I have two new Mazdas with direct injection. Based on what I have read here (and excuse by non-technical explanation), direct injection can dilute motor oil which can also reduce the oils viscosity, sometimes below what is recommended by the vehicles manufacturer. In numerous cases, members have suggested increasing an oils weight to address this issue (ie going from 0w-20 to 5w-30). But, I'm also aware there are thick and thin varieties of each weight mentioned. Mazda recommends 0w-20 for both of my vehicles. I'm in my mid 70's and it's a pretty good chance these will be my keepers for the future so I'm looking to keep them in the best of health assuming this to be true. Would I be better off sticking with 0w-20, albeit a thicker one, or bumping up to a thinner 5w-30? I will be using a 5000 mile oil changes interval on both cars and currently using QS 0w-20 Full Synthetic. I believe this is also one of the thicker 0w-20 oils. Is there much viscosity difference between a thicker 0w-20 and a thinner 5w-30 or is a thicker 5w-30 a better option?
Direct Injection, Fuel Dilution, & Viscosity
- Thread starter GaryMX5
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In order that the collective wisdom of BITOG can be offered... we need additional details:
1. How much do you drive your cars?
2. Do you do a lot of cold weather driving, I know Colorado, but do you hibernate or go south for winter?
1. How much do you drive your cars?
2. Do you do a lot of cold weather driving, I know Colorado, but do you hibernate or go south for winter?
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What is a thinner 5w30 vs a thicker 5w30 ?
Also, find the owners manual for your Mazdas on some international website (Mazda Australia for example), and see what they recommend for Middle East. This is your "true" oil
.
Example for my Kia, from Australian manual (which is the International manual me think):
In the US manual, I only have the "A" range listed. 0w20.
The climate in these countries is not worse than Phoenix heat, and a winter in Iran is not warmer than one in Colorado. So it's not a climate thing. It's just that they don't have all the mpg requirements there.
Also, find the owners manual for your Mazdas on some international website (Mazda Australia for example), and see what they recommend for Middle East. This is your "true" oil
.Example for my Kia, from Australian manual (which is the International manual me think):
In the US manual, I only have the "A" range listed. 0w20.
The climate in these countries is not worse than Phoenix heat, and a winter in Iran is not warmer than one in Colorado. So it's not a climate thing. It's just that they don't have all the mpg requirements there.
You won't find a consensus opinion on this subject. The "thickies" here will say, use the thicker oil. They may even recommend 40 weight. Other people are against using anything not called out in their owners manual.
You may want to do an oil analysis, to see if your use case shows fuel dilution.
My Civic is famous for fuel dilution, but for the most part, I have stayed with the thin 0W-20. Or, I mix half and half with 5w-30. Why? Because my use case is short driving, and the engine doesn't get very hot. I'd rather error on the side of more flow from the thin oil, but then change it at 6 month intervals. Honestly, though, I don't think it matters much if at all. Mazda engineers know if their engines are fuel diluting, and yet they have speced the thin stuff. The engine doesn't care much either way.
You may want to do an oil analysis, to see if your use case shows fuel dilution.
My Civic is famous for fuel dilution, but for the most part, I have stayed with the thin 0W-20. Or, I mix half and half with 5w-30. Why? Because my use case is short driving, and the engine doesn't get very hot. I'd rather error on the side of more flow from the thin oil, but then change it at 6 month intervals. Honestly, though, I don't think it matters much if at all. Mazda engineers know if their engines are fuel diluting, and yet they have speced the thin stuff. The engine doesn't care much either way.
Each car will be driven about 7500 to 9000 per year based on the use of vehicles they replaced. Each will probably make at lease two round trips from Denver to Dallas per year. One or the other will make a trip to Ohio and back per year. They will not be garage queens and are driven year round. Both are AWD for good reason!
Both are normally aspirated.
5w-30 is referenced in the owners manual as an allowed oil in several countries excepting the U.S. probably for CAFE reasons.What is a thinner 5w30 vs a thicker 5w30 ?
Also, find the owners manual for your Mazdas on some international website (Mazda Australia for example), and see what they recommend for Middle East. This is your "true" oil
Example for my Kia, from Australian manual (which is the International manual me think):
View attachment 302494
In the US manual, I only have the "A" range listed. 0w20.
The climate in these countries is not worse than Phoenix heat, and a winter in Iran is not warmer than one in Colorado. So it's not a climate thing. It's just that they don't have all the mpg requirements there.
only would be my guess.
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Then you can use it.
It was the same rabbit hole for me, eventually I went for Motul 0w20 from FCPEuro for my next oil change. Just because that's what they have, and I'm trying ot figure out a process to go with their "free" oils. They are a driving distance away from me so it's doable.
I might look into 5w30 or 0w30 in the summer, but for now 0w20 it is.
It was the same rabbit hole for me, eventually I went for Motul 0w20 from FCPEuro for my next oil change. Just because that's what they have, and I'm trying ot figure out a process to go with their "free" oils. They are a driving distance away from me so it's doable.
I might look into 5w30 or 0w30 in the summer, but for now 0w20 it is.
I have run 0w-40 and 0w-30, and 5w-30. I've settled on the HPL 5W-30. If my wife still short tripped it every day like when she drove to work, i'd go 40.
The automotive manufacturers know all the different places people live, all the different ways they drive and that fuel dilution occurs. They make their oil specifications with all these things taken into account.
Ali
Ali
Mazda's engines don't seems to be nearly as prone to fuel dilution as other manufactures. On my CX-50, I haven't had any concerning amount of fuel dilution. My wife's PFI Civic usually has more fuel dilution than my GDI CX-50.
You can use any grade you want as long as the winter rating is appropriate for your expected starting temperature. There's no concern about "flow", if the oil can be pumped (winter rating) then it will flow.
Fuel dilution is never good for the engine, HPL has had a few good posts on this. Shortening the OCI can help along with using a higher grade of oil. It's really not about the viscosity anyway, but more about the HT/HS. ESP mentioned above has an HT/HS of at least 3.5 and might be a good option.
Fuel dilution is never good for the engine, HPL has had a few good posts on this. Shortening the OCI can help along with using a higher grade of oil. It's really not about the viscosity anyway, but more about the HT/HS. ESP mentioned above has an HT/HS of at least 3.5 and might be a good option.
My '17 does. Cold weather, short trip, its severe. Mazda may have fixed that issue by now.
I mean, any engine given the right situation will put fuel into the engine oil.
I know Mazda updated the 2.5L for the 2018 Mazda CX-5 and some of the updates included higher injection pressure, revised injector spray pattern, and injector that could pulse up to 3 times per intake stroke instead of just 2 times. Those changes definitely could have improved fuel dilution compared to older iterations of the engine.
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And then they add the mandated mpg requirements and check how close to these oil can get them without the engine blowing.
Patman
Staff member
No, M1 ESP 0w-30 is not on the low end of the 30 grade range, it’s on the high end actually, at 12.0 cst at 100c and it’s HTHS is not 3.0, it’s 3.5.
An example of something on the low end of the 30 grade range would be something that is a bit under 10 cst at 100c with an HTHS around 3.0
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