Oil Change Time ?

[marinabrid]

hello all

since moving house the old tdi 110 98 reg only goes around 3 miles a week to the supermarket, its not even getting warm before its turned off, i try to give it a 20 mile round trip to the mother inlaws once a month but this is now not getting done due to work.

how often should i change the oil doing this kind of running. i last did it in december and have done 300miles since getting to temp around 3 times on that milage, the rest of the miles has been never a warm engine.

[sepulchrave]

It's contamination from blowby on old tech diesels like yours which affects the oil condition, so if you're barely using it then a time rather than mileage change is appropriate, although if you're using a quality synthetic then even that isn't really important, December 2009 will be fine in that case.

[marinabrid]

what does the term blow by mean ?thanks

[sepulchrave]

what does the term blow by mean ?thanks

 

It means combustion gases being forced past the piston rings into the cylinder block thereby contaminating the oil in the sump with fuel and exhaust gas products etc.

 

It's why the oil turns black and sludgy over time and mileage. It happens in petrol engines too but far less due to the much lower effective compression ratio.