Oil consumption, dirty exhaust and an answer from a Mazda mechanic

[BGChicago]

So I checked my oil level today and for 7000 miles it dropped from 3/4 Of the Max to the Min point.
My exhausts are dark dirty like it's a diesel motor.
I stopped by the dealer and talked to one of the mechanics and he tells me this:
To be considered abnormal, oil consumption must be 1 quarter per 1500 miles. WTF?


Do you guys know what's the volume difference between the min and max notch on the oil dip stick?
Should I be worried about the oil loss I got?
How are your exhaust pipes?
2013 2.0 Skyactive G Manual 27k miles, Mazda GNS-5 oil since new

 

[Nodnerb]

My exhaust pipes always have to be cleaned. Not abnormal. Never experienced much oil loss though. Maybe its the difference between measuring too soon after stopping the engine and after it has been sitting?

 

[erhayes]

Down shifting to reduce vehicle speed can cause increased consumption.

 

[BGChicago]

Measured cold, after 5 hours rest.

 

[BGChicago]

Down shifting to reduce vehicle speed can cause increased consumption.

Is that true or just theory? Prove?
I down shift a lot.

 

[CX-SV]

No comment on the downshifting to reduce speed increases consumption.

But the criteria "to be considered abnormal, oil consumption must be 1 quart per 1500 miles" is typical for any major automaker.

 

[BGChicago]

Oh and FYI, I don't downshift into crazy RPMs, but keep it on gear as long as I can when approaching stop instead of shifting to neutral.
For example, I go with 50 mph on sixth, I see a red light in front of me, I let my foot off the gas and when RPMs hit 1500 downshift to 4th or 3rd and then neutral when RPMs hit 1500 again.
Is that considered down shifting?

 

[MikeM.]

How are your exhaust pipes?

I've never seen an internal combustion engine that did not have some black soot around the inside of the exhaust pipe(s). Even propane powered vehicles produce some amount of soot over time. It's just a fact of life with internal combustion engines.

 

[BGChicago]

I've never seen an internal combustion engine that did not have some black soot around the inside of the exhaust pipe(s). Even propane powered vehicles produce some amount of soot over time. It's just a fact of life with internal combustion engines.

In contrast, i've seen many. May be not no soot but not as bad as my CX-5. And back in the 90s I had a Jetta which exhaust pipe was so clean that it had rust on the inside.
I don't expect it to be metal clean, by like I said - mine looks like it's a diesel motor.

 

[erhayes]

My comment about downshifting can cause increased oil consumption is real. The habit caused a high vacuum in the cylinder which can cause oil to be sucked up past the oil control rings. Depends on the engine design and condition of the engine. According to BGChicago, this is not a factor. Ed

 

[jaman_ca]

The other week I changed the oil my self for the first time; the first two were done at the dealer. When I drained the oil, it was about 4.0L, the manual says 4.2L with an oil filter change. I'm not in the habit of checking the oil level on a new car, so I don't know if it changed much since the dealer visit but looks like it was down if the dealer did fill it up.

I'll have to keep a closer eye on it now and see if it drops.

One annoying thing is that it's damn hard to read the oil level when it's fresh and clean. One side of the dip stick says half-full (mid-way between min and max) and the other side looks like it's overfilled. I'm guessing there is about a 1L difference between min and max, but that's just my estimate when I was pouring it.

 

[phoned]

Yup, it's brutally hard to see how much is actually in there. Our other Mazda is just as bad.

 

[BGChicago]

... According to BGChicago, this is not a factor. Ed

What do you mean by this? Because the engine is still new or because my downshifting isn't "aggressive "?

 

[jaman_ca]

What do you mean by this? Because the engine is still new or because my downshifting isn't "aggressive "?

I'm pretty sure he meant that your downshifting isn't aggressive enough - which it isn't. It's not like you're routinely revving to +4K on downshifts.

Any time you have the throttle closed and are above idle you'll have high vacuum which might cause increased oil consumption. Downshifting simply means that you are in that regime for a longer period of time than if you would have let the engine go to idle (i.e., coast in neutral).

 

[BGChicago]

I have always drive manuals, owned 5 car in my life and this is the first brand new one and the first one to burn oil. Before that I had Civic Si which I down shifted aggressively but I was changing the oil every 3K miles so it's hard to notice oil consumption.

I guess I will have to live with it. At least it's super economical on gas and I guess I will have to live with it.

 

[CX-SV]

To clarify, did it use 3/4 of a quart in 7000 miles?

 

[V8toilet]

So I checked my oil level today and for 7000 miles it dropped from 3/4 Of the Max to the Min point.
My exhausts are dark dirty like it's a diesel motor.
I stopped by the dealer and talked to one of the mechanics and he tells me this:
To be considered abnormal, oil consumption must be 1 quarter per 1500 miles. WTF?


Do you guys know what's the volume difference between the min and max notch on the oil dip stick?
Should I be worried about the oil loss I got?
How are your exhaust pipes?
2013 2.0 Skyactive G Manual 27k miles, Mazda GNS-5 oil since new

My first 2013 CX5 I had the 2.0 motor and it never used any noticeable amount of oil but there was a noticeable amount of black soot around the tailpipes. I've noticed that with my 2.5 in my 2014 the oil level did drop some for my first oil change, probably about as much as yours. Also soot in the tailpipe seems to be common to all GDI engines and I think has something to do with increased particulates during combusion with direct injectioned engines. So I think the very minimal oil consumption and tailpipe soot you've experienced may just be normal and not unique to Mazda.

Think about how thin that 0-20 synthetic oil is. It's a miracle that more doesn't get by the rings especially with all the engine braking subjected to this engine by the direct clutch auto or engine braking in a manual. If mine only uses 1/2 quart or less in 7000 miles than I consider that acceptable.

 

[GAXIBM]

In the miller cycle phase of the engine management (light/no loads) it leaves the intake valves open longer to reduce the vacuum and the resulting pumping loss - so less vacuum and less sucking of oil past the pistons. I am not sure if you are in the engine braking phase if the vacuum goes back up to produce higher engine braking or not but I suspect it does not.

 

[BGChicago]

I changed the oil today and found out that it was dripping from the drain plug. So probably oil consumption is less than originally reported.
I changed the washer with a copper one for better seal.

 

[V8toilet]

In the miller cycle phase of the engine management (light/no loads) it leaves the intake valves open longer to reduce the vacuum and the resulting pumping loss - so less vacuum and less sucking of oil past the pistons. I am not sure if you are in the engine braking phase if the vacuum goes back up to produce higher engine braking or not but I suspect it does not.

That a very good point!