How come gas vehicle engines don't burn oil?

[LouNY]

Yep and non detergent oil you let the crude build up.

And many people thought that the HD on the "new" oil meant Heavy Duty instead of High Detergent.
Back then was when I first heard of dumping in a qt of ATF and running it for a half an hour before draining your oil.
Also some manufactures used to say only change the filter every other oil change.
Times and ideas do change over the years.

 

[Jstpssng]

And many people thought that the HD on the "new" oil meant Heavy Duty instead of High Detergent.
Back then was when I first heard of dumping in a qt of ATF and running it for a half an hour before draining your oil.
Also some manufactures used to say only change the filter every other oil change.
Times and ideas do change over the years.

You also changed the oil every 3000 miles. I remember the every other time oil filter, but everybody I knew changed it every time anyways.

I've had at least two older trucks which were belching smoke and semmingly on their last legs. Both times I dumped ATF in and they came out of it. One bitterly cold morning I stopped into the corner store and all of the old timers were talking about how hard their trucks turned over, yet mine didn't have any problem. Most likely the compression was so low that it didn't have a problem... About 8 months after that I was coming out of the woods after a day of hunting when the truck quit. I popped the hood and noticed lights shining under the truck. It wasn't an oncoming car though, my Cat was on fire.

 

[RalphVa]

Even diesels do not burn oil, e.g. the VW TDI and JD 2 series. Neither does the Isuzu.

The old 1983 240D Benz was designed to burn oil. Friends had one like ours and never checked the oil. Ended up ruining their engine.

Ralph

 

[goeduck]

Dyno lab mech engineer here. We run a lot of oil consumption tests.

All engines burn some oil. No set of piston rings is able to scrape 100% of the oil of the cylinder walls on the downstroke. You wouldn't really want that, anyway. Then how would the rings be well lubricated for the return upstroke? Oil consumption is a known engine design consideration. Most OEs target around 10,000 miles per quart nowadays.

So why don't you notice that on the dipstick? Well, either you're not paying real close attention, most likely, and it's still in the "normal range" on the stick. No problem. More likely, some of the oil that has been burned away has been replaced in volume with combustion byproducts (soot and un-burned or partially burned hydrocarbons), and especially in direct-injected turbocharged engines, raw gasoline. It sneaks past the rings down into the crankcase from cylinder pressure, or gets scraped down if left on the cylinder walls during the power stroke. We call this "fuel dilution", and it can get as high as ~10%. Meaning, 10% of the oil you drain out during a change is actually mixed-in gasoline. Diesel engines do this also.

All engines burn oil. They have to. If you don't notice it, or it seems like zero consumption, great!

Great write up. I often thought the same thing but never had any knowledge to back it up.

 

[sixdogs]

And many people thought that the HD on the "new" oil meant Heavy Duty instead of High Detergent.
Back then was when I first heard of dumping in a qt of ATF and running it for a half an hour before draining your oil.
Also some manufactures used to say only change the filter every other oil change.
Times and ideas do change over the years.

I n the 1950's I think an oil change was at 1,000 miles. Then it was 3,000, then 5,000 mile synthetic Mobil 1 that later became 10,000 miles. Now, there's 20,000 mile extended interval synthetic oil and 400 hour or more oil change intervals for some farm tractors using synthetic oil. I'll bet we see something like 50,000 mile oil change intervals in our lifetime.

 

[sixdogs]

Dyno lab mech engineer here. We run a lot of oil consumption tests.

All engines burn some oil. No set of piston rings is able to scrape 100% of the oil of the cylinder walls on the downstroke. You wouldn't really want that, anyway. Then how would the rings be well lubricated for the return upstroke? Oil consumption is a known engine design consideration. Most OEs target around 10,000 miles per quart nowadays.

So why don't you notice that on the dipstick? Well, either you're not paying real close attention, most likely, and it's still in the "normal range" on the stick. No problem. More likely, some of the oil that has been burned away has been replaced in volume with combustion byproducts (soot and un-burned or partially burned hydrocarbons), and especially in direct-injected turbocharged engines, raw gasoline. It sneaks past the rings down into the crankcase from cylinder pressure, or gets scraped down if left on the cylinder walls during the power stroke. We call this "fuel dilution", and it can get as high as ~10%. Meaning, 10% of the oil you drain out during a change is actually mixed-in gasoline. Diesel engines do this also.

All engines burn oil. They have to. If you don't notice it, or it seems like zero consumption, great!

That sure makes sense.

 

[LouNY]

I n the 1950's I think an oil change was at 1,000 miles. Then it was 3,000, then 5,000 mile synthetic Mobil 1 that later became 10,000 miles. Now, there's 20,000 mile extended interval synthetic oil and 400 hour or more oil change intervals for some farm tractors using synthetic oil. I'll bet we see something like 50,000 mile oil change intervals in our lifetime.

I wouldn't be surprised but I know that I'll never go that long my RAM has the monitor on it and it doesn't look like it would have gotten to the 10,000 mile mark,
but I have only let it get to 0% life one time I usualy change at 5-6000 some times even sooner depending on the weather and my planned driving.
Heck I still treat the factory fill as breakin oil and dump it at 500 miles or so.

 

[California]

I current own four Fords. The oldest being a 1993 F150 up to a 2016. None of them have shown low of oil on the dipstick.

Likewise, my 2005 Ford Focus Wagon. 150k miles now, and its still full or real close to it on the stick, and nearly clean in color, at the 10,000 mile oil changes I learned were specified for this engine in Europe. Much of my miles are the 100 miles each way between home and ranch at near constant speed, a 'light use' application.

For several cars over the last 30 years I've followed the rule of change the oil when it's down a quart, so intervals of 4 to 9 k miles. All have run until sold at over 125k miles without much increase in consumption. I use semi-synthetic oil, Motorcraft, Castrol etc. I believe in the theory that most engine wear occurs at a cold start, not on the highway.

Modern cars are completely different than what most of us learned on. One example is much better air cleaners which reduce cylinder wear. And of course, far better oil is specified today. I think oil-related engine failure is mostly a thing of the past, now.

 

[Molalla1]

And many people thought that the HD on the "new" oil meant Heavy Duty instead of High Detergent.
Back then was when I first heard of dumping in a qt of ATF and running it for a half an hour before draining your oil.
Also some manufactures used to say only change the filter every other oil change.
Times and ideas do change over the years.

:thumbsup: . . .

 

[5030]

That's exactly right. If it's bothering you sixdogs you can make it start using oil by driving around the block a few time between draining and refilling oil next time you change oil.

.................. If it makes it that far..............