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What does oil break down into that is not slippery?

I made a bet with my boss in 1984 (when I was a young mechanic, not a chemist), and my dad later that day - I will never change my oil (No, not the filter either) again, just add when needed, and not suffer any oil related issues. In that time I’ve driven several vehicles (with and without fuel injection, but not diesels) 100,000’s of miles, most of the vehicles had nearly 100k when by the time I got them, and I drove some way past 200k. One was a retired Public Service(the old electric company around here) van that probably had the odometer roll twice before I got it at an auction and used it as my construction van during the 90’s for 70-80k miles. The tranny was rough when I got it and nearly dead when I donated it for scrap, no radio, heater, windshield wipers, interior lights, seat fabric, muffler, and much more in the NOT category, but the motor always started and ran strong, it passed yearly emissions testing(so did all my other cars). A few years ago I bought a 2003 Dodge Caravan with ~70k, it now has over 100k, although it’s not that many miles, it’s the only car I have that has MPG readout and it says I’m still getting about 19mpg, the same as when I bought it.

So I would say that I have yet to lose that bet, the only mechanical problems I’ve suffered have been outside the engine, usually something attached to a spinning belt, or wheel. Neither my boss or dad ever paid up (I forgot what is was), they’re gone now so I can’t continue to rub it in. In defending my reasoning to others over the years I extended the bet to many of my things that have oil, like my air compressors, lawn mowers and generators. I have an air compressor holding ~150 psi that has been turning on at least a couple dozen times a day for the last 22 years, no oil change, no problems - ever.

Do I think that all the guys with the extensive explanations the perils to be had by those that don’t change their oil (with the good stuff of course) are wrong about what happens to mechanical parts? No, well maybe. Am I just the luckiest guy in the world? Or was I right in 1984 when I asked - what does oil that has been in the ground for millions of years at high heat and pressure, oil that was refined by boiling it at temperatures way higher than will ever be seen in an engine, what does this oil break down into? I have never seen oil “break down” into something that is not slippery, so why is changing oil any kind of insurance?. Now, if you drive a race car (high rpm and loads on the motor parts) or if your engine gets overheated, or something like coolant gets in the oil, then there might be problems, and I suppose I wouldn’t apply this to things like a gearbox on a windmill until I had some experience with that sort of thing . So yes, I’m sure it’s important to change your oil in your car, if you are planning on keeping all the rest of the parts for eternity, otherwise my experience says your just wasting your/their money, boss;)

It’s been almost 30 years and although I have never seen it, and I’m still not a chemist, I’m still wondering, and asking - what should I expect my oil to “break down” into that is not slippery?

As far as changing oil for sake of the filter and the bits of metal that ground off when a cold engine starts, I say leave the bits in there, after the engine warms up they will be re-deposited where needed, that’s just like the theory behind engine compression boosting products, isn’t it? Some of those products have suspended metal bits that are small enough to flow through the filter, but that fills scratches in the cylinder walls, don’t they? It seems like oil that has been flowing around for a while would have a give-and-take type relationship with the engine, and changing the oil is removing all the bits that are like salve for the motor, putting in an aggressive astringent that soaks up a whole new layer of engine bits that are flushed away a few thousand miles later. That’s why even well maintained motors start to loose compression after 100-150k or so, maybe it’s worse the more you change? This is all just my theory, I’m still testing it (not the changing more part). But really, why am I not having any problems?

Well Hobie, at one point you ask “Am I just the luckiest guy in the world?” and I think the answer has to be YES! (Does anyone remember Gladstone Gander?)

Under normal operating conditions, motor oil eventually turns into sludge, some kind of gel-like stuff that clogs passages and filter screens. A few years back, Toyota had major recalls when its engines tended to sludge up and get ruined.

I congratulate you for a successful experiment, however ill-advised. I wonder, though, if we have all of the facts. Did your engines burn or leak so much oil that you had to add a fresh quart every week or so? That action would tend to reduce or eliminate the problems that normally arise with refusing to change one’s oil.

Well, keep on doing things your own way. One day you WILL get bit, that’s almost certain, but I don’t think you will return here with your report. No fun to eat crow.

Also what about the contaminates that get in the oil during use? If you don’t change it ……

Your understanding of motor oil and its functions is so rudimentary, that there’s not much point in going on too much about it. Spend a bunch of time learning about motor oil before “theorizing.” For education by internet, this site is considered one of the best of the web:

If you don’t come across enough of it there do some searches for photos of engine sludge.

I don’t think anyone will doubt that you can completely abuse machinery and still have it work for a long time. So the fact that you have been abusing machinery and it hasn’t imploded on you doesn’t say much.

But, hey. Its your machinery. Do with it as you will. Most people don’t choose to just drive any piece of machinery they own into the ground. But you can if you want to.

I worked in a gas station in the late 60’s/early 70’s and we had a customer that also never changed the oil in any of his cars. He changed the filter every 25K miles and kept all his cars for 100K miles. He too never had a problem with any of his cars.

Engines today place more demands on an oil, so if you’re getting away with your no-change habit on a current vintage engine, I’m impressed with your luck. Also, there are a handful of engines produced today with a flawed weakness that causes the oil to turn to sludge prematurely.

It’s easier to get someone to change their religion than it is to get them to change their thinking on oil change intervals.

If you ever sell any of your cars, I hope you disclose this neglect to the buyer. It would be unethical to do otherwise.

I would agree with the OP that oil doesn’t lose its “slipperiness”. However, oil does pick up contaminants. Years ago, in his book “What You Should Know About Cars”, Tom McCahill did not like detergent motor oils because he didn’t want the particles that the detergent oils hold in suspension being constantly whipped through the bearings on his engines. He thought a non-detergent oil was much better because the particales in the oil dropped to the bottom of the oil pan and would build up a crust just like the burned tobacco does in a good pipe. Now I disagree with “Uncle Tom” on not using detergent oil, but I agree that the particles are held in suspension and after time, the filter can’t remove all these particles. Therefore, I would rather not have these particles going through my engine bearings. Also, there is some sulpher in gasoline. After compustion, the sulfer combines with the water and oxygen to form sulphuric acid which is very corrosive. I would rather not have this acid in a high concentration in my engine oil.
I did once purchase a used 1955 Pontiac that was probably treated by someone such as the OP. The dealer from whom I bought the car had overhauled the engine before he sold it to me. However, I had a constant problem with sludge getting into the oil passages on the studs that held the rocker arms The rocker arms would then run dry and chirp. The oil filter on the 1955 Pontiac was an option, and the one I bought was not equipped with an oil filter. I did buy the oil filter assembly at a salvage yard and install it. However, I never completely got rid of the problem with that engine.
I used to purchase re-refined oil for my 1947 Pontiac that used a quart of oil every 250-300 miles. I think it was about a dime a quart in bulk. However, I did change the oil about every 2000 miles in order to protect my $75 purchase that made the 350 mile trip from my home to graduate school and was my only transportation.

And I can show you thousands of smokers who’ve never had a problem and show no signs of ever having a problem…That doesn’t mean it’s NOT harmful.

Your cars may not show signs of damage…but I’ll bet that if you tear apart those engines they’ll show signs a major wear.

Motor oil does not break down or “wear out”…It gets contaminated by combustion products that blow by the rings and into the crankcase, slowly contaminating the oil…When the oil can absorb no more, the contaminants form “sludge” on the inside surfaces of the engine. If this sludge forms on a critical part, say the oil pump pick-up screen, oil pressure is lost and engine destruction soon follows…Not mentioned was the amount of fresh oil added to these engines of yours, mostly old beaters by the looks of it…If you are adding a quart every 1000 miles, then you are in effect changing your oil every 5000 miles, just like the book says…Except you are doing it one quart at a time…

Since there is no combustion in an air compressor, and they operate at very low RPM, their lubricating oil will last a very long time…

@MikeInNH beat me to it.
For every George Burns (smoked cigars and lived to 100) there are many Ulysses Grants, Babe Ruths and Sigmund Freuds (disfigured by mouth & throat cancers).

Does anyone other than me smell a troll here?

I tend to agree with doubleclutch.

Another reason to buy new instead of used. Never know what looney toon has been a previous owner.

I don’t see the OP trying to sell anything, so my feeling is that it’s just someone trying to open an interesting discussion. And I think he asks a good question. There are many people out there that really don;t see the need to change their oil regularly. It’s a good subject to address, even though we’ve done so before.

Cig’s link to Bobistheoilguy is an excellent place to start the discussion. Others here have alluded to oil becoming contaminated and diluted by blowby as well as particulants…as well as anything that happens to be in the blowby like traces of sulpher.

I’ll add one more point: I’d give anthing to see what a filter must look like after 100,000 miles. It must look like a canister of mud. How, pray tell, can the oil circulate through a canister of mud? Praise be for bypass valves!

To the OP: yes, you absolutely must be the luckiest guy in the world. But I’d hate to be the poor fella that buys your car when you’re done with it. He’ll be one UNlucky guy.

How much oil do your cars average using by the time they have 100K, 200K, 300K miles? I own an '88 Ford Escort with a 1.9L 4 cylinder and has had regular oil changes. It had between 250 and 300K miles before it started using enough that it had to have oil added between changes. Yes it has progressed into using more oil since, but the car is now 24 years old has 518,600 miles and has never had the head off it. It’s now using about a quart every 800-1K miles. I checked the compression about a year ago, with over half a million miles the compression readings were in the 145-155 psi range. You also said in '84 when you were a young mechanic you made this bet. I’m doubting you continued to pursue a career as a mechanic, otherwise you’d have likely seen multiple cases of the damage that can be done to an engine with no or long drain intervals. Even my '88 Escort which has averaged an oil change about every 5K miles is now beginning to create some problems with oil sludge. I have two other cars that have about 200K miles each on them that use about 1 quart of oil between changes. Two cars with about 125K miles one uses about 1/2 quart between changes the other one doesn’t use any. One car with 90K miles that is still sitting on full when the time for an oil change comes around. If you look through the oil fill in the valve cover at the head and valve train in the 200K, 125K, and 90K mile cars they’re all still clean with no build up at all and if the oil was washed off of them I’d literally eat off of them. To me a $15-$20 oil change every 5K miles is pretty cheap insurance for a multi thousand dollar piece of machinery. Back when the price of oil started going up I bought about 30 cases of oil for $1 a quart or less each and stored it in my garage and I’ve bought filters at store closeouts, flea markets and yard sales for $1 each or less, so my oil changes still average costing me about $5 each. It would take many, many oil changes to pay for the cost of one new engine.

HobieTcat, Fordman has posed an interesting question. Can you tell us how much oil your cars typically use when they get to 100,000, 200,000, and 300,000 miles? That might give us some data we can work with, some data we can compare with our own, to ascertain how different your usage might be.

While I fully realize that volumetric usage is only a part of the picture, at least it’d be something to ponder.

Many years ago, and still even today I guess, people installed an aftermarket oil filter, a by-pass type, very low flow rate, that used a roll of toilet paper as the filtering medium. The Frantz Oil Cleaner it was called. Oil was forced through the roll of paper end to end…And yes, the oil stayed a nice amber color for many, many miles…The roll of paper was able to remove or absorb virtually all the blowby residue from the engine oil, virtually eliminating the need to change the oil…

When it came time to change the filter element, that was a dirty, tricky job, extracting the saturated roll of paper and fitting a new one…(arguments raged over which brand of toilet paper was best…) How to dispose of that nasty, contaminated, dripping roll of paper was never mentioned…You don’t want to even think about where those ended up…

Thanks for the input guys! Although I was not expecting the personal attacks, after all, I’m not telling you what you should do, I’m asking why I have not experienced the perils that virtually everyone has said that I should over the years. It doesn’t look like I’m getting too far trying to have an intelligent discussion here, The search goes on. But to be clear, I have put my money where my mouth is for the past 30 years and have been derided by the best of them “saying” how stupid and irresponsible I am, but no one has been able to “show” me anything that makes me second guess myself. And I don’t think my point was received by all the commentators.

I agree that moving parts wear and oil is essential to reduce wear, but what I am asking is what could I (people) look for to determine that oil has failed? And how is that possible?
As I said before - I think everyone agrees that even the best maintained engine will wear and start to lose compression and get a little sloppy around 150-200k and most people don’t keep their cars much longer than that because of all the other things that start to fail and wear, like paint, so I say if my car is going to end up in scrap yard anyway and I’m thinking about it in a cost/benefit way, wouldn’t it be ok if the motor is not perfect when the rest of the car is mostly dead anyway? But that’s just me a little off topic.

My original question was about what oil, that has been slippery for millions of years in the ground at high temps and pressures, and faced very harsh conditions during refining, breaks down into in the relatively short easy life in my car? From the responses I think I’m sticking with my bet, it does not appear that anyone has “seen” an engine fail because of oil that has lost is lubricating ability, they just “know” that it would. People have said in past discussions that losing a bearing or rod is because of bad oil, but that doesn’t make sense, if the oil stopped lubricating the damage would be almost identical to an engine that has run out of oil - seized solid with many moving parts that are damaged, not just one bearing or one rod and the others are fine. In the many years I have been pitching my theory I have yet, including the guys I made the bet with, to find someone say they have seen an engine that has seized and it still had oil in it. And I have yet to see any motor oils that have gelled, or changed their viscosity or lubricating ability in any meaningful way, no matter what the conditions.

I checked out the link to and found lots of information that seems to support my theory, yes engine parts wear, but not as fast as they rest of the car. Bob seems to have some pretty sophisticated testing equipment too, and I understand the info about contaminants getting in the oil, but again, do they make the oil so that it does not lubricate? Maybe these ‘contaminants’ are what products like Restore and Slick 50 have in them already - particles that fit through the filter and get deposited on metal parts to fill scratches, anyone want to address that one? BTW, most of the data on his site seems to be for diesel engines, which I’m not claiming anything on, I’m just talking about gas engines that are not subject to harsh conditions like red-line rpms all the time, like a race car or something.

And just a specific response from me on comments: As far as making an analogy to the risks of getting cancer from smoking and what I am talking about, it doesn’t seem to apply because we know that statistically smoking will cause cancer at some average rate. I think my theory makes the same point - for years people in the industry claimed that smoking did not cause cancer, but they were easily proven wrong when real data, not anecdotal like “I smoked for years and never got sick” was collected. I’m saying that the data in my case says that companies recommending oil changes are getting people to change their oil wwaayyyy more often than is necessary. Although I too am using anecdotal evidence, that’s all I have because I am searching for at least one real data point that shows that motor oil will lose it’s slipperiness to the point of premature failure and have not found one. I have been trying for 30 years to establish that data point myself. So, for me, when I look at real data it makes me want to stop smoking and stop changing my oil.

BTW, what is a troll?

I forgot to answer the question about my oil usage. Cars have been different of course, but I would say that I add a quart to my 2003 Caravan every 8-10K, the other cars didn’t use much oil either.
Also, I sold a '93 Bonneville with 230k (I bought it at 120k) to my neighbor for $100 a few years ago, he still drives it to work every day. None of the power stuff like seats, mirrors, fans or windows work and the paint is mostly gone on the top surfaces, last I talked to him he said the engine and tranny were great! I don’t know if he changed the oil, but I told him I didn’t.

It is my understanding that the oil does not wear out, but all the contaminants and grit in the oil end up working like sandpaper in an engine, the most common wear point being the piston rings. The wear on the piston rings allows a burning oil situation. When you burn oil you have to replace it. The first car I had before shop class I was of the just add more oil. The engine ate more oil and more as time went on. In shop class we had the chance to rebuild engines, and the major reason for needing a rebuild was a lack of oil changes. Sure your experiment worked for you, amazing to me, but in my general view if you want things to last, you take care of them and neglecting oil changes is not taking care of them.