[dotancohen]

Thanks, I updated the post. I had no idea that oil changes are now once every two years. On the wife's Subaru I still change the oil every six months, and I remember when the standard was actually every three months. She puts about 10 km on the car during those six months, we live in a hilltop village half an hour drive from a city.

[thaeli]

Time based oil changes (as a backup to mileage) in gasoline vehicles are mostly to address oil contamination from the engine not getting hot enough to boil off fuel and combustion byproducts in the oil. It's a rough heuristic for drive type - more advanced oil life monitors know the actual drive cycles an engine is seeing and will adjust appropriately, but for a basic time-and/or-mileage schedule, it's more about picking some interval that gets the oil changed before the additive package is destroyed by combustion acids. If the car is driven only short distances and never gets a chance to fully warm up, six months is probably a reasonable interval. If it gets a monthly spin on the highway for an hour, two years is probably fine. Ideally, you'd be measuring total base and total acid levels and calculating change points based on that; this is common practice for large truck engines but for a gasoline car engine, an oil change can be cheaper than the lab tests. (I'm still in favor of having oil testing done on at least some changes, it's basically "routine bloodwork" for your car and can detect many problems early.)

Another upshot of this is that with rarely driven vehicles, you might as well use the cheapest oil which meets appropriate specs, because your oil changes are driven by additive depletion and oil contamination rather than breakdown of the oil itself.

[dotancohen]

  > Another upshot of this is that with rarely driven vehicles, you might as well use
  > the cheapest oil which meets appropriate specs, because your oil changes are driven
  > by additive depletion and oil contamination rather than breakdown of the oil itself.

The Ferrari gets the cheap stuff, the Kia gets the good stuff. I love how some things are so unintuitive.

I just ordered an oil testing kit from Blackstone. Thank you for the idea.

[PinguTS]

What? Oil change every three month? WTF is wrong with the US industry?

The very same cars in Europe will have an oil change every 2 years or so. My Volvo S60 Model 2000 has an oil change every 3 years.

There must be something that you get sold on by marketing that is so wrong. BTW. Also a Tesla has oil in their gearbox, even if it is just a single gear integrated into the single unit combined with motor and inverter. For a Model S it is recommend to replace it every 12.5k miles, which is exactly the very same recommendation as with other car model.

[alistairSH]

Both my cars (late model, US spec, Honda and BMW) have oil change intervals "as indicated" OR every year, whichever is shorter.

The "as indicated" ends up being around 8-10k miles in practice, with start/stop cycles, short trips, and other factors swinging it higher/lower.

These days, we average <4k miles year per car, so use the annual interval.

[maxerickson]

Without meaning to argue that it is necessary, it persists because it just isn't that big a cost. Gas isn't the largest cost of ownership and 5,000 miles of cheap US gas is still ~10x the cost of an oil change.

[vel0city]

> For a Model S it is recommend to replace it every 12.5k miles

There was a recommendation to change the gear oil previously, but newer versions of the S removed those. Even then I seem to recall it was way longer than 12,500 miles.

https://www.tesla.com/ownersmanual/models/en_us/GUID-E95DAAD...

Your vehicle should generally be serviced on an as-needed basis. However, Tesla recommends the following maintenance items and intervals, as applicable to your vehicle, to ensure continued reliability and efficiency of your Model S.

Brake fluid health check every 2 years (replace if necessary). A/C desiccant bag replacement every 3 years. Cabin air filter replacement every 3 years. Clean and lubricate brake calipers every year or 12,500 miles (20,000 km) if in an area where roads are salted during winter Rotate tires every 6,250 miles (10,000 km) or if tread depth difference is 2/32 in (1.5 mm) or greater, whichever comes first

Seeing as how the recommended cleaning and lubrication of the brakes is 12,500mi, I'm wondering if you heard that and got confused about the lubrication needs. As mentioned in their manual, this is really only recommended for places where they salt the roads in the winter. Since the brakes don't get used as much its even worse than a regular car with the corrosion. If you're not in a high road salt area, its not a problem.

The recommended service interval on other EVs also have extremely extended oil change intervals. The service life of the Mach E's gear oil is 150,000mi and the coolant change is at 200,000mi.

https://www.fordservicecontent.com/Ford_Content/Catalog/owne... (warning: PDF document)

If you're changing your EV's oil every 12,500 miles you're either doing it way too often, you bought a defective EV, or you should repair the leaks.

[dotancohen]

I'm not in the US, but I have lived there and I did learn that frequency there. Like I mentioned in another thread, I worked as a service technician at Ford and that was the recommendation then (1990s).

As for the Model S fluid change, thank you for mentioning it, I did not know that. I believe that there is no fluid change interval defined on the Model 3, which I just recently bought.

[kube-system]

There are many gasoline vehicles that specify no fluid changes for certain parts, infamously, transmissions. Longer lasting synthetic fluids allow them to advertise lower maintenance costs, but they still do wear out. They’d rather the transmission wears out after 150k miles anyway.

[dotancohen]

Don't get me started on transmissions! A failing transmission the month after a Model 3 test drive / joy ride is what really pushed me into making the jump to electric.

Thank you for the advice, I will research the service intervals on the Tesla.

[criddell]

Volvo recommends an oil change every 16,000 km.

Because everybody drives differently, mileage and time based recommendations aren't the best. Some places will offer to test your used motor oil during a change and will tell you if you waited too long or changed it to early.