Why do Engines Sometimes Burn Oil?

Sometimes, engines consume a lot more oil than they should. Why? There are many causes, including lubricant volatility, bore polish, leaking seals etc. So let's take a look.

Hi I’m Rafe Britton, the Lubrication Expert. I’m known within the industry for my YouTube channel and podcast, and I work with mid-size industrials improve their equipment uptime while reducing the cost of their lubrication program. I’m a mechanical engineer with 13 years of experience on both sides of the industry; both as an operator, and lubricant supplier. I hold a Bachelor of Aerospace Engineering and a Bachelor of Physics from UNSW.

Lubrication Expert is purposefully brand independent and sells no lubricant, filter, sensor or hardware. I’ve helped dozens of industrial clients upskill their workforce, reduce waste, improve reliability and take great strides toward their corporate sustainability goals. I serve on the Australian Lubricant Association technical committee to push the lubrication industry forward.

Industry doesn’t understand lubrication, and few people are left to teach them. This results in incorrect use of lubricants, contamination & machine failure, leaving reliability engineers frustrated with the state of their lubrication program. The ultimate consequence is more machine interventions, more waste, and more equipment downtime

What I offer is knowledge, and only knowledge. My clients gain access to my learnings both as an operator and industry insider – this includes the technical aspects of lubricant chemistry, degradation and contamination control, but also the commercial considerations so that you can better leverage your supplier relationships.

The result? A world-class lubrication program that optimizes for reliability, reduces waste and improves sustainability outcomes.

[scku]

2:25 bad valve seals…source of the good old “Bowtie Salute” (aka the “Chevy Salute”)

[LeakyWaders]

Just found your channel and been watching videos. Great stuff, man. Thank you.

[zeeosix]

Couple other possible reasons for oil consumption could be: 1) Sticking oil control rings that no longer push against the cylinder wall well enough due to running crummy oil too long, and 2) A badly designed PCV system that sucks too much oil vapor into the intake manifold, which would become worse if the oil volatility is high.

[chippyjohn]

With aircraft engine, one of the reasons they have dual spark plugs is incase one fowls due to oil consumption (as well as redundancy for lead fowling, coil loss and other reasons). My understanding is that air cooled engines especially those with steel cylinders and aluminium pistons suffer from increased oil consumption due to larger cold clearances (and other reasons). Not tested yet, I imagine oil consumption would be severely reduced with a turbocharged engine, even if just slightly, as there will never be a vacuum in the combustion area. The positive pressure differential would also stop oil entering the valve guides most likely. Of course you have the possibility of oil entering from the turbo if the oil return was to become restricted. Just rambling. A lot of the aircraft engines either get fowling or hotspots because of oil ingress, so the topic of keeping it out is important to me. A lot of these engines are naturally aspirated still so they do not have the benefits of the pressure differential. I was thinking of having a fine white filter after the aftercooler to capture and assess any oil that gets through the turbo, haven't seen that done, but Im sure it has been in testing facilities. I'm also surprised that gapless rings are not more commonly used on engines. Thanks for the video. When My patents come In I'll help you out.

[lesliedsouza]

Good picture of ring twist, function, during strokes. Word is, Top & second rings are slightly different?
Top, more compression holding? Second ring, doing some, (backup) compression? A bit more, oil control?
Major, oil control, of course, the lowest, oil control ring. You could do pics of these, in another vid?
Here's a thing. In the ongoing drive, for better fuel economy & reduced emissions -
Thinner oils & lower piston ring tension, have been used, to reduce frictional losses. Ok, when pressure above,
'Cos pressure firms the ring, against the cyl wall.
On the suction stroke, not enough tension, against cyl, wall? Vacuum draws oil up :)

[tonybennett]

As a apprentice 50 years ago was told by a mechanic when fitting compression rings with a cutout groove think of sex ... When you're in you're up and when you're out you're down.

[hanynowsky]

Ond of the main reasons is = clogged piston oil drain holes.
Toyota 2AZ-FE
BMW N52b25
If it s not too late, these can be unclogged using 3 oil flushes with BG EPR 109

[zzman]

Those darn low tension rings are a curse.

[hamzaburghol]

Thank you very much for this lecture. Indeed, you are a doctor in this field. But I have a question, please, dear. What is the alternative solvent for sulfur acid in the setting of the bitumen?

[durgimstingetium]

Manual book says I should use 5w30 oil.
The engine has direct injection and turbo, plus with my city's temperature reaching 40 c, and constant traffic, my car consume oil 1 liter / 2000 km.

Do u think i can change into thicker oil auch 5w40?

[jantelow]

If the compression, the crankcase ventilation and the valve seals are ok, could it be the oil rings that are worn/damaged which are the reason that the engine uses a lot of oil? The engine in my car has been run hot/overheated once by the previous owner.

[josecuevas]

You forgot oil via PVC system, oil being pushed into the intake manifold due to exissive blow-by due. Moreover, blow-by caused by a combination of upper cylinder ware, espicaly at the pistion thurst side, during the power-stroke event, and pistoin ring were.
All theise add up to a total ware.
Another problem is that the piston rings stick to tbe piston and don't excert enough pressure against the cylinder wall, due to lack or extended oil changes. Actualy all the possiblites of exssive oil consumption are mostly due to lack of and/or not enough or extending oil changes.
Some time's due to bad MFG design or metalogy on engine block or piston ring or a combination of both.

One more valve gide ware is another source of oil consumption.

[mohdfaizal]

I habe question..Can engine running with high coolant temperature causes oil consumption?

[tt]

Hello everybody,
I 'm wondering if it is possible to soak in some cleaner into the cylinders through the spark plugs holes, let it work awhile and run the engine to working temperature, would it benefit to free those piston rings ?
Just an idea I had one day after looking Inside the cylinders while changing my spark plugs.
Thanks for getting back to me.
Tigo.

[jasonligo]

I have to wonder if using a product like CRC intake valve cleaner will wash the oil out of the cylinder walls causing increased rate of wear. Anybody have any idea if it does?

[wahidabbas]

your voice is too slow to catch . . . i suggest to please keep your volume increased

[matsinkal]

Usually its because they are Mitsubishis

[nerdify]

Possible oil consumption route number 3: your engine is a spawn-of-satan 2 stroke and burns all its oil, by design. Curse the darned things!