Hilux 4x4 Forum

I was just wondering. I got a Prado 95 2002 model with a KZTE engine that I just overall-ed completely.
When I stripped the engine it was real dirty inside, black oil sludge stuck in corners. Cleaning all the parts was a real mission. By assembly of the new engine, one was working very clean, like a theater in hospital. So I assume that the new engine are real clean inside comparing to the old engine.
Now the question is, why do we grew up that a new engines oil need to be replaced after the first 1000 km.? What would the real reason be.?

Morning Hennie,

Good question. It used to be that with older engines it was the case to change the "run in" oil quite soon.
"run in", as in that is literally what it means. A newly assembled engine is "tight"- the clearances and tolerances between the rings and cylinder walls and bearings and journals etc are still settling. That gives off fine metal shavings, which is obviously picked up by the oil and taken to the filter. However, some of these wear particles are quite small and will get past the filter, depositing them into places you don't want them to be. That's the basics of it...

With the newer engines nowadays that is not so much the case anymore to have to "run in" the motor as ( I assume ) technology has come a long way with the likes of machining equipment and efficiency of the new generation engine oils.

I your case, after the overhaul it would be wise to change the oil after about 1500km's or so, because, as is the case for most of us, home garage and most workshop conditions are not ideal for engine rebuilds and dust and other particle ingress is unavoidable..

Oil is not as expensive as an engine rebuild.
Even on a new vehicle where they say it is not necessary, I still let the agents do it.

If you look at the inside of your cylinders after you received it from the engineering shop. It was not as shiny as a used engine, it looked like sanded metal. After you used it for a while it becomes like a mirror. It is those metal shavings (among other things like dust, etc) which lands in your oil. If you do not change the oil, those metal particles becomes grinding paste which will shorten your engine life.

The first 1,000 km oil change in my opinion is non negotiable.