Oil Change Interval Question.

  • Last Updated:
  • Oct 17th, 2015 10:18 pm
Sr. Member
Sep 27, 2009
724 posts
CanadaMaple wrote:
Oct 17th, 2015 3:15 pm
Pretty basic question, yes I should know this already.

Mechanic says I need to change my oil every 5000km, I never have (do my own oil changes).
Always do 8,000km.

Oil I buy says good for 12,000km

My car's owners manual says I can go 15,000km.

My car does not burn any oil, and I'm coming near my interval, and oil quality still looks good.

I drive over 1000km a week.

I also change my oil filter every oil change, however the Mobil1 filter I use says its good for 24,000km. Is it okay to start changing my filter every other oil change?

I use synthetic 5w30

Car is a 2001 A6.

All this taken into account? Which oil change interval should I be following, after 8000km, my oil dipstick still shows oil at the full mark as well.

Instead of the regular Mobil 1 oil, buy Mobil 1 Extended Performance. On the Jug it says it is good for up to 20,000 KM and should easily last 15,000 KM as the manual says. Also use a Mobil 1 Extended Performance filter and you are good to go. Out of the two Mobil 1 Oil varieties, the regular Mobil 1 is not 100% synthetic, whereas the Mobil 1 Extended Performance is 100% synthetic.
Deal Expert
User avatar
Feb 8, 2014
15891 posts
Oil wears out when its acid neutralizers and additives are worn out, oil change intervals are conservative guesses based on averages, cold starts, distance per trip, highway/city driving, engine loads, weather/humidity, engine wear characteristics etc. Under warranty follow the automakers suggestions since they will deny coverage for any excuse they can invent, but otherwise stretching it a bit under light duty (warm weather, long trips per start, non trailer hauling/low load etc) is likely to not be a problem. As was mentioned an analysis is the only sure fire way to know how much life you have used up, but costs a pretty penny for us canucks.

Mechanic is giving you outdated advice, i'm surprised the oil says an interval, and if the automaker is happy with a long interval then use it. You might consider switching to a better synthetic oil and 15k should not be a problem. At 1000km a week you likely don't have short trip cold engine water condensation problems, if its highway driving then go with the 15k interval. The 24k may be doable with the proper oil, but personally i would buy it and get an analysis done at 15k and see what the results are, the savings or peace of mind is totally worth it at 1000km/week.

BTW oil level has nothing to do with oil life, and you can go to bob is the oil guy if you want much more technical answer from engine oil nuts.
All spirits are enslaved that serve things evil
Deal Fanatic
Oct 26, 2008
5854 posts
CanadaMaple wrote:
Oct 17th, 2015 5:32 pm

Most of my driving is highway.

car takes about 6.5-7 quarts
2 key points right there.

Be guided by the Owner's Manual but interpret it according to your own circumstances rather than take it as gospel.

This is a 14 year-old German car, not a late-model Honda in-town runabout with a 3.8L oil capacity and a throwaway canister filter.

15K km. interval is fine. Reduce to 10K if driving pattern changes to shorter trips.

Not using any oil between changes is commendable, but either way it doesn't impact the change interval.
If anything, when it does start consuming some oil you could extend the interval because you are refreshing the additives with top-ups between changes.

And it's unlikely that when it does start burning oil it has anything to do with change intervals, oil brand, filter quality, etc. It is just going to happen sooner or later whatever.
User avatar
Dec 9, 2008
419 posts
Ken_vs_Ryu wrote:
Oct 17th, 2015 5:54 pm
Are you babying your corolla
Not really I do 5000km a year on my lada , so 2 oil changes is all it needs
Sr. Member
Dec 15, 2013
959 posts
North of Toronto
elkhaze wrote:
Oct 17th, 2015 3:58 pm
I change my oil between 2000km and 3000km depending on weather and free time. And filter every 5000km. DIY and drop used oil at CT. Cost me $35 for 2 changes every 5000 km for conventional oil.
That is unnecessary and over kill.