The mileage thread got me thinking about changing or leaving oil at 3K miles? Case in point is Mobil fully synth and Mazda filter, seems a waste but what do you do?
Change oil and filter at least once a year, despite low recorded mileage.
I personally would change both , regardless of mileage , up to you ,
Do you do lots of short drives or few long ones? If the latter, and given you’re using top-quality synthetic oil, I’d do it every two years. That’s the main point of synthetic - it stays stable and effective for longer. If it still looks yellowy-brown on the dipstick it still has plenty of life in it, I’d have thought.
John
I always change both our 5 oils at 5000 miles or a year which ever comes first.
I think 3k with expensive synths and a modern Mk3/3.5 engine is overkill though…provided when the car is used hoever sparingly it is allowed to heat up properly eg 15/20 miles +.
In the case of our 02 Sport ( the former rot box) the engine runs like new at 11 years and 72000 miles on Castrol GTX
I’m just about to pick my 18 years old NA tomorrow after it had new valve stem seals fitted (the Help of Heroes campaign Mk1). The bores and valve (bronze) guides were found to be still tight & within Mazda tolerances with all pots showing even compression at 123,000 miles… and hard (sometimes brutal) ones at that in my hands for the last 6 years. Castrol GTX again. As far as I’m concerned, the only thing that stops reciprocating metal meeting metal is nice fresh oil. Note though, that dirty looking oil does not mean it’s knackered…its doing it’s job suspending carbons.
OEM filters every time incidentally.
Neither car is excessively revved until fully warmed…it’s a family No No!
Make of it what you will!
If you don’t hit the service interval mileage in a year, change the oil and filter anyway.
I have just changed my oil and filter at 2,100 miles since the last change a year ago. All on runs of around 100 miles. Just tells you what sort of summer we have had! I would not let engine oil go over 12 months regardless of mileage.
Regards Geoff Peace.
It’s annual thing along with the MOT even though I’ll have only done 2k. An oil change isn’t that expensive compared to a new enginee. Service intervals are often set to make cars look cheaper to run. Changing more frequently will help make the engine last longer.
i always change oil and filter and air filter every mot regardless of milage
I’ve just worked out that I’ve only changed the oil once in the whole time I’ve had the car… and even then it was only because I was changing the engine!
Russell.
I don’t do a lot of miles these days, so the sump full of Mobil fully synth put in 2 years ago is still clean as a whistle
Thanks everyone 
Being a synthetic user and having recently had a Clio which was 18K/2 year change it did make me think about the low mileage our MX5 does along the lines of John and Geoff’s comments. We only do longer trips in it but, that said, it was surprisingly dark after 3K miles last time. I changed it, Mobil again, and it’s hard to even read the new oil on the dipstick at the mo! Maybe the last lot cleaned some muck out from the previous owners use, we’ll see if it stays a bit cleaner this time. Didn’t use any though and mechanically quiet as a whisper so that’s good news from our first year or so of ownership.
All the replies were very helpful as they made me realise how a prospective buyer might expect to see the service record (if we should want to sell it). So for what it takes I’ll continue to do it yearly as per the time schedule regardless of the low mileage.
I would always change the oil and filter once a year on what ever car i have had
Put it this way - I would never buy a used car that had not had an annual service regardless of mileage. Unless the manufacturer approved otherwise.
Totally agree, would worry about history of car where previous owners obviously skimped on maintenance.
When i viewed/bought my 2nd hand 5 the dipstick oil was fresh.
Nice to see and millage confirmed low use, even so i suspect the seller may have refreshed oil for salesmanship.
I kept an eye on the oil for a month or so. Upon DIY service the oil was still fresh at the stick however, droping the sump bolt black oil poured out, not stinking filthy black mind you.
Id like to say watch out for this however, the truth is i dont know why this would happen.
This plays on my mind a little and effects my choice of when to change the oil/filter.
Any suggestions?
Hi, it’s the same oil on the stick and out the sump, so it would just be the thin film of it on the stick looking clean, compared with the larger volume looking dirty.
A very close friend of mine is quite a high flyer at Porshe and he says that we are very nearly at “Sealed for life” engines. The only service items will be filters and top ups. Yes, I know that this sounds unbeliveable, but he assures me that it is true. It has been known for a while now that modern synth’s are so long lasting that they could be easily dveloped to last 150k! So to answer the op’s question, I feel that a “mileage only interval” using today’ oils should be ok, let’s say 6000? what say you all?
Ive been using VAG/Merc 5/40 full synth and changing at 3000m intervals with filter on 6000m. The oil is the type they use for 20,000 m service intervals. I drain it into a clean tray and give it to my mates who use it in their run arounds with no problems. Its amazing how this oil can last for so long, my mk1 has now developed a slow leak on the rear crank seal so needs a top up of 3/4 L every 1000m or so. In theory i could just keep refreshing with the top ups and change the filter at about 4thou, but i dont think i will some how.