Service Indicator and Long life oil

[rev-erend]

I understand that some cars like the VW golf TDi have service indicators rather than just the usual service at xxxxx mile intervals.

So - somehow the car knows when it's due a service.

How do these work ?

I also believe they use long life oils - which I presume are just a very good quality oil like Silkoline Pro s with Esters.. but again - if someone knows - please explain.

Lastly - someone I work with said they topped up with an ordinary 'non long life' oil and the car knew this and went back to normal service intervals - is this really possible for the engine to tell - as after reading the OPIE oils thread on this forum - it would seem to be difficult to tell one oil from another without the benefit of a Lab - unless they were just measuring electrical resistance or something like that..

[GavinPearson]

rev-erend said:

I understand that some cars like the VW golf TDi have service indicators rather than just the usual service at xxxxx mile intervals.

So - somehow the car knows when it's due a service.

How do these work ?

I also believe they use long life oils - which I presume are just a very good quality oil like Silkoline Pro s with Esters.. but again - if someone knows - please explain.

Lastly - someone I work with said they topped up with an ordinary 'non long life' oil and the car knew this and went back to normal service intervals - is this really possible for the engine to tell - as after reading the OPIE oils thread on this forum - it would seem to be difficult to tell one oil from another without the benefit of a Lab - unless they were just measuring electrical resistance or something like that..

In many cases the way the vehicle can 'tell' is that the manufacturer does a series of tests that shows the level of oil dilution & degradation under certain operating conditions, like start up, warm up, idle, part load at a variety of speeds & loads, and runing on the lug curve. Then this is also done for diesels with a particle filter under regeneration.
The data is then incorporated in the EMS strategy as an algorithm, which is proven out in field trials to determine adequate accuracy.
The engine management system monitors the way the engine is being run and infers the amount of oil degradation, and alerts the driver at the appropriate point.
I think oil quality sensors are being developed that give reasonable accuracy but the inferred method is the most popular right now.
Having done a project like this I can say that I did it with the oils recommended in the handbook, exactly as a customer would use so you can protect the engine adequately and not cost the customer a fortune. But I am just one person, and I can't speak for other manufacturers or their Engineers.

[rev-erend]

Thanks Gavin.