Oil change interval

[enuff_zed]

Which comes back to how many miles it has done with the oil, the more miles the more pollution

But if in the first 100 miles it picks up, let's say, some iron particles and gets a bit of moisture in, then that will continue to corrode regardless if it does another 10 miles or 10,000. In fact maybe there's an argument to say it would be worse as with more frequent use the stuff doesn't get a chance to settle anywhere and is more likely to end up in the filter?
Just hypothesising tbh.

[pvr]

But that is the good part about the discussion, to see what could be or not be impacted.

I was just thinking that the first 5 years of my lawnmower I used to change the oil every year, and have not done so the last 20 years with no visible impact

[enuff_zed]

But that is the good part about the discussion, to see what could be or not be impacted.

I was just thinking that the first 5 years of my lawnmower I used to change the oil every year, and have not done so the last 20 years with no visible impact

Same here

[Nanu]

Isn’t the simple answer that service intervals based on time with no reference to actual mileage just a way for garages to make more money?

For instance how can it be right that a spark plug needs changing after 2 years regardless of use? Likewise filters.

[Ed Doe]

I was just thinking that the first 5 years of my lawnmower I used to change the oil every year, and have not done so the last 20 years with no visible impact

That's no way to talk about your 911

[Zedebee]

Chemically speaking, engine oil is virtually inert, and that applies to mineral oil as well as modern synthetics. The “additives” in modern oil may be more susceptible to degradation, but they are suspended in an inert media, so probably not. The engine is more a less a sealed system, so there is no reason why oil should degrade in the engine (over time) faster than in an opened plastic container.

Wear in the engine is only really a factor of the other crud which is circulating in the engine, which accumulates with use, not time, i.e. metal particles and soot. Metal particles are from friction inside the engine, for instance bearing wear; and soot from combustion products passing through seals and the gradual breakdown of oil under heat/pressure.

Changing the oil every year on a clean engine that only does 300 miles per year is bonkers in my opinion, but it looks great on the service history.

[pvr]

I was just thinking that the first 5 years of my lawnmower I used to change the oil every year, and have not done so the last 20 years with no visible impact

That's no way to talk about your 911

Flush your mouth young man

[pvr]

Chemically speaking, engine oil is virtually inert, and that applies to mineral oil as well as modern synthetics. The “additives” in modern oil may be more susceptible to degradation, but they are suspended in an inert media, so probably not. The engine is more a less a sealed system, so there is no reason why oil should degrade in the engine (over time) faster than in an opened plastic container.

Wear in the engine is only really a factor of the other crud which is circulating in the engine, which accumulates with use, not time, i.e. metal particles and soot. Metal particles are from friction inside the engine, for instance bearing wear; and soot from combustion products passing through seals and the gradual breakdown of oil under heat/pressure.

Changing the oil every year on a clean engine that only does 300 miles per year is bonkers in my opinion, but it looks great on the service history.

Interesting points, that is how I think about it and might skip the service to every other year or so. The service book is full as there are no more pages

[TitanTim]

I guess it depends how long you intend on keeping a car. Say you keep it 20 years and only do a 100 miles a year and don't bother changing the oil and you decide to sell it it, it ain't going to look great with no service history.

For the cost of an oil change every 2 years or so it ain't going to break the bank for peace of mind, regardless of mileage.

Tim.

[Mr Tidy]

Some interesting thoughts here. I'm going to stick to my two years intervals.

[pvr]

2 years seems fine with me, going to drop the annual Golf service though with the mileage that does

[Bear]

Just to throw another anecdote in, I was of the understanding the number of starts/short journeys was a consideration.

[enuff_zed]

Just to throw another anecdote in, I was of the understanding the number of starts/short journeys was a consideration.

Short journeys certainly increase the moisture content as there isn't enough time for condensation to be cleared.