I drive a little bit further for work (10miles) so will report with another result when it’s time for another oil change. Still let it idle for about 5min every work day though

darkness975 said:

I think his point is that the oil should not be smelling like Petrol at all. It should just smell like oil and not be diluted.

No one really knows how widespread this is or if every car will eventually suffer from it.

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Everynody knows. All GDI cars have some fuel in the oil. Mazda, Kia, Hyundai, VW... There is tons about it on the internet. And still new car owners discover it again every day. And some never do.

"Mazda GDI Fuel in Oil
Posted on March 25, 2019 by Information provided by Mitchell 1

This bulletin applies to 2014-2018 Mazda3 and Mazda6 vehicles equipped with GDI (gasoline direct injection). If the vehicle is driven on extremely short trips most of the time (where the engine never reaches normal operating temperature), the engine oil may become diluted with fuel, and engine oil level will increase.

Engine oil dilution with fuel occurring under these specific driving conditions is normal with GDI engines. If the vehicle is driven on a longer trip after “a lot” of short trips, the check engine light may turn on, with DT P0172:00 (fuel system too rich).

Newer GDI engines are designed so that high-pressurized fuel is injected directly into the combustion chamber, which may cause the fuel to adhere to the cylinder wall. The fuel is then scraped by the piston ring and flows down into the crankcase where it mixes with the engine oil.

If the vehicle is driven in a fully warmed-up engine condition with an increased engine oil level diluted with fuel, a larger than normal amount of fuel evaporates and burns off in the combustion chamber. This causes the air-fuel ratio to become rich. If the amount of fuel coming from the PCV system increases further and exceeds the air-fuel ratio correction system limit, the system turns on the check engine light and sets DTC P0172:00.

Customers who routinely make very short trips should be advised to have the engine oil and filter changed on a more frequent basis."

https://www.autoserviceprofessional.com/article/102542/mazda-gdi-fuel-in-oil

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4318691/5W20_Fuel_Dilution_GDI__-_Idea

I don't think its overblown. I have a 2017 Civic Touring I purchased with 21K miles. I am at 26.5K miles now and changed the car oil at 24K and after 2.5K miles, the oil went up by 2mm-3mm it seems. Oil level was right at the top hole on the dipstick and its definitely higher after 2500 miles. This car is driven 60-80 miles a day. Most trips are 20-30 miles long so the short-trip thing is not the reason for oil dilution. I live in VA and in the last month the car has been driven with the new oil our average temp has been on the warmer side for this time of year. I don't really know what to do at this point other than stick to changing the oil every 5000 miles or so.

2017touring said:

I don't think its overblown. I have a 2017 Civic Touring I purchased with 21K miles. I am at 26.5K miles now and changed the car oil at 24K and after 2.5K miles, the oil went up by 2mm-3mm it seems. Oil level was right at the top hole on the dipstick and its definitely higher after 2500 miles. This car is driven 60-80 miles a day. Most trips are 20-30 miles long so the short-trip thing is not the reason for oil dilution. I live in VA and in the last month the car has been driven with the new oil our average temp has been on the warmer side for this time of year. I don't really know what to do at this point other than stick to changing the oil every 5000 miles or so.

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I would send an oil sample for analysis, might have bad piston seals. Or how are you checking your oil, and how much oil are you filling up? Especially since I’ve seen a lot of people tend to over pour with these engines slightly above the upper oil marker because it’s not an even quart number. I have a little over 2k on my current oil and I drive short distances for work, but enough to get the oil warmed up and I have not had any rising oil levels. Has the vehicle received the ECU update from the dealer ?

jayy_swish said:

I would send an oil sample for analysis, might have bad piston seals. Or how are you checking your oil, and how much oil are you filling up? Especially since I’ve seen a lot of people tend to over pour with these engines slightly above the upper oil marker because it’s not an even quart number. I have a little over 2k on my current oil and I drive short distances for work, but enough to get the oil warmed up and I have not had any rising oil levels. Has the vehicle received the ECU update from the dealer ?

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I will get an oil analysis done with the next oil change (this one I have ran about 2 bottles of Redline SI-1 cleaner so dont want the results to be skewed). I filled up 3.7qts and when I did the oil change, I checked the oil while the car is parked at the same spot as it always is and the oil was right at the top hole on the plastic area of the stick. The first 1000 miles I did not notice any changes to the oil level, however, I checked the oil level this morning after the car parked overnight and it was a little bit above the top notch on the dipstick. I am not sure if the vehicle has received any ECU update. If this is something that would show up on Carfax, than it was definitely not done because when I picked up the car at the end of December 2019, the report showed no such thing. I will have to check with the dealer and ask this question directly as they may have more data in their system which was not reported to Carfax.

2017touring said:

I will get an oil analysis done with the next oil change (this one I have ran about 2 bottles of Redline SI-1 cleaner so dont want the results to be skewed). I filled up 3.7qts and when I did the oil change, I checked the oil while the car is parked at the same spot as it always is and the oil was right at the top hole on the plastic area of the stick. The first 1000 miles I did not notice any changes to the oil level, however, I checked the oil level this morning after the car parked overnight and it was a little bit above the top notch on the dipstick. I am not sure if the vehicle has received any ECU update. If this is something that would show up on Carfax, than it was definitely not done because when I picked up the car at the end of December 2019, the report showed no such thing. I will have to check with the dealer and ask this question directly as they may have more data in their system which was not reported to Carfax.

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Yeah I would take it to a dealer for the ECU update. I might not have as bad of a oil dilution because the 2019 models came from the factory with the update already installed. So I would definitely get that checked out at a dealer, and send in an oil sample as well and go from there see if the issue remains or not

Honestly this whole thing sounds like a really bad joke. We buy Hondas because of the long standing reputation of quality products.

The fact that this "oil dilution problem" is even a thing is beyond infuriating, especially for those like me that bought the car with longevity in mind and I am not interested in trying to "trade" it for a "newer" one, especially because that would entail having to start making car loan payments again.

I change the oil every 4K - 5K, not because of oil dilution fears, but because that is just standard operating procedure for me.

If I am going to have to be "afraid" of a possible engine failure at some point due to this oil dilution thing, what's the point in even having the car?

darkness975 said:

If I am going to have to be "afraid" of a possible engine failure at some point due to this oil dilution thing, what's the point in even having the car?

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I would agree there is no point to spend money to buy yourself another fear in addition to all the other scares in life. In this situation having a car may indeed be pointless or even harmful. Or, you can buy an old and tried non-DI car, if you can stoop so low. In my CR-V I change the oil about every 10,000 miles plus, and the oil in the crankcase never ever swelled during the OCI; to the contrary, it started to shrink a bit, like it always used to do in the good old times.

There is no need to live in fear. There are so many other wonderful cars to pick from, not even mentioning the 2.0L civics. There is no need to be married to the Honda 1.5T if it gives you anxiety. I recommend divorce.

darkness975 said:

If I am going to have to be "afraid" of a possible engine failure at some point due to this oil dilution thing, what's the point in even having the car?

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I'm agree with you! Even i'm not seeing any symptoms for my 2018 Civic HB sport. I bought this guy for reliability. I used to have 2007 scion Tc which has oil consumption problem! But i've never had problem with it, i was adding extra oil between oil changes. And for that issue if you watch oil level nothing gonna happen. I mean it won't harm the engine.
but this oil dilution issue, i'm not really sure! i feel like i'm really unlucky about cars!