Oil change interval question

[Panamax]

How often would you change the oil in this car? (No, this isn't a "read the manual" question).

Modern car. Petrol engine. No turbo. Does have fancy valve timing gear.
Specified oil always used - fully synthetic 5W-30. Filter replaced at every oil change.
Car used twice a week for journey of 25 miles each time, all year round.
Journey is mostly dual carriageway 70 or 50 mph with a little town driving at each end.
Total mileage 2,500 - 3,000 miles p.a.

Any thoughts on a suitable oil change interval to keep costs sensibly under control?

And just to repeat, this isn't a "read the manual" question.

[Krikkit]

Annually.

Only because it's my personal preference between expense and keeping good condition.

[andburg]

doing it myself? annually
paying somebody else, probably bi-annually

buy a vacuum pump and you can change the oil without the filter or mess alternating years

Edited by andburg on Tuesday 21st February 15:09

Edited by andburg on Tuesday 21st February 15:09

[Scrump]

Annually, which when I change the oil on all my vehicles.

[Truckosaurus]

Annually, at a reasonably priced local garage when it goes for its MoT.

Even if it was an utter shed I'd want the peace of mind from someone having a poke around to make sure everything is still vaguely road worthy, so might as well change the oil/filters while it is up on the ramp.

[B'stard Child]

Annually (for me that's 3,000 - 6,000 miles a year depending on what car)

I try to change it before winter as that's when cold temps, longer warm ups and shorter trips lead to condensation in the engine.

[Panamax]

andburg said:

doing it myself? annually
paying somebody else, probably bi-annually

buy a vacuum pump and you can change the oil without the filter or mess alternating years

Your points are well made. To date I've had this car on an 18 month cycle where it gets serviced at a garage after 3 years but I do a DIY oil and filter change in between.

I've been wondering about either,

• Abandoning my DIY and just get the car serviced every two years, or
• Abandon the 18 month filter replacement and just swap the oil. Your vacuum pump suggestion pulls this well into the frame as the car is a p.i.t.a to get high enough off the ground.

[E-bmw]

Don't just swap the oil but not the filter.

It makes precisely zero sense to put clean oil through a dirty filter.

All or nothing.

As I do my own annual for me, but under your circumstances bi-annual could well be fine, but don't forget shorter journeys will not allow the oil to get right up to temperature to allow any condensation build up to burn off.

ETA, not sure why you don't think it is a "read the manual" question though, as with many cars mileage/time are both constraints for deciding servicing schedules.

Edited by E-bmw on Tuesday 21st February 17:09

[Bobupndown]

I change mine every 10k miles so about every 4 years for your use
I'd say 18 months to 2 years wouldn't do much harm.

[Belle427]

For what it costs annually.

[Lincsls1]

Every 2 years will be just fine with good quality oil and the mileage/usage type described.

[WelshRich]

E-bmw said:

Don't just swap the oil but not the filter.

It makes precisely zero sense to put clean oil through a dirty filter.

Edited by E-bmw on Tuesday 21st February 17:09

Devils advocate, but I’m not sure about this… Contamination/Particulates too small to be caught by the filter will be swirling around in the oil and thus removed when the oil is changed. Stuff that was big enough to be caught by the filter will stay trapped in the filter and shouldn’t immediately contaminate the fresh oil. There’s even an argument to say that a used filter may trap more crud than a new one because the pores are partially blocked (although it would reduce the flow/increase the pressure drop across the filter)

[ChocolateFrog]

Yearly.

Cost in the grand scheme will be small.

[Belle427]

It makes no sense to me to leave an old filter in for the sake of £5.
Makes you wonder how many garages actually do it though.
I once serviced my missus old pug 206 that had supposedly been done every year by Peugeot.
When I took the filter out it practically disintegrated in my hands.
No chance it had been in there a year not even 2.

[E-bmw]

WelshRich said:

E-bmw said:

Don't just swap the oil but not the filter.

It makes precisely zero sense to put clean oil through a dirty filter.

Edited by E-bmw on Tuesday 21st February 17:09

Devils advocate, but I’m not sure about this… Contamination/Particulates too small to be caught by the filter will be swirling around in the oil and thus removed when the oil is changed. Stuff that was big enough to be caught by the filter will stay trapped in the filter and shouldn’t immediately contaminate the fresh oil. There’s even an argument to say that a used filter may trap more crud than a new one because the pores are partially blocked (although it would reduce the flow/increase the pressure drop across the filter)

You are completely ignoring the 1 litre or more that is stuck in the filter etc that drains out when you remove the filter.

[105.4]

Truckosaurus said:

Annually, at a reasonably priced local garage when it goes for its MoT.

Even if it was an utter shed I'd want the peace of mind from someone having a poke around to make sure everything is still vaguely road worthy, so might as well change the oil/filters while it is up on the ramp.

See above.

I do the oil & filter on all of my vehicles every 5000 miles, as two things that engines love are clean oil and clean coolant.

However with your mileage being so low, I’d go for every 12 months, with checking the level on the dipstick every week.

[donkmeister]

E-bmw said:

WelshRich said:

E-bmw said:

Don't just swap the oil but not the filter.

It makes precisely zero sense to put clean oil through a dirty filter.

Edited by E-bmw on Tuesday 21st February 17:09

Devils advocate, but I’m not sure about this… Contamination/Particulates too small to be caught by the filter will be swirling around in the oil and thus removed when the oil is changed. Stuff that was big enough to be caught by the filter will stay trapped in the filter and shouldn’t immediately contaminate the fresh oil. There’s even an argument to say that a used filter may trap more crud than a new one because the pores are partially blocked (although it would reduce the flow/increase the pressure drop across the filter)

You are completely ignoring the 1 litre or more that is stuck in the filter etc that drains out when you remove the filter.

Also, oil filters have a spring-closed bypass valve: when they get sufficiently cruddy for the oil pressure to overcome the spring, the filter is bypassed in order to prevent oil starvation.

So without knowing how blocked the filter is you may end up running effectively without one.

[WelshRich]

I never said it was a good idea, just questioned the zero sense element. If an oil & filter change makes 100% sense, I’d contend that a bi-annual oil only change makes in excess of “zero sense” on a car that only does 3000 miles p.a.

P.H. Pedantry matters

[Panamax]

WelshRich said:

I never said it was a good idea, just questioned the zero sense element. If an oil & filter change makes 100% sense, I’d contend that a bi-annual oil only change makes in excess of “zero sense” on a car that only does 3000 miles p.a.

Yes, I'm inclined to agree. Until now I've had the car in the air to get the oil out so changing the filter was no big deal. But if I were to switch to an extraction pump I'd stop replacing the filter at intermediate changes.

[E-bmw]

WelshRich said:

I never said it was a good idea, just questioned the zero sense element. If an oil & filter change makes 100% sense, I’d contend that a bi-annual oil only change makes in excess of “zero sense” on a car that only does 3000 miles p.a.

P.H. Pedantry matters

I would still maintain that changing one but not the other makes precisely zero sense, the oil costs way more than the filter & takes way longer than the filter to change and there is still a measurable amount of old oil in the engine.

= Zero sense.