2.5L Oil level fluctuation

Hi garycar

Just wait till you get the Skyactiv diesel in the U.S. You will need to check the oil level each week for the oil level rise as a result of unburnt fuel being returned to the engine due to DPF regeneration. As soon as the oil level gets near the "X" mark on the dipstick ( or the oil warning light appears) you have to have a full drain and refill with fresh oil at your own expense or if Mazda is feeling particularly kind on that particular day have it done for free. It's not covered as a warranty requirement. (At least not in the UK).

Jonno21

The fuel in oil on diesel models was addressed via a software update about 3 years ago.

I'm onto my second CX5 2.2 diesel and have never had an issue with "making oil". The first was a 2013 GT, and my current is a 2015/16 Akera.

My brother has a 2012 CX5 GT diesel and he initially had the issue, but since the sw update no further problems on a car that is 90% driven around town.

Re the issue of the 2.5 petrol engine "making oil", it just seems to me a big stretch that so much fuel gets past the rings that it dilutes fuel really quickly and by such significant amounts. If the rings were that bad or the engine was being overfuelled so much, then surely, the car wouldn't run at all well.

I think there is a fair chance that the problem lies somewhere else. I would be looking at any part of the entire fuel system where fuel can physically get into the crankcase. Fuel pumps, emission system, and any related lines that vent into the crankcase.....

Let me tell you my rationale for this - I run Suzuki 4 stroke outboards and am a mod on their forum. It's quite common to hear of this "making oil" issue on that forum, and, like here, most people point the finger at blow-by due to engines that are run for long times at idle speed of just above. Lots of guys troll lures and baits for hours on end with the engine just idling along.

But the real cause is quite simple in 95% of those cases, there is a tube from the VST that is part of the emissions system and is designed to take fuel vapour from the VST to the crankcase, but when the VST float is badly adjusted, or the needle is stuck, fuel level in the VST gets excessive and guess where that excess fuel goes? Yep, straight through that vapour tube and into the crankcase. The usual root cause is dirty fuel causing a blockage in the VST.

The other 5% were from crank driven fuel pumps that corroded and then leaked fuel direct into the crankcase.

Now, that exact situation may not arise for the Mazda engines, but fuel getting into the crankcase from some element of the fuel system or evaporative emission seems far more likely than massive amounts of fuel getting past piston rings to me.

Just a thought.....
 
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Let me tell you my rationale for this - I run Suzuki 4 stroke outboards and am a mod on their forum. It's quite common to hear of this "making oil" issue on that forum, and, like here, most people point the finger at blow-by due to engines that are run for long times at idle speed of just above. Lots of guys troll lures and baits for hours on end with the engine just idling along.

But the real cause is quite simple in 95% of those cases, there is a tube from the VST that is part of the emissions system and is designed to take fuel vapour from the VST to the crankcase, but when the VST float is badly adjusted, or the needle is stuck, fuel level in the VST gets excessive and guess where that excess fuel goes? Yep, straight through that vapour tube and into the crankcase. The usual root cause is dirty fuel causing a blockage in the VST.

The other 5% were from crank driven fuel pumps that corroded and then leaked fuel direct into the crankcase.

Do these issues occur on late model motors?

I bought a 20HP Suzuki back in April of this year.
 
Any leak or problem in the evap system would set a dtc and check engine light. The system monitors this entire system in values of milli bar, so your theory is not valid for my cx5.

Also I never said it was "making oil", just increased oil level. Also, the fuel blowby does impact fuel economy and drive ability. It is about >=1/4 qt over 600 miles, give or take.

Also, since it went down during the highway trip and we data logged practically every possible sensor and variable and it came back normal, I'm confident in my and my master techs ability to diagnose and solve any problem.

Fyi, if your gas cap is loose or the seal is leaking, it we will set a dtc and trigger ce light.

Also, there is a tsb on fluctuating oil levels for the 2.0 and by default I include the 2.5.

Those are my and my master tech's conclusions and I'm not gonna keep defending them. If you don't agree fine, I really don't care.

I'm only trying to help other people who have the same "REAL" condition.

And that's all I gotta say about that!
 
No need to get all defensive..... I was just offering an alternative view.

FYI the term "making oil" is used to describe this exact situation. Oil levels increasing and diluted with fuel, with no immediately obvious reason.

I was simply saying that it might be worth a look elsewhere. That's all. Chill, bro!

I hope the sw update youre expert techs have done solves the problem.
 
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Do these issues occur on late model motors?

I bought a 20HP Suzuki back in April of this year.

Can do, but easily prevented. Just install a Racor style water separating fuel filter between the tank and engine. Change element annually. As I mentioned the vast majority of these issues are caused by dirty fuel- so keeping the fuel supply fresh and clean is the best prevention. The Racor filters are kind of standard fitment on larger engines but no so much on the smaller hp - but they should be considered as essential equipment.
 
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FWIW.....I'm the one who started this thread. If you read post #1, I did do an oil analysis that show around +10% fuel. The dealer was fishing and tried all kinds of things and ended up changing out the HP fuel pump. They said it was leaking internally. At the time it seemed to stop fluctuating, but then it also got warmer outside.
Did oil change in the summer and everything looked ok. NO level fluctuations for summer driving. Sent another sample out but the company did not provide fuel dilution numbers, said it was not an issue so they don't list them (don't ask why). Did another oil change just before winter and oil looked great, nice gold color, no level changes for 8000 kms, all warm weather driving, so didn't bother with oil test.
But I checked the other day, and it was a good 1/4" above the full mark. All levels are always checked on cold engine, sitting in garage all night. We went on a 300 km road trip, and noticed it dropped almost to the full mark. So after the last couple months of cold weather, slow driving around town on snow/icy roads, the fuel problem is back. Since Mazda says this is perfectly normal, I just won't check the oil any more, it only aggravates me. This "new" car feel left a long time ago even though we only have 45,000 kms.
Sorry but in all the vehicles I have owned over the last 30 years, this is the first time I have seen this issue, so much for technology. Add the fact my dealer doesn't know how to change a spark plug in a lawn mower doesn't help either (oops sorry off track there).
Anyways, I have a list going for warranty repairs so I'll have to mention that TSB, maybe that will help.
 
FWIW.....I'm the one who started this thread. If you read post #1, I did do an oil analysis that show around +10% fuel. The dealer was fishing and tried all kinds of things and ended up changing out the HP fuel pump. They said it was leaking internally. At the time it seemed to stop fluctuating, but then it also got warmer outside.
Did oil change in the summer and everything looked ok. NO level fluctuations for summer driving. Sent another sample out but the company did not provide fuel dilution numbers, said it was not an issue so they don't list them (don't ask why). Did another oil change just before winter and oil looked great, nice gold color, no level changes for 8000 kms, all warm weather driving, so didn't bother with oil test.
But I checked the other day, and it was a good 1/4" above the full mark. All levels are always checked on cold engine, sitting in garage all night. We went on a 300 km road trip, and noticed it dropped almost to the full mark. So after the last couple months of cold weather, slow driving around town on snow/icy roads, the fuel problem is back. Since Mazda says this is perfectly normal, I just won't check the oil any more, it only aggravates me. This "new" car feel left a long time ago even though we only have 45,000 kms.
Sorry but in all the vehicles I have owned over the last 30 years, this is the first time I have seen this issue, so much for technology. Add the fact my dealer doesn't know how to change a spark plug in a lawn mower doesn't help either (oops sorry off track there).
Anyways, I have a list going for warranty repairs so I'll have to mention that TSB, maybe that will help.

That sucks.

That said, my 2015 has about 56K miles on it now, and still feels new when I vacuum and wash it. What about yours "does not feel new"? Now, I will admit, I did not get my CX-5 new, but owned a new 370Z and new C6 Z06, so I know what "new" feels like in a vehicle.

My CX-5 still shifts snappily, does not rattle, etc. and to me, that is "new". No appreciable interior wear.

I will have to keep an eye on my engine oil levels, and may send some off for analysis this next oil change (dealer used their oil, I prefer a different oil, so I'll wait and do the UOA on MY oil, since the dealer thing was a mistake and likely won't happen again, so the numbers won't mean much).
 
My oil catch can gets a good dose of blow by. When I change my oil next week I'll dump into a container ( about 5ooo miles ran)
 
Hi Mazdman,

garycar here. Please let me know of any updates with your rising oil levels in cold weather. Some people have said that I am imagining this and that it is not fuel, but I know its fuel. Unfortunately, but good to know that there are others who have the same issue. If you discover a solution, I would like to know. It is winter here in Brandon, Manitoba now and I check my oil daily and every day it rises just a little because of the short trips in town. Fortunately I have had some longer trips to go on recently which burned off the fuel and brought the level down. I also put a cover on the front of my CX and it seems to help. I guess the motor heats up quicker and burns off the fuel. I still have yet to find a solution to the problem, and this is the third winter. When the weather warms up, there will be no problem, but that is months away. On it goes. All the best to you.
 
garycar: You might try running Premium for a while.. some have stated this basically eliminates issue. I never travel less than 25 miles from a cold start so haven't noticed any noticeable level anomalies on mine. There was a small amount of fuel in my Blackstone test even though I don't drive short distances so it might be a problem if I was driving less than 10 miles per day.
 
garycar: You might try running Premium for a while.. some have stated this basically eliminates issue. I never travel less than 25 miles from a cold start so haven't noticed any noticeable level anomalies on mine. There was a small amount of fuel in my Blackstone test even though I don't drive short distances so it might be a problem if I was driving less than 10 miles per day.

Some say to use premium in the summer because of the warmer temps now there's a reason to use it in the winter. Too bad the price differential between 87 and 93 octanes is so high these days. It used to be only ten cents between 87 and 89. Then another ten cents between 89 and 93. I guess that premium costs more to make these days eh? Yeah, right....
 
Hi garycar,

I'll keep you updated. I had the PCM & TCM flashed to the latest versions. Haven't driven it much since then, probably about three hundred or so shortish, cold miles by the wife, but the level has seemed to stabilize just below the full mark. I'll have to check it again and again for a while, to be able to confidently say it made a difference.

As far as people saying premium will fix it, that's the worse thing you could do and would make our existing problem even greater and cause more problems like excess carbon on the back side of the valves and in the intake.

Octane is a measure of the resistance to detonation in the combustion chamber. It's harder to fully combust and spread an even flame front across the face of the piston, so the combustion event occurs smoothly and at the right time.

I own many high hp turbo sports cars and tune them to take advantage of high Octane and make more BHP.

Our cars are NOT going to benefit from 93 or 91, because they were designed and tuned for 87. I occasionally have run 89 and have seen no difference in performance or fuel economy.

I know we have a knock sensor, but if the engine isn't tuned to use 91 or 93, we get incomplete combustion and tons of carbon buildup. I have seen port fuel injected cars that weren't designed for premium, carbon up the valves so bad, that it would get cold misfires, etc in as little as 3000 miles. Our DI engines would be even worse.

It is more important to run different brands of 87 on a regular basis, because the additive packages are different and will help keep the wetted fuel parts cleaner.

All DI engines have a intake/valve carbon problem and it is exacerbated by the high blow by and crankcase crud that is dumped on the backs of the valves by the PCV system. That is why Toyota, Subaru and others are now combining port injection with direct. To keep the valves clean.

Our situation sucks, but I'm determined to find a fix. Those that chime in and say we're nuts or don't know what we're talking about, can keep their traps shut if they don't have anything constructive to add.

I was glad I found you! I was like WTF!!!

Happy new year and to a fix in 2017!
 
If you want to reduce the problem, cover about 3/4 of the air flow through the radiator to allow the engine to heat up faster during the cold weather time. This is what the big diesel trucks do with either a radiator cover or shutters to control the airflow.
 
My wife's CX-5 is seeing lots of short trips, and indeed the oil level goes up. Used oil analysis shows fuel dilution, as expected.
Reading about this I came across the condition that is called Low Speed Pre-Ignition, LSPI. Evidently, this only affects DI engines and is much more detrimental then regular pre-ignition that causes pinging. LSPI can't be detected by the knock sensor, so OEMs are dealing with it by dumping fuel under conditions that MAY cause LSPI, making it impossible to happen. Hence, most of the DI engines have fuel dilution problem, the fuel just burns off during long drives in fully warmed-up engine. No such luck for us short-trippers...
 
My wife's CX-5 is seeing lots of short trips, and indeed the oil level goes up. Used oil analysis shows fuel dilution, as expected.
Reading about this I came across the condition that is called Low Speed Pre-Ignition, LSPI. Evidently, this only affects DI engines and is much more detrimental then regular pre-ignition that causes pinging. LSPI can't be detected by the knock sensor, so OEMs are dealing with it by dumping fuel under conditions that MAY cause LSPI, making it impossible to happen. Hence, most of the DI engines have fuel dilution problem, the fuel just burns off during long drives in fully warmed-up engine. No such luck for us short-trippers...

Interesting, I'll have to check in to that.
Any pre-ignition should be and from my tuning experience has been worse in hot conditions, when air is less dense, hotter, etc and knock is more prevalent.
Engines love cool, dense air, especially turbos.
I'm a little suspicious about the no knock sensor can detect it part and they just dump fuel in if it might occur. In their obsessive quest for every mpg, I don't think they would blindly go into open loop, dump a bunch of extra fuel and risk cat damage, etc.
Our problem is during cold weather when knock, PI, etc is least probable, and goes away in hot weather when knock, PI, would be most probable.
Modern knock sensors are extremely sensitive to very minute inaudible small knock and pinging cycles. If they couldn't detect it on a DI engine, then the 2.5 Sky Active turbo engine would be screwed and it wouldn't have different HP ratings for different octane ratings.
A knock sensor is based on the piezoelectric effect. If you apply a force/displacement to it, you get a voltage and the inverse is also true. If you apply a voltage to it, you get a high force/small displacement output.
I've tuned many DI engines with a set of headphones tied into a knock sensor and you can clearly detect the onset of knock, even before a complete knock event occurs in a single crankshaft/eccentric revolution.
I say eccentric shaft, because the rotary engine is the least tolerant of any engine to any degree of PI, detonation and a single event can wipe out an apex seal, while a piston engine wouldn't be fazed.
Just my 2 cents.
 
My wife's CX-5 is seeing lots of short trips, and indeed the oil level goes up. Used oil analysis shows fuel dilution, as expected.
Reading about this I came across the condition that is called Low Speed Pre-Ignition, LSPI. Evidently, this only affects DI engines and is much more detrimental then regular pre-ignition that causes pinging. LSPI can't be detected by the knock sensor, so OEMs are dealing with it by dumping fuel under conditions that MAY cause LSPI, making it impossible to happen. Hence, most of the DI engines have fuel dilution problem, the fuel just burns off during long drives in fully warmed-up engine. No such luck for us short-trippers...

The hole keeps getting deeper and more stuff keeps coming out about this.. Click on the lubrication tab on this link and see what it says about moly oils
https://www.oronite.com/products/lspi.asp
 
That's good reading. Thanks for the info. However, it appears that the LSPI, GF-6 oils, papers, etc are geared more toward forced induction applications, where I'd expect and not NA applications like non-diesel CX-5's. Not saying it doesn't apply, just geared more toward higher combustion pressures and temps.

That being said, it is interesting that calcium promotes LSPI and molybdenum inhibits it.

I've always used M1 0W20 EP since day one. Have to head over to BITOG, etc and see the comparison of the M1 & Mazda moly additive packages.

Anyone experiencing this using the Mazda moly oil?

The hole keeps getting deeper and more stuff keeps coming out about this.. Click on the lubrication tab on this link and see what it says about moly oils
https://www.oronite.com/products/lspi.asp
 
The hole keeps getting deeper and more stuff keeps coming out about this.. Click on the lubrication tab on this link and see what it says about moly oils
https://www.oronite.com/products/lspi.asp
"Molybdenum compounds, for example, not only provide frictional benefits, but also have been shown to decrease LSPI when used at high levels."

I guess this's part of reason why Mazda recommends Mazda Moly oil. Our 2016 CX-5 has been using Mazda Moly oil since new, and it's mainly for wife's daily local commute with 10 miles one way to work. I have only noticed some oil consumption issue, not oil raising issue.
 
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