992 GT3 Oil Change

[dr bob]

I suspect it's a gravity thing, and the massive effort put into oil cooling and all its plumbing. I'd be looking for a way to drain all that, but at the same time I'd have to fill it all again completely before I'd even consider starting the engine again. Maybe the need is for flush ports in the to- and from- lines from the engine to the coolers, at the engine end, and a flush tool to pump the new oil in and the old out with everything cold. Maybe a vacuum fill on the external parts to make sure there are absolutely no bubbles or air pockets remaining except at the top of the oil separator tank.

There's some delicate balance when I look at the fraction of GT3's that are driven hard, vs. the fraction that are relative queens that see few hard miles. Both demand comprehensive oil service but for different reasons. The tracked or even hard road miles cars are pretty obvious candidates. The driven some but mostly parked cars end up with combustion products and moisture in the oil, neither of which is captured in the filter. The additive packages in the better oils help with the resultant corrosive concerns. But still, changing only half means half remains.



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Was doing a coolant service yesterday on an early-century MB AMG, with no block drains. The procedure includes 4x drain-fill-run-drain with distilled water before a final fill with coolant concentrate. The math says I end up with about 5% of the original coolant concentrate 'contaminating' the new coolant charge. My Honda Pilot not-summer DD expects a transmission oil change every 25k, but allows less than half of the oil to drain out via the sump bolt. I just change that fraction with every oil change, vs. waiting and doing a 3x or 4x drain-and-fill. Seems there are plenty of other-fluids partial fluid change processes out there. For GT3 oil though, I'd be studying the plumbing and flow paths to determine where to push new oil in and where to draw the old oil out, all with the engine shut off. I'll speculate that the factory-fill process would offer some clues. Apparently, the factory doesn't feel a need to do more even at their own dealer level. Maybe just a little disappointing.

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I'm all for driving a new car home and performing an oil change service, another at 500 and again at 1000. Gets any loose break-in particles out before they do much damage. Modern machining and pistons/rings/bearings need almost no actual "break-in", and most of that is more accurately described as early wear-out. Gearboxes get a similar treatment by the way, for just the wear particles concerns though.

Tom, finding visible metal flakes in the first filter would elevate my heart rate slightly.

[Tom]

Tom, finding visible metal flakes in the first filter would elevate my heart rate slightly.

The tech who showed me (now the service manager) did it for that reason. He knew it would be like that, says they all are on the first change, so opened it up to show me.