5,000 miles....7,500 miles...10,000 miles....

March 7, 2013 8:09 AM

How is it that newer model cars are able to go increasingly longer distances and periods of time without regularly scheduled service?

I have a 2011 Volvo XC60. The first several regularly scheduled services are 7,500 miles (or 10 months, whichever is sooner) apart. When I told the dealer that seemed awesome, he said "the newest models are 10,000 mile increments". What are the actual technical improvements that allow for such long periods between service? I think it has something to do with synthetic motor oil but I am curious to know specifically how this all works and whether there is any theoretical limit. Will 12,500 miles be next?

posted by Dansaman to technology (15 answers total)

There's an explanation in "Stop Changing Your Oil" on Edmunds.com. Some points from the article:

• 'Improved "robustness" of today's oils, with their ability to protect engines from wear and heat and still deliver good fuel economy with low emissions'
• 'Tighter tolerances (the gap between metal moving parts) of modern engines'
• 'The introduction of oil life monitoring systems, which notify the driver when an oil change is required and are based on the way the car is driven and the conditions it encounters'

The article notes that there cars made by Porsche only need oil changes every 20,000 miles so it stands to reason that regular consumer models only needing changes every 12,500 miles are an attainable goal.
posted by bcwinters at 8:15 AM on March 7 [1 favorite]

Technology improvements, of which synthetic motor oil may be one, have lead to more reliable cars over time. (For the most part. There are always outliers in that general improvement trend, like the Ford Pinto, etc.)
posted by dfriedman at 8:16 AM on March 7

While the initial comments are most certainly true as a general trend, we must also take into account warranty repair costs, free maintenance costs and statistics: if you are a company that starts out at 7,500-mile increments and you're not incurring high warranty repair costs -- and you're offering free scheduled maintenance during the warranty period, which Volvo is certainly doing right now -- then you might try 10,000-mile increments during the next model year.

I own an in-warranty Volvo with free maintenance, and have received this advice from an independent specializing in Volvos: change my oil every 5,000, because the 7,500-mile intervals are leading to high oil consumption in as little at 60,000 miles (out of warranty, of course), and the 10,000-mile intervals will likely be worse. I disregarded this advice, and now at 35,000 miles, I'm consuming a quart of oil at about 4,000 miles, which was not the case previously.

So yes, the technology of oil and assembly tolerances are getting better, but there's also statistical analysis going on, and if a company wants to offer free maintenance and lower up-front costs, and (perhaps) doesn't care as much about long-term reliability (*cough*GeelyownershipofVolvo*cough*), that's a contributing factor as well.
posted by davejay at 8:27 AM on March 7 [1 favorite]

It is mostly the oil itself. Synthetic oil with the proper detergents and other additives is just much, much better than what we used to use.

This is not really all that new: I have 2000 diesel Jetta with a 10K mile oil change interval. Big rig trucks have been running even longer (like 30K, 50K) oil change intervals for years. They can also take advantage of oil testing that can determine if/when the oil needs to be changed (this makes sense when your oil change costs hundreds, not so much when it costs tens).
posted by ssg at 8:28 AM on March 7

The article notes that there cars made by Porsche only need oil changes every 20,000 miles so it stands to reason that regular consumer models only needing changes every 12,500 miles are an attainable goal.

I couldn't tell you why it is different for the US but in the UK this is already a thing, and has been for some time. My 2005 Ford Focus had a 12,500 mile scheduled service period, and that was not considered unusual. My girlfriend's new Fiat 500 has a service schedule which is 18,000 miles or one year, whichever is sooner.
posted by jonnyploy at 9:29 AM on March 7 [1 favorite]

It is oils, and it is the reliability of modern cars. There is also a school of thought that manufacturers have responded to pressure from fleet owners to reduce service intervals (which also, of course, reduces maintenance costs) - at the expense of higher running costs later down the line.

I have no idea if this is true, but for fleet and personal owners, longer service intervals have appeal because they sound like cost savings. If manufacturers reduce service intervals they get accused of milking customers for unnecessary oil changes. If they increase them, they get accused of increasing the risk of problems when the car goes out of warranty.

Certainly, however, it is true that manufacturers do believe that cars are basically pretty reliable in their first five years, which is why a) Korean manufacturers offer a 7 year warranty and b) manufacturers like Mini and Audi (and others) sell prepaid service packs.

But as a counterpoint, Peugeot and Citroen are actually now reducing service intervals in the UK. Both of these brands in the PSA group have middling reputations for reliability so there's that.
posted by MuffinMan at 9:45 AM on March 7

Just chiming in to note that while synthetic oils and engine technology are improving every day, its also likely more than a coincidence that when most manufacturers started offering free maintenance, the intervals between oil changes also increased.
posted by teriyaki_tornado at 10:06 AM on March 7

I can't comment with any knowledge on the engine side of things, but I can talk about the oil.

Oils have two problems in engines: they can pick-up metal particles from engine wear and they can breakdown chemically.

Metal wear particles are bad because they act like a wet abrasive on the engine parts and can scour surfaces, producing more metal particles. The feedback loop can lead to catastrophic failure: a seized engine or gearbox. Metal particles are removed by oil filters and magnetic scavengers.

Oil breakdown happens because of heat-induced reactions in the oil itself. The most common of these are what's called a free-radical breakdown. A single hydrogen gets knocked off the carbon-hydrogen backbone producing a highly-reactive "free radical" intermediate. Heat and/or the presence of oxygen are common causes of radical formation.

Radical formation leads to the joining of oil molecules, polymerization of the oil. Oil polymers cause viscosity changes in the oil (usually raising it), which makes the lube less effective. Polymers further bond to the engine surfaces forming varnishes, which also reduces lubrication.

Lube oils are composed of long chains of carbon atoms decorated with hydrogen atoms (hydrocarbons). These free radicals form most easily at joints, branched chains where two or even three chains meet. These branched alkane compounds are naturally present in refined lubricating oil. Natural oils thus have built-in weak points for thermal and oxidative degradation.

Synthetic lubes are engineered to remove those branching-chain weak points. This is one of the major advantages of synthetic lubes (others include engineered chain length to control precise viscosity and temperature characteristics, but those are less important for oil lifetime). Removing the free-radical stabilizing "isoprenoids" can greatly increase the lubricant lifetime. Synthetic lubes are engineered mixtures of mostly straight-chains hydrocarbons. These are made from natural lubes by passing though a catalytic upgrading process.

Finally, anti-oxidants are added to the oil to scavenge those free radicals which do form. These are non-hydrocarbon compounds, added as a last line of defense. They have to be heat-stable so they don't break down on their own (and cause problems), but more reactive than the hydrocarbon compounds themselves. Antioxidants are the police of the lube oil: any free radicals which form get scooped up by the antioxidant brigades, and so cannot spread their subversive breakdown to the other straight alkanes.

So those are three of the technologies used to improve engine lube life: active removal of wear metal particles, engineering the hydrocarbons in the lube to remove break-down weak points, and adding anti-oxidant chemicals to the lube to stop break-down reactions when they do occur. There have been large advances in all three of these technologies in the past few decades. In combination, these changes have really extended the lifetime of hot lube oils.
posted by bonehead at 11:06 AM on March 7 [8 favorites]

I had a previously on this ages ago, noting the difference between service intervals for the same model car in Europe vs the US; there's a more recent one too.

On-board diagnostics surely have a role in this, because they can turn scheduled maintenance into problem-driven maintenance, and provide significantly more data to manufacturers on what needs doing when.
posted by holgate at 11:42 AM on March 7

This also represents a clear decision by the car maker to invest in increasing the maintenance interval in order to lower the car operators total life cost.
The car maker invests research time, money, data collection (as holgate described) in order to give you an additional reason to choose this make/model.
Often the real service intervals are not exactly known and the manufacturers take the existing (used forever) values without checking them. Now, they are all looking for new 'features' to sell and this is one of them and they are investing here and looking more closely.
As MuffinMan wrote - this is very important for fleet owners who will compare different makes/models with a total cost of ownership overview. Longer maintenance intervals mean not only less maintenance, but also more time in operation earning revenue.
posted by jazh at 12:16 PM on March 7

It's also an industry that has had 100 years of continual improvement. They have a lot of things figured out. Bearings, materials, manufacturing. They figured out how to make hoses that last the lifetime of the car, bearings that don't need to be greased and can go 200,000 miles, spark plugs that don't wear out for 100,000 miles, lightbulbs that last years, electronic ignitions that don't have distributors, points, condensers and so forth. Fuel injection is a big one: the more precisely you can control the fuel, the cleaner the engine stays. Now with things like electric power steering, direct injection and throttle-by-wire, efficiencies and wear items are all but eliminated.

And not just oils, but also fuels. Fuel is remarkably cleaner than it was even 10 years ago. Do you remember when Amoco Ultimate came out and it was touted as so clean that it was clear? I haven't seen non-clear gasoline in a long time now. That's a lot of weird gums and varnishes that aren't clogging up your engine.
posted by gjc at 7:49 PM on March 7

I had a '74 Plymouth Duster (318 V8) that I got in ~1992 with the odometer reading 75,000 (I suspect it was 175K or 275K, but who knows), I put 100,000 miles on it and only changed the oil once. I only paid $200 for it, so not too many oil changes would have cost more than the car. Now that I think about it, I haven't changed the oil in my daily driver (a '68 Pontiac Tempest) in about 5 years. I guess I should do that.
posted by 445supermag at 9:01 PM on March 7

I put 100,000 miles on it and only changed the oil once.

What?
posted by ovvl at 9:12 PM on March 7

What?
posted by ovvl

It did leak some, so I would add more oil when the oil pressure light came on, so some new oil would enter the system.
posted by 445supermag at 10:02 PM on March 7

I asked someone I know who knows a lot about cars, and has worked in auto parts, about this. He said there are a couple of major factors. First, engines burn cleaner these days, so they produce fewer products of combustion that might get into the oil. When those combusion products get into the oil, they render the oil corrosive to the engine, which is why you need to change the oil. The second factor is the much tighter tolerances of engine construction. The seals in the cylinder are much tighter, preventing the products of combustion from getting into the oil as the piston moves up and down the cylcinder.
posted by Dasein at 8:39 AM on March 18