Yes Peter, dip stick is still showing "full"; it doesn't use any oil between services. If it had a diesel engine I could maybe understand - if maybe the DPF had dumped some diesel oil into the sump,.. then maybe my engine oil might have been diluted and might then self--ignite and my car might then eventually burst into flames - as so many diesels seem to do ;o). But this is a petrol engined Astra. Thanks for your interest.

What does the owner's manual say?

Perhaps the 'oil at 1%' message means that it's approaching the end of its intended service life, and is just part of the ECU's nagging programme aimed at getting you booked in for a service.

The current generation of Volvos starts counting down to the service a month before it is due, flashing up a 'Book Service' message EVERY time you start the car. It's not irritating at ALL.

If your dipstick shows full, the oil doesn't stink of petrol, the engine isn't using any coolant, and there are no unusual noises from it, I would just continue driving as normal until the service.

Owner's manual give no clues. I'm sure you're right: it must surely be, as you say, "just part of the ECU's nagging programme aimed at getting you booked in for a service". But when the service team said: don't drive it til you come in for service, that's surely a bit rich. Right now, I've a daughter-in-law who - over the next few days - is about to go into labour,... and I was thinking: am I going to have to get a taxi to take her into hospital? Thanks everso for your thoughts on this.

Unless the GM oil monitoring system has changed without my knowledge, It just uses an algorithm that is calculated using data from the sensors connected to the ECU. It does not directly have any way of testing the quality of the oil.

I'd agree with Craig, If the oil looks and smells OK then it should be fine to drive until the service.

What does "Oil at 1%"really mean please? Garage says: don't drive it til you're bringing it in for the service.

I guess its brainless computer has calculated 361days since the last service. It is trying to convey the absurd belief that your oil will significantly lose its lubricity and protective qualities at the stroke of the 365th midnight.

Use your common sense allied to a bit of basic scientific knowledge (physics and chemistry A levels will do) and remember that this site is patrolled by many whose living depends on strict adherence to the dogma of manufacturers' sales departments. Any dissention sometimes results in invective so unpleasant that it requires the attention of a moderator.

It'll actually use an algorithm based on throttle opening and number of cold starts as well as mileage - so if you drive a car hard it'll signal an oil change earlier.

You're well known here for using exceptionally long change intervals - no-one else who cares about cars does that.

Fresh oil gets rid of contaminants as well as maintaining lubricity.

Edited by RT on 03/03/2016 at 10:29