There's a gadzillion posts on BITOG of folks that have zero oil consumption in 4k, 5k, 8k, etc. Doesn't this mean that Noack is moot? Surely w/ the number of people reporting zero consumption, there are those who are using oils with 5% Noack rating, and those using oils with 8%, and up - but if you've got zero oil consumption - that means real world you've got 0% burn-off. So apparently oil doesn't burn off at reg. op temps - it gets consumed in other ways. So why are we concerned w/ Noack values? I ask you BITOG.
What's up with NOACK Volatility ??
- Thread starter ericthepig
- Start date
- Status
I think it may depend on the engine.
A cool "tight" engine would probably show little consumption and degredation due to Noack volatility.
A hot "loose" engine might be more susceptible to consumption and degredation.
A cool "tight" engine would probably show little consumption and degredation due to Noack volatility.
A hot "loose" engine might be more susceptible to consumption and degredation.
I understand "loose" engines causing consumption, but volatility is (theoretically) only a PCV issue - so that's basically apples to apples across different engines. (??)
When I first got my Ferrari 575 Maranello it used 1 qt. of Shell Helix Ultra in 500 miles. This is typical for that oil in Ferraris. It was a 5W-30 Shell oil. Most run 5W-40 in their cars with the same consumption. I switched to 0W-20 Mobil 1 and from that day onto the next 8,000 miles there was no oil consumption.
aehaas
aehaas
Also how the piston rings seal as well as the finish in the cyl walls, how the engine is driven,any leaky valve stem seals.
M1 0w20 is the "thinnest" oil I've personally read specs on (40deg and 100deg). I've pondered using M1 0w20 throughout the coming school year after reading your "Oil Basics" article - given my wife's multi-short-trip/day (like 5 or 6) habits. But I'm already getting 1qt/under 2k consumption on M1 5w30. I realize results will vary, but I've been emboldened a bit by your results.
That's true Steve_S - it's not just PCV.
Volatility is only one of the many factors in oil consumption rate. It can easily dominated by other factors. I measure it in my tests because it's easy to do and gives some hints of the oil's composition. It's good to have low volatility in general but it should not be a main factor in your decision for an oil.
JAG, but in these engines w/ "zero consumption" it can safely be said there are no other consumption factors. Thus (apparently) the only way out of those engines is thru evaporation, and apparently that's not happening either. And you know w/ that many people, the oils have Noacks across the spectrum.
I see what you are saying but there is always some amount of oil consumption. It can be so small that you can't tell on the dipstick but it's still there. There is also always evaporation of oil. If you look at PCV valves and the tubes involved in the oil vapor transport, they will always be wet from oil vapor. Maybe not much, but still wet. I don't think I answered your response completely so respond to this and I'll respond again.
I guess what my point is that if you have a certain oil and magically increase it's volatility by changing it's formulation without changing any other factor, it would cause slightly higher oil consumption if used in an engine that was run identically with both oils.
I don't have a scientific approach, only observations.
Lowest oil consumption on my cars is with Redline a low Noack % oil. Using Redline greatly reduced oil use in cars that had some oil consumption with other synthetics.
I've also had very low oil consumption with Mobil 1 0W-20 in our Honda Element.
I don't suppose I've ever truly had 'zero oil consumption' but it sure feels that way when the dipstick is always at the top, and once in a while I add a few ounces.
With lots of drivers and vehicles it is very comforting to feel that there is a lot of forgiveness with an engine/ oil combo and I don't have to worry obout someone running a quart low.
With GC 0W-30 I did notice some oil consumption and would find oil 1/2 quart low sometimes. This happened on some BMW and Subaru engines I use it in. So I always feel a bit more nervous and check the oil levels much more frquently.
There was no trend or linear consumption pattern, other than more consumption after an oil change and then it levels off. Also with subsequent oil changes with the same oil , consumption levles off.
A perfect linear oil consumption rate is so much easier to live with, then I know for example "3000 miles since I checked it? expect to find down .25 quart".
Whilke this is far from ideal, this is real world ...when cars are out of state I don't have lots of control over checking oil.
I think Noack numbers and PCV design explain part of the results and the rest is primarily determined by how well the oil keeps the rings clean and how the oil behaves in the ring pack.
Lowest oil consumption on my cars is with Redline a low Noack % oil. Using Redline greatly reduced oil use in cars that had some oil consumption with other synthetics.
I've also had very low oil consumption with Mobil 1 0W-20 in our Honda Element.
I don't suppose I've ever truly had 'zero oil consumption' but it sure feels that way when the dipstick is always at the top, and once in a while I add a few ounces.
With lots of drivers and vehicles it is very comforting to feel that there is a lot of forgiveness with an engine/ oil combo and I don't have to worry obout someone running a quart low.
With GC 0W-30 I did notice some oil consumption and would find oil 1/2 quart low sometimes. This happened on some BMW and Subaru engines I use it in. So I always feel a bit more nervous and check the oil levels much more frquently.
There was no trend or linear consumption pattern, other than more consumption after an oil change and then it levels off. Also with subsequent oil changes with the same oil , consumption levles off.
A perfect linear oil consumption rate is so much easier to live with, then I know for example "3000 miles since I checked it? expect to find down .25 quart".
Whilke this is far from ideal, this is real world ...when cars are out of state I don't have lots of control over checking oil.
I think Noack numbers and PCV design explain part of the results and the rest is primarily determined by how well the oil keeps the rings clean and how the oil behaves in the ring pack.
I guess that I've been very lucky then with both of my Honda vehicles. One was an '04 CR-V, the other is our '07 Pilot. Neither one has used any oil (visibly, anyway). The real lucky part is that being the fickle oil boutique guru of this forum. I've rarely used the same oil more than 2 OCI's in a row, and still no oil consumption, even with the different oils, all with different specifications and formulations of the additive packages.
Coincidence, or are Honda engines really that good. My personal opinion is both.
Coincidence, or are Honda engines really that good. My personal opinion is both.
"A cool "tight" engine would probably show little consumption and degredation due to Noack volatility.
A hot "loose" engine might be more susceptible to consumption and degredation. "
Dont you mean the other way around?? As engines heat up the pistons expand slightly because the molacules are moving around faster.. because they are warm. That would mean its tighter
A hot "loose" engine might be more susceptible to consumption and degredation. "
Dont you mean the other way around?? As engines heat up the pistons expand slightly because the molacules are moving around faster.. because they are warm. That would mean its tighter
Two vehicles I have with virtually no consumption are an '04 HD and an '04 Pontiac. Two others have varying amounts of consumption depending on what oil I use, a '96 HD and an '01 Chevrolet. The '96 HD seems to consume some no matter what oil I use, although the amount does vary depending on the oil. The '01 however can show near-zero consumption on certain oils or substantial consumption on other oils. The worst I saw on that vehicle was on an oil that had a NOACK of 8.9%, Amsoil XL 5W-30. ASL with its 7.1% was better and TSO, with its 8.5% was also better with nearly zero consumption. What does this prove? I don't know but the XL and TSO are nearly the same NOACK yet with one I have to add oil, probably 1qt or more every 5K, the other I add less than 1qt in 10K. Perhaps the formula+base stock AND the NOACK combined play more of a role together than either does separately. In my Pontiac 3800 or '04 HD I could probably use just about anything and never have to add oil between changes but in my Chevrolet 5.3L, I am more selective and take NOACK, formulation and base stock into account.
Lot's have people have reported their first fill with Amsoil resulted in oil consumption, and following fills less or none. Some have reasoned that some cleaning is going on, sending particles and soft sludge to the filter, opening up restricted areas, getting more oil to new macro and microscopic areas. I've never noticed any oil consumption in any of my vehicles between my maximum 12,000 mile/yearly oil changes with Amsoil. I think I've heard the same thing with Mobil 1 PAO.
Makes a lot of sense!
Some more interesting observations.
My wife drives a Dodge Caravan with the 3.8L v6. Her daily driving is the kind of stop'n go, short trip, variety. Typically showed 1 qt/3,000mi consumption on a steady diet of M1 5W30. Took it on a cross country trip with around 2,000 mi on the OCI and topped off to full with around 1/2 qt. Within 300 miles was a quart low. Added 1 qt M1 5W30. After another 3,000 miles of highway driving, the oil level hadn't dropped a bit.
My theory. Oil dilution due to fuel and/or water masked latent consumption. That is, as oil was consumed, some volume was made up by increasing fuel and water content. Long trip burned off the dilution and dropped the oil level to match--along with some burn-off. Once the dilution was dissipated, the steady high-speed driving, maintained the usual 3,000 mi/per quart consumption rate.
I wonder if some folks that observing zero consumption might really be experiencing "replacement" with dilution.
Roger...
My wife drives a Dodge Caravan with the 3.8L v6. Her daily driving is the kind of stop'n go, short trip, variety. Typically showed 1 qt/3,000mi consumption on a steady diet of M1 5W30. Took it on a cross country trip with around 2,000 mi on the OCI and topped off to full with around 1/2 qt. Within 300 miles was a quart low. Added 1 qt M1 5W30. After another 3,000 miles of highway driving, the oil level hadn't dropped a bit.
My theory. Oil dilution due to fuel and/or water masked latent consumption. That is, as oil was consumed, some volume was made up by increasing fuel and water content. Long trip burned off the dilution and dropped the oil level to match--along with some burn-off. Once the dilution was dissipated, the steady high-speed driving, maintained the usual 3,000 mi/per quart consumption rate.
I wonder if some folks that observing zero consumption might really be experiencing "replacement" with dilution.
Roger...
Triple_Se7en
$50 Site Donor 2024
Then there are cases where highway driving increases consumption. So many variables to consider.
- Status
Similar threads
