[quote="turboplanner, There's no problem at all with deciding to change oil earlier than the manufacturer's recommended intervals, but it can be expensive depending on the oil cost. In the example of a certain 4x4 I gave earlier, changing at 25 hours would cost $7,200.00 by the end of 200, 000 km.
Oil Analysis is an alternative to this, since this shows when the oil is starting to break down and need replacement, rather than just being discoloured.
Hi Turbs,
I'm not completely aligned with your alternative suggestion in using oil analysis on economic grounds. In this context, a Jab 2200 engine only hold 2.2lt (really only 2lt) oil lubricant and costs about $30 to do an oil change. The most basic oil analysis will cost a min of $25 to Joe Blogs in the street and more likely $50. It's in my view, it is far cheaper to just change your lube earlier and a whole lot more convenient, as you are not waiting on the return of the results to make a call.
In reality base oils only break down when subject to extreme use, that is very high and sustained temps ... the additives likewise, but more likely to suffer from depletion in their protective properties. If your oil is breaking down, there is without doubt, something else going on in that engine.
I think D10 made a good point ... it's not so much oil breaking down, its contamination in the way of combustion particulates is the problem. Soot related wear is real and will cause wear long before the detergent and dispersants become saturated. Easiest way to deal with this is to change the lubricant.
Lube oil analysis will provide some insight into wear in the engine, but it really requires a lot of discipline to get a good trend (trend is the key) and very accurate records need to be kept and used to interpret the details... this is even more critical in a small engine... large diesel engines are much easier to do, which I suspect is were you have experience.
In terms of managing wear debris in a Jab engine, it really only takes a small amount of training to read the particulates in an oil filter ... this is a very simple and very acceptable way to read the tea leafs on an engines condition and future.
Cheers
Vev