Sudden Oil Consumption Causes?

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Originally Posted By: Joe90_guy
One very last thing I'll say that when people talk about oil, they invariably talk about the NOACK test.

How would you test for and quantify volatility? I always have had a mixed feeling about Noack, since it wasn't unheard of to have no measurable consumption back in the day when Noack would be in the 25% range.
 
Originally Posted By: Garak
Originally Posted By: Joe90_guy
One very last thing I'll say that when people talk about oil, they invariably talk about the NOACK test.

How would you test for and quantify volatility? I always have had a mixed feeling about Noack, since it wasn't unheard of to have no measurable consumption back in the day when Noack would be in the 25% range.


Agreed we get all this crying about Noack but unless the vehicle is operated under severe conditions, ie in hot weather, loaded to max+ capacity, towing, etc few vehicles will experience BURN OFF... Which BTW which is different from oil usage from slightly worn rings, valve seals etc...

One thing about older vehicles(pre 1970s), generally they ran cooler thermostats, and had far less power accessories to operate... No doubt oil temps were less than today's average...
 
That bit about lower oil temperatures back then was almost certainly true. I'm sure there are exceptions on both sides of things, but generally speaking, the taxis had fairly reasonable oil temperatures, particularly in comparison to something like the G37. The F-150 doesn't exactly cook the oil, either. And of course, normal consumption problems, like rings, will exist independent of volatility.
 
I've changed to a different oil then suddenly have oil consumption. Usually after 3-4 more OCIs things get back to normal (no noticeable consumption)- or change back to what was working before.
 
This is exactly what I used to think. You only get burn off under conditions that are so extreme as to be unrealistic. Noack is good enough. Don't whinge people!

And then slowly but surely I started to change my mind...

Several years ago I made some 0W20 up in the lab and put it in my own car. Very nice oil. Full synthetic. About 11 ish Noack. Brilliant on fuel economy. Over the seven years I owned it, I got an average mileage of about 59.5 mpg!

One time I ran the oil out to 15,500 miles; high by US standards but not excessive by Euro standards. Lo and behold, 40% of the oil had 'disappeared'. Now I'm the world's most careful driver and the car hardly ever goes over 60mph. And it's only got a 1.0 litre engine so it never ever towed anything. And the UK climate, well it's hardly Death Valley is it? So where did the oil go and why?

The clue was the fuel dilution test I ran on the used oil - 8%! How did that get there? I started to dig around. I twigged that the Daihatsu engine was one if the first to use thin, low tension piston rings. Were these rings allowing fuel to get into the sump as a matter if course and was this fuel 'causing' the oil to exit the crankcase?

Then other stuff started to intrude and I put all oily questions aside for about five years while I went to sleep...

I can't remember when I first came across the stories about the Audi 2.0l TFSI. Stories of horrendously excessive oil consumption. But I do remember thinking that's odd. VAG oils are state-of-the-art synthetics. How can this be happening? I started to dig around. GDI engine. Reports of fuel dilution. Reports of people having rings replaced and NOT fixing the oil consumption problem (so NOT caused by worn rings). Valve seal replaced but problem persists (so NOT valve seals). Multiple reports of PCV valves being replaced but not curing the problem. Well publicised software updates which proved completely useless. Loads of video clips on YouTube of filthy intake systems, bad valve deposits, heavy cylinder deposits. It woke me up and I started to think about what might be the cause.

TBH, it was what Audi (belatedly) did to fix the problem that gave me the best clue as to what had happened. At HUGE expense, they started to dismantle engines to replace the rings, pistons AND the con-rods. I understood why they would change rings. I could also persuade myself why they might change pistons but why the con-rods?? Then I came up with a theory which may or may not be right but sort of fits the facts.

If the cause of the oil consumption problems was thin, low-tension rings then replacing just the rings wouldn't cure the problem. You would need to move to fatter, higher tension rings to achieve proper cylinder sealing. Of course the fatter rings might be too fat for the original piston grooves so you need new pistons and because thus would result in a slightly longer piston, you would need slightly shorter con-rods.

You extend the theory that thin, low tension rings aren't all they're cracked up to be. They let fuel and water get into the oil especially when the engine is cold. The evidence from my old Daitahsu was that you dont need extreme conditions or even GDI for this to occur.

The the interesting thing is what happens to this fuel and water when the engine warms up. Now as it happens, I'm a chemical engineer and I used to boil oil for a living. So although I'm very rusty, I sort of understand things like vapour pressure, multi-component vapour-liquid equlibrium, extractive and azotropic distillation. And then it struck me was that although engine oil is, at typical engine temperatures, almost completely non-volatile, if you mix it with a bit if petrol and water, then heat it up, through the vagaries of the vapour pressure laws, you can carry the most volatile part of the oil into the vapour phase. Once it's in the vapour phase it will pass right through the PCV valve and into the intake. As the intake system is cold, the oil will condense (which explains those dirty intake systems), hit the hot inlet valves (which explains the valve deposits) and into the cylinder where the recycled fuel and the oil it's 'carrying' is burnt and off it goes down the tail pipe.

And it's a repeating cycle. Drive home. Turn off engine. Engine gets cold. Start cold engine. Put fuel and water in oil. Drive. Engine heats up. Fuel, water and a tiny percentage of the oil are driven off. Stuff is routed to engine to be burned. Slowly but surely you deplete the sump. Death by ordinary driving...

And if all this is right, then one thing that will almost certainly exacerbate the problem is thin, high volatility engine oil which will exhibit a high vapour pressure. Hence my concern.

There's one other thing to say here. Petrol, even recycled petrol, burns no problem. Oil extracted from the sump burns badly. It probably has zero octane value. It probably burns to a mixture of soot and ash. Neither is good in a gasoline engine. This stuff will find it's way into the ring pack and down past the skirt. The tendency will be that this rubbish will foul the first and second groove and stick the oil ring. This will further degrade the efficiency of the ring pack so the entire process is self exacerbating. It's this that might explain why oil loss problems appear late on in the life of the car. I recently looked at a video on YouTube about a bloke with a dismantled Toyota engine where the piston were in a disgusting condition. Grooves were chocker with carbon, the oil ring was stuck fast and the drain holes behind oil ring were completely blocked. First thing I thought was this is exactly what would happen if you dump deposits 'over the top' so to speak.

All of the above is just my opinion and technical conjecture. Have probably said to much. Time for breakfast...
 
Hi Joe90-guy,

Welcome, its good to have you around. I've been enjoying hearing your view, both here and in the Euro Oil section with the HTHSv xW30 Vs xW40 thread.

I'm fairly new here myself, but I don't work in oil like you. However I do work in a lab (civy job) and spend many hours a week worrying about organics, vacuum, temperature and volatility. What you say rings true to me. Relatively small changes in temperature eg 50 deg C, can have a large effect on the amount and rate at which a light phase in a fairly stable organic mixture is mobilized.

I recall somebody else in another thread, was commenting about deposits in GDI engines, and according to their meta-analysis, changing the oil more frequently (a typical response to engine & oil problems) made the deposit problem worse. Their reasoning was that you were replenishing the light volatile components more frequently and thus making the problem worse.

My advice to the OP: Run a thicker oil !!
But, I'm Australian, so this is my advice to most problems.

Whenever I have had an engine that used oil, but didn't leak oil, I always run a thicker oil, and it always helps. I like to go up in both numbers, so if your starting oil is a 5W20, then I would prefer a 10W30 over a 5W30. I realize it's not that simple sometimes, you may live in a very cold climate, plus I consider a A5/B5 5W30 to be a lighter oil than a A3/B3 5W30.

I've been sipping the Kool-Aid on the HDEO as PCMO thread. Have you considered a mixed fleet 15W40 HDEO ?

BTW if your Honda isn't using enough oil, trade it for an old mitsubishi, that'll sort you out.
 
Originally Posted By: Joe90_guy
This is exactly what I used to think. You only get burn off under conditions that are so extreme as to be unrealistic. Noack is good enough. Don't whinge people!

And then slowly but surely I started to change my mind...

Several years ago I made some 0W20 up in the lab and put it in my own car. Very nice oil. Full synthetic. About 11 ish Noack. Brilliant on fuel economy. Over the seven years I owned it, I got an average mileage of about 59.5 mpg!

One time I ran the oil out to 15,500 miles; high by US standards but not excessive by Euro standards. Lo and behold, 40% of the oil had 'disappeared'. Now I'm the world's most careful driver and the car hardly ever goes over 60mph. And it's only got a 1.0 litre engine so it never ever towed anything. And the UK climate, well it's hardly Death Valley is it? So where did the oil go and why?

The clue was the fuel dilution test I ran on the used oil - 8%! How did that get there? I started to dig around. I twigged that the Daihatsu engine was one if the first to use thin, low tension piston rings. Were these rings allowing fuel to get into the sump as a matter if course and was this fuel 'causing' the oil to exit the crankcase?

Then other stuff started to intrude and I put all oily questions aside for about five years while I went to sleep...

I can't remember when I first came across the stories about the Audi 2.0l TFSI. Stories of horrendously excessive oil consumption. But I do remember thinking that's odd. VAG oils are state-of-the-art synthetics. How can this be happening? I started to dig around. GDI engine. Reports of fuel dilution. Reports of people having rings replaced and NOT fixing the oil consumption problem (so NOT caused by worn rings). Valve seal replaced but problem persists (so NOT valve seals). Multiple reports of PCV valves being replaced but not curing the problem. Well publicised software updates which proved completely useless. Loads of video clips on YouTube of filthy intake systems, bad valve deposits, heavy cylinder deposits. It woke me up and I started to think about what might be the cause.

TBH, it was what Audi (belatedly) did to fix the problem that gave me the best clue as to what had happened. At HUGE expense, they started to dismantle engines to replace the rings, pistons AND the con-rods. I understood why they would change rings. I could also persuade myself why they might change pistons but why the con-rods?? Then I came up with a theory which may or may not be right but sort of fits the facts.

If the cause of the oil consumption problems was thin, low-tension rings then replacing just the rings wouldn't cure the problem. You would need to move to fatter, higher tension rings to achieve proper cylinder sealing. Of course the fatter rings might be too fat for the original piston grooves so you need new pistons and because thus would result in a slightly longer piston, you would need slightly shorter con-rods.

You extend the theory that thin, low tension rings aren't all they're cracked up to be. They let fuel and water get into the oil especially when the engine is cold. The evidence from my old Daitahsu was that you dont need extreme conditions or even GDI for this to occur.

The the interesting thing is what happens to this fuel and water when the engine warms up. Now as it happens, I'm a chemical engineer and I used to boil oil for a living. So although I'm very rusty, I sort of understand things like vapour pressure, multi-component vapour-liquid equlibrium, extractive and azotropic distillation. And then it struck me was that although engine oil is, at typical engine temperatures, almost completely non-volatile, if you mix it with a bit if petrol and water, then heat it up, through the vagaries of the vapour pressure laws, you can carry the most volatile part of the oil into the vapour phase. Once it's in the vapour phase it will pass right through the PCV valve and into the intake. As the intake system is cold, the oil will condense (which explains those dirty intake systems), hit the hot inlet valves (which explains the valve deposits) and into the cylinder where the recycled fuel and the oil it's 'carrying' is burnt and off it goes down the tail pipe.

And it's a repeating cycle. Drive home. Turn off engine. Engine gets cold. Start cold engine. Put fuel and water in oil. Drive. Engine heats up. Fuel, water and a tiny percentage of the oil are driven off. Stuff is routed to engine to be burned. Slowly but surely you deplete the sump. Death by ordinary driving...

And if all this is right, then one thing that will almost certainly exacerbate the problem is thin, high volatility engine oil which will exhibit a high vapour pressure. Hence my concern.

There's one other thing to say here. Petrol, even recycled petrol, burns no problem. Oil extracted from the sump burns badly. It probably has zero octane value. It probably burns to a mixture of soot and ash. Neither is good in a gasoline engine. This stuff will find it's way into the ring pack and down past the skirt. The tendency will be that this rubbish will foul the first and second groove and stick the oil ring. This will further degrade the efficiency of the ring pack so the entire process is self exacerbating. It's this that might explain why oil loss problems appear late on in the life of the car. I recently looked at a video on YouTube about a bloke with a dismantled Toyota engine where the piston were in a disgusting condition. Grooves were chocker with carbon, the oil ring was stuck fast and the drain holes behind oil ring were completely blocked. First thing I thought was this is exactly what would happen if you dump deposits 'over the top' so to speak.

All of the above is just my opinion and technical conjecture. Have probably said to much. Time for breakfast...


Great read! It makes perfect sense too. Thanks for posting!
 
Originally Posted By: Joe90_guy
All of the above is just my opinion and technical conjecture. Have probably said to much. Time for breakfast...

Given you conjecture, what is your view of these catch cans we see added on by people?
 
Originally Posted By: shrooms
For some reason, high mileage Hondas consume oil. I'm in the same boat. But, what I have noticed is that, we need to go thicker. I'm using 10w30 Defy and it has slowed a lot. Still consumes, but much less.


Even though you have the best solution, the OP and everybody else in this thread will ignore your post. Don't get discouraged, there's one guy out there who agrees with you.
56.gif
 
Thanks for the supportive comments.

Yes, I agree with the chap that said changing oil too frequently might well be doing more harm than good because you are replenishing the volatives. Folks should be aware that while a US Group II 5W30 might have a Noack of 15% (already too high by my reckoning), it could easily contain something like Chevron 100R which has a published Noack of 26%.

The other thing I'd flag up is that oils tend to be at their most seal aggressive when they are fresh. Using them in the engine directionally neutralises this aggressiveness. Changing oils too quickly can hasten the degradation of any elastomers you have in your engine.
 
Regarding catch cans, I just happened to chance on this on the F150 forum...

http://www.f150ecoboost.net/forum/45-rx-...t-analysis.html

This guy has had the contents of his catch can analysed and to me, it looks very much like light base oil; just what I might expect to see if the engine oil was being 'distilled'.

If you want the best for your engine, then yes, a catch can would in my opinion be justified. As a closet tree-hugger, if thus was my decision, I might be a bit more conflicted!
 
My son has a 2003 Honda with the K24A4 engine. When purchased used, it had 150K miles on it appeared to burn about 1 qt every 2K miles. Never dripped or leaked any visible oil, it just 'consumed' it.

After several remedies including using MaxLife and a PCV replacement, I finally discovered that it had a small valve cover gasket leak on the firewall side, which drained directly onto the exhaust manifold. Oil was being burnt there, vaporizing most of the visual evidence. Since replacing the gasket, it is now at 180K miles and holding consumption at a respectable 1 qt/6K mile rate.
 
Last edited:
Joe90_guy, interesting as always.

A few thoughts:

You said that your excessive consumption was on an engine that was one of the first with low tension rings using your own 10w20.

But there are many here with vehicles with high mileage, using off the shelf xw20's with little or no measurable consumption. I myself have an xw20 vehicle that has had no consumption on xw20 and xw30 except after sustained higher speed highway driving in which instance the consumption occurred for both xw20 and xw30.

So maybe the low tension rings have improved since one of the first ones and they are truly able to deal with xw20?

I think your mechanism of why intake systems and combustion chambers get fouled is sound. I had a short tripped vehicle that had a clean as a whistle engine, but a disgusting air intake and terrible performance because of combustion chamber deposits.

Using the 3M fuel system cleaning kit and some Techron cleared that all up. And I suspect that using thinner oil or maybe even an engine flush after such fouling would also help since it is more able to clean deposits in the ring area.
 
Originally Posted By: Joe90_guy
If you want the best for your engine, then yes, a catch can would in my opinion be justified. As a closet tree-hugger, if thus was my decision, I might be a bit more conflicted!

That's good to know. I've always been of the opinion that they might be a nice thing to have, but far from necessary, or perhaps not even very helpful (i.e. like bypass filtration at 3,000 mile OCIs). But, I imagine for certain applications, it might be more valuable than in others, and perhaps the way things are going, there may be more value to them.
 
I had previously used Penzoil Platinum the prior two oil changes and had the oil consumption when I got a good deal on some Peak and used that oil. I had used Defy in the past as well without any consumption. But now am seeing the consumption going to the Defy again this OCI. Instead of pulling the valve cover and plugs I am planning to go back to PP and stick with it. See if it takes care of itself.
 
Originally Posted By: SR5
Hi Joe90-guy,

Welcome, its good to have you around. I've been enjoying hearing your view, both here and in the Euro Oil section with the HTHSv xW30 Vs xW40 thread.

I'm fairly new here myself, but I don't work in oil like you. However I do work in a lab (civy job) and spend many hours a week worrying about organics, vacuum, temperature and volatility. What you say rings true to me. Relatively small changes in temperature eg 50 deg C, can have a large effect on the amount and rate at which a light phase in a fairly stable organic mixture is mobilized.

I recall somebody else in another thread, was commenting about deposits in GDI engines, and according to their meta-analysis, changing the oil more frequently (a typical response to engine & oil problems) made the deposit problem worse. Their reasoning was that you were replenishing the light volatile components more frequently and thus making the problem worse.

My advice to the OP:Run a thicker oil !!
But, I'm Australian, so this is my advice to most problems.

Whenever I have had an engine that used oil, but didn't leak oil, I always run a thicker oil, and it always helps. I like to go up in both numbers, so if your starting oil is a 5W20, then I would prefer a 10W30 over a 5W30. I realize it's not that simple sometimes, you may live in a very cold climate, plus I consider a A5/B5 5W30 to be a lighter oil than a A3/B3 5W30.

I've been sipping the Kool-Aid on the HDEO as PCMO thread. Have you considered a mixed fleet 15W40 HDEO ?

BTW if your Honda isn't using enough oil, trade it for an old mitsubishi, that'll sort you out.



Changing to a thicker xxW-40 oil from OEM's xxW-30 , and occasionally to 20W-50 from xxW-

40 , appears to be 'the' way here in the tropics , to overcome engine oil consumption

problem ............ which works most the time .
smirk.gif


I think it'll work for OP.
 
Last edited:
Originally Posted By: Benito
Joe90_guy, interesting as always.

A few thoughts:

You said that your excessive consumption was on an engine that was one of the first with low tension rings using your own 10w20.

But there are many here with vehicles with high mileage, using off the shelf xw20's with little or no measurable consumption. I myself have an xw20 vehicle that has had no consumption on xw20 and xw30 except after sustained higher speed highway driving in which instance the consumption occurred for both xw20 and xw30.

So maybe the low tension rings have improved since one of the first ones and they are truly able to deal with xw20?

I think your mechanism of why intake systems and combustion chambers get fouled is sound. I had a short tripped vehicle that had a clean as a whistle engine, but a disgusting air intake and terrible performance because of combustion chamber deposits.

Using the 3M fuel system cleaning kit and some Techron cleared that all up. And I suspect that using thinner oil or maybe even an engine flush after such fouling would also help since it is more able to clean deposits in the ring area.


I agree. The vast majority of XW20 users have zero issues with consumption. For the most part, from what we've read in a recent Consumer Report article, it's the Euro vehicles that are burning oil per mile at an elevated rate. These vehicles use much 'stouter, thicker' oils. The theory is sound and makes sense here in the bitog vacuum but does not explain why this problem isn't more widespread. There have also been studies that say the complete opposite as it pertains to fresh vs used oils...

http://www.pecj.or.jp/japanese/overseas/conference/pdf/conference12-19.pdf

from 9/2013

Discussed:

Deposits in GDI vs PFI
IVD and CCD deposits
Effects of engine load on deposits
Effects of fuel and deposit formation
Effects of older oil vs fresh oil
Group II vs III vs IV regading fresh oil and used oil(very interesting page 15 of 20)
 
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