Mine used to foul a couple of plugs at the back i think until i ditched the plastic bellmouth, got more low end poke although it idles rougher but plugs are all about evenly coloured now. Yeah it's actually just under 1000 zinc, standard level is about 600-800 in modern oils. Double would be around ...

Although not really related to this thread,I change my trans oil quite regularly and use the same ol dextron mineral oil and they have never been built or apart either :shock: ( apart from filter changes). Yeah I agree with this, the 4L60E definitely prefers the mineral fluid versus the newer synth...

You assume all the oil is filtered. At the end of the day, if the zinc provides extra protection why not use it? Yes we can assume all oil is filtered over the course of time, else why bother with micron efficiency filters?. Not instantly but it will happen and in the mean time the particulates are...

That would be very fine metal in suspension from those cups and done over a long time, which really should be filtered as soon as the oil cycles through the filter. You definitely don't need high zinc oil for the 3800 v6, proof is in fact the sequence IIIG test itself that they happen to perform on ...

Mine also has some wear on the pushrod cups/tips, not really an issue IMO...not enough to justify a lot of zinc. I'd estimate it's got well over 300,000ks and hardly uses any oil (don't know the kays for sure since the odo was stuck when i got it, fixed but it's just gone again). It's had synthetic ...

Hmm, I don't quite agree on this, marketing hype yes absolutely but IMHO we're basically talking about two levels of technology. Sure mineral is fine on old engines like these but you can't say it's better in any way but cost. The lack of zinc isn't an issue unless you're running flat tappet cams wh...

Oh yeah of course you're right there about heat i suppose if that's kept in check the mineral shouldn't shear too much and be fine. It's probably in the style of driving a well, I daily drive like I'm racing so yeah mineral comes out worse for wear. As you say if it seems and sounds better that's an...

Been busy doing little jobs around the house and neglecting the cars, but the Calais needed some loving so it got it's 240,000km service this week (only 1800km late) with some Penrite 15w-40 full zinc mineral oil. It seems to be working even at 12,000km the engine was still quiet like the day I fil...

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