2019 GTR 2.5T Oil Dilution

I've been changing my oil since I bought this car. Currently has 19k miles. During the early December oil change I noticed the oil that got on my gloves was separating. It was having trouble holding a film. I noted it and changed my oil two weeks ago at 3,500 miles and sent my oil to Oil Analyzers. They confirmed that I do in fact have an oil dilution issue. I use Amsoil Signature 5W-30 /w an OEM Mazda filter.

Anyone else have this issue? If so did you get it resolved or is this the curse of having a high boost engine? Anything I should ask them to do? I'm bringing it in on Thursday (3/25). I'm at least going to insist on a compression test and test the fuel injectors.

My report is attached. Thanks!
 

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@crimeariver reported an oil dilution problem on his 2019 CX-9. Just like you, they had a UOA performed, then approached Mazda with the issue. The cause was a defective fuel injector, which was replaced under warranty.
 
I believe one other regular on this forum reported an oil dilution problem or their 2.5T, but I don't remember if they own a CX-5 or CX-9. In any case, just like you, they had a UOA performed, then approached Mazda with the issue. I believe they discovered the cause to be defective fuel injector, which was replaced under warranty.
Yeah I read that thread, in October 2020 he reported having the same issue even after the injectors were replaced.
 
Yeah I read that thread, in October 2020 he reported having the same issue even after the injectors were replaced.

Ah yes I see that now. He last visited the forums at the beginning of this month, so hopefully he was able to work something out with a new dealer or Mazda Corporate. Last I read, the dealer he was working with apparently stopped communication.
 
Do you live in colder climates? How's your driving style? Many short trips? Long idles? Never rev pass 4k rpm? And did you ask what is "normal" %age? Also one of the explanations was excessive blow-by. Maybe try to install an oil catch can?
 
Do you live in colder climates? How's your driving style? Many short trips? Long idles? Never rev pass 4k rpm? And did you ask what is "normal" %age? Also one of the explanations was excessive blow-by. Maybe try to install an oil catch can?
No I live in the southeast but it has been wintery.

Spirited, I don't redline but I enjoy the turbo. I probably do rev past 4k sometimes.

No to long idles.

I take my car out twice a day. The first trip is 22 miles round trip. The second trip is 4 miles round trip

Normal is below 2%

This might just be a byproduct of the boost. Even the computer recommends really short intervals and the oem oil is synthetic. I think the normal none flexible interval is 7.5k
 
All direct injection engines have some degree of oil dilution. My previous vehicle a 2015 Kia Sportage NA 2.5 liter had it and it was quite evident (1/4 liter over full mark) in the winter months where it gets to -20 F here. I asked the dealer about it and they said their vehicles do not suffer from oil dilution. A dealer that lies, who would have guessed. I sold the Kia and purchased a 2019 CX5 (in part) because Mazda actually recognizes that it's vehicles can experience oil dilution and put out a bulletin on the subject. I attached the bulletin for those that wish to view it. I'm old school and change my own oil and check it regularly. I contacted Mazda Canada and asked if I should fill the oil according to the dipstick or owner's manual. Their reply was fill according to the owner's manual and "In response to your inquiry, the oil level, when inspected hot, should read half way between MIN and MAX." I've experienced 2 winters with my 2.5 liter NA Mazda engine and the oil level has never exceeded the full mark since following Mazda's oil fill level recommendation. Our engines have a factory installed Mazda engine oil separator. Engine Oil Separators extract residues such as oil drops from the air before it is sent back to the intake manifold. The oil separator is attached to the side of the block so it doesn't experience freeze up like a catch can does in freezing climates. Hope this info helps someone.
 

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My 2008 BMW 3.0 twin turbo had zero dilution - when the oil was tested. Yes, direct injection. No “catch can” placebo either. Not saying it doesn’t happen, just that it isn’t necessarily universal.
 
I've been changing my oil since I bought this car. Currently has 19k miles. During the early December oil change I noticed the oil that got on my gloves was separating. It was having trouble holding a film. I noted it and changed my oil two weeks ago at 3,500 miles and sent my oil to Oil Analyzers. They confirmed that I do in fact have an oil dilution issue. I use Amsoil Signature 5W-30 /w an OEM Mazda filter.

Anyone else have this issue? If so did you get it resolved or is this the curse of having a high boost engine? Anything I should ask them to do? I'm bringing it in on Thursday (3/25). I'm at least going to insist on a compression test and test the fuel injectors.

My report is attached. Thanks!
4.2% fuel on an oil serviced for a half of the recommended oil change interval at 3,500 miles is significant enough causing the oil viscosity below the 5W-30 grade slightly. My feeling is the engine has “behavior” change by itself but not from driving habit or environment, as you just noticed that the oil drained was different from many previous oils drained. This means your 2.5T has just started significant oil dilution issue not long ago before last December, and now the problem is confirmed by the UOA. You definitely should pursue the issue with Mazda and want to get the problem resolved soon under warranty.

Direct injection or not, from many UOAs posted in our forum, fuel content has never been an issue although most UOAs are from 2.5L NA of course it’s a Di engine. They usually show 0.5% of the fuel which is well below the 2% threshold. The only UOA showed possible oil dilution issue with a borderline 2% is from a SkyActiv-D 2.2L diesel which historically is having oil dilution issue.

SkyActiv Oil Analysis Thread
 
I see that the wear values are good and that's what's important-YES?
Yes, but the oil tested had only been used for 3,500 miles and 3 months. And the viscosity is below the grade too, in addition to significant fuel content.
 
4.2% fuel on an oil serviced for a half of the recommended oil change interval at 3,500 miles is significant enough causing the oil viscosity below the 5W-30 grade slightly. My feeling is the engine has “behavior” change by itself but not from driving habit or environment, as you just noticed that the oil drained was different from many previous oils drained. This means your 2.5T has just started significant oil dilution issue not long ago before last December, and now the problem is confirmed by the UOA. You definitely should pursue the issue with Mazda and want to get the problem resolved soon under warranty.

Direct injection or not, from many UOAs posted in our forum, fuel content has never been an issue although most UOAs are from 2.5L NA of course it’s a Di engine. They usually show 0.5% of the fuel which is well below the 2% threshold. The only UOA showed possible oil dilution issue with a borderline 2% is from a SkyActiv-D 2.2L diesel which historically is having oil dilution issue.

SkyActiv Oil Analysis Thread
The only difference is that mine is a 2.5 T, it could be the boost is allowing for more blow by. It got me wondering if that's the reason Mazda specced 5W-30 for the turbo engines, they're expecting some dilution in the change interval. A change interval of 7,500 miles on an OEM speced synthetic oil is making me believe this is a known issues for the engine and they mitigate it by requiring a higher weight oil and a smaller interval. I'm not making excuses for them though and I'm bringing the car in tomorrow with the OA test report.

The other person who reported an issue with oil dilution told me he just changes it more often now. The fuel injector replacement they did on his didn't help. I will update on what they tell me later this week. Maybe worth pushing for a new engine if this continues to be a problem?
 
All direct injection engines have some degree of oil dilution. My previous vehicle a 2015 Kia Sportage NA 2.5 liter had it and it was quite evident (1/4 liter over full mark) in the winter months where it gets to -20 F here. I asked the dealer about it and they said their vehicles do not suffer from oil dilution. A dealer that lies, who would have guessed. I sold the Kia and purchased a 2019 CX5 (in part) because Mazda actually recognizes that it's vehicles can experience oil dilution and put out a bulletin on the subject. I attached the bulletin for those that wish to view it.
But based on many UOAs posted here, at least the direct-injection 2.5L NA doesn’t suffer oil dilution problem often. I did see a couple of oil-rising reports during the winter time before but that were in earlier years.

I'm old school and change my own oil and check it regularly. I contacted Mazda Canada and asked if I should fill the oil according to the dipstick or owner's manual. Their reply was fill according to the owner's manual and "In response to your inquiry, the oil level, when inspected hot, should read half way between MIN and MAX." I've experienced 2 winters with my 2.5 liter NA Mazda engine and the oil level has never exceeded the full mark since following Mazda's oil fill level recommendation.
If you put in 4.8 quarts for oil change on your 2.5L NA according to the spec stated in owner’s manual, yes you’ll get the oil level to the half between Max / Full and Min / Add marks on the dipstick. In your case you’ll never get to the Max / Full mark when you check the oil level hot or cold, as that requires 0.5 quart of fuel in your oil which means it ha10.5% of fuel content!

For 2.5L most DIY people here put in 5 quarts of oil mainly for convenience. Some including me put in ~5.3 quarts making sure the oil level is at the Max / Full mark on the dipstick after the oil change for greater safety margin. We haven’t seen any oil level rising reports recently. And my 2.5L actually uses oil about 0.3 ~ 0.5 quarts per oil change, and that’s why I want oil level to be at Full mark with greater safety margin, and don’t need add oil between oil changes.

BTW, most dealers over-fill the oil above the Max / Full mark for oil change all the time!

Our engines have a factory installed Mazda engine oil separator. Engine Oil Separators extract residues such as oil drops from the air before it is sent back to the intake manifold. The oil separator is attached to the side of the block so it doesn't experience freeze up like a catch can does in freezing climates. Hope this info helps someone.
Mazda’s factory oil separator may be designed for catching excessive blow-by like a catch can, but in the real world it seems to be not doing a good job for the purpose. While taking out the intake manifold, people would find plenty of oil residue in manifold and carbon deposit on intake valves even at very low mileage, but the oil separator is bone-dry! On the other hand when people installed the catch can, they reported catching much oil residue from blow-by.

Video Cleaning Intake valves CX 5 Skyactiv Gasoline engine
 
Just because an oil analysis indicates no gasoline or very little in the oil does not mean that oil dilution does not occur. Vehicle operation in warm weather or long enough to properly warm the engine in a cold climate will cause gasoline that gets by the rings to evaporate and be burnt by way of the PCV system. Oddly enough if you live in a cold climate where the temperature is constantly below zero and gets down to -20 Fahrenheit for days on end you'll find that (unless you devote time to frequently emptying) a catch can which collects oil and water vapor it may freeze and could possibly cause damage due to a plugged PCV system. I live in a cold climate and do many short runs in the winter so I have to be mindful of oil dilution and a catch can is out of the question for me. I just keep an eye on my oil level and will change it if I feel it's necessary. Haven't had to do that with my Mazda yet. The Mazda oil separator is not perfect just as catch cans are not perfect but it's better than nothing. If I were to notice a sudden increase in oil level without a change in driving habit I would suspect a fuel supply problem such as a bad injector or increase in pulse width. I personally dislike gasoline direct injection engines, they are dirty problem prone engines that sacrifice long life for a bit of fuel economy and better emission control.

https://www.sae.org/publications/technical-papers/content/2015-01-0967/
 
Just because an oil analysis indicates no gasoline or very little in the oil does not mean that oil dilution does not occur.
There’re many UOA reports in that thread, not just one. All of them are well below 2% on fuel content, mostly are at ~0.5%. The only one showed 2% fuel content is a 2.2L diesel.

Not saying the oil dilution won’t occur on SkyActiv-G 2.5L or 2.5T. It should be rare on 2.5L based on many UOA reports. Operating in cold environment will have more possibility on oil dilution issue. With additional turbo, the 2.5T more likely will have oil dilution issue too.
 
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My Mazda dealership has had the car for about two days now and so far their position is:
1. It's not hindering drive ability
2. There are no codes being thrown by the computer
3. Because of 1 and 2 everything is fine

The service manager admitted this is the first time he's ever seen something like this. This dealership has only been around for about five years though. I'm pushing for them to test the fuel injectors and do a compression test. He says he'll need Mazda HQ permission, should I push for anything else or just request to speak to Mazda directly?
 
My Mazda dealership has had the car for about two days now and so far their position is:
1. It's not hindering drive ability
2. There are no codes being thrown by the computer
3. Because of 1 and 2 everything is fine

The service manager admitted this is the first time he's ever seen something like this. This dealership has only been around for about five years though. I'm pushing for them to test the fuel injectors and do a compression test. He says he'll need Mazda HQ permission, should I push for anything else or just request to speak to Mazda directly?

I would suggest that you push them to escalate to Mazda HQ. Then contact Mazda HQ yourself. Like many others, I have a hard time trusting any dealer to do what they're asked to do.

I'd try to approach this as level-headed as possible. If it were me, I'd explain to Mazda HQ what my concerns are, and I'd be ready to provide the UoA if necessary. I'd suggest that a fuel injector test and compression test would be a much more cost-effective, proactive approach vs. waiting for the dilution problem to get worse and potentially result in irreversible engine damage.
 
Yeah so I got the car back today. In the three business days they had the car they did a scan for codes, drove it and changed the oil. They also contacted Mazda HQ who said because everything seemed A OK they weren't going to pay for any other tests.

So I got the number for Mazda HQ and I'll have to talk to them directly.

In the meantime I think I'm going to switch oils. Any thoughts on Castrol Edge 5W-30 C3? It's "made" for European cars. What I like is the viscosity at 100 C is rather high for this grade at ~12 cSt. On it's product data page it list Mazda as a "trusted OEM."
5W-30 C3

The 5W-30 US version viscosity is around 10.4 cSt, so not much better than Amsoil. The Mazda Idemitsu 5W-30 oil is also around ~10 cSt at 100 C, so not much better.

I think if they do nothing I'll switch to a higher viscosity 5W-30 and change a little early.
 
Yeah so I got the car back today. In the three business days they had the car they did a scan for codes, drove it and changed the oil. They also contacted Mazda HQ who said because everything seemed A OK they weren't going to pay for any other tests.

So I got the number for Mazda HQ and I'll have to talk to them directly.

In the meantime I think I'm going to switch oils. Any thoughts on Castrol Edge 5W-30 C3? It's "made" for European cars. What I like is the viscosity at 100 C is rather high for this grade at ~12 cSt. On it's product data page it list Mazda as a "trusted OEM."
5W-30 C3

The 5W-30 US version viscosity is around 10.4 cSt, so not much better than Amsoil. The Mazda Idemitsu 5W-30 oil is also around ~10 cSt at 100 C, so not much better.

I think if they do nothing I'll switch to a higher viscosity 5W-30 and change a little early.
That’s unfortunate but it’s expected. I guess you can keep doing the UOA monitoring the oil dilution condition like Silly Wabbit suggested, in the mean time try a different oil. I’d try newer SP / GF-6 oil next time such as Idemitsu SP/GF-6 5W-30 oil. And here is ILSAC GF-6 performance relative to GF-5 and API SN Plus performance:

1D84F5B3-3AD2-4E39-9638-0688D11CEA3A.png


And Idemitsu SP/GF-6 5W-30 oil claims the following improvements over GF-6 standard although many say they’re exaggerating:
  • 30% more protection against engine wear
  • 26-46% reduction in oil consumption for longer life
  • Up to 24% improved fuel economy
  • 90% more resistant to viscosity increases
  • Three to four times more protection against cold startups
  • 91% reduction in low-speed pre-ignition (LSPI)
  • 6% cleaner engine
 
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