Thread: Looking for proof....

Originally Posted by Disco Muppet

Will a greater percentage of highway speed cruising (100-120km ) "shorten" or "extend" oil life?
I drive a km of no speed limit road than smack onto the highway for the vast majority of my driving, the rest (20%) wouldn't be under 50 unless I'm going offroad. So 80% sustained cruising, 10% average speeds, 10% offroad.

As Dave said, extend, but IMO it's because the engine is operating in a very efficient range of conditions at relatively lean throttle settings.

Stop/start city driving and short trips are oil killers.

IME 15,000km is a step too far in a Tdi. The sump capacity is too small/oil cooling insufficient for the load and power output, particularly if the pump has been tweaked properly (ie. near safe maximum)
I've gone 17,000km on Delvac 1 and the oil test was very ordinary. 15,000km was ok, 10,000km looked like the Patrol @ 20,000km.
Increase the sump size and/or increase oil cooling and it'd be fine.

The TD5 should be much, much kinder to it's oil, as I've often said it has the best oil filtration system of any small diesel ever built but fuel dilution would always be in the back of my head and something to keep an eye (and nose) out for.

I would also like to mention that a 20,000km service interval doesn't take into account other service items, like oil levels ,( in Particular LT230 transfer case leaks....lets face it these things leak and I have seen a few with only a litre or less of oil left in them come service time, if left till 20K it would be time for a new transfer case...) and brake pad wear etc. I have to say to some people that we need to still check these items between services if they won't rectify it AT the service.

JC