IF you want the premium stuff, it comes with a price tag. Stuff like Amsoil isn't cheap, but when you change it you'll find it's cleaner than many other synthetic oils at the same service interval.
Sorry, but if your oil isn't getting dirty it isn't doing its job, the oil is there to lubricate and cool the engine, but it is also there to mop up all the acid junk that petrol produces when it burns. The actual oil doesn't wear out, but the buffering additives (to neutralize the acids ) and viscosity modifiers do get used up. That is why they like you you take the old oil to recycling, they just clean it up, put in some more more additives and the oil is good as new.
The Jazz engines are not super-sport highly stressed engines, so save yourself some money and use Castrol Magnatec Ford A1 5W-30 fully synth, or Mobil Super 3000 FE 5W-30 fully synth - If you want to do your engine a real favour spend the difference on a bottle of Molyslip engine additive - those little super slippery plates of molybdenum disulphide will plate up the bearing surfaces with a film that is tougher that any oil yet made (that's why it is called an extreme pressure lubricant, and is widely used in industry), and are there when the oil has drained away (much better for cold starts). The grease in the CV joints on vehicles is molybdenum disulphide based, which means those bearings can take a proper hammering and not wear out.
If you want the Honda gearbox to be even slicker than it is now, put some Molyslip in the gearbox as well - you will quickly feel the benefit.
And before you ask I don't work for Molyslip - but I am an engineer.
An apology is not an apology if it's followed by "but".
So you're an engineer. Good for you. I've got a lot of respect for engineers. I am not an engineer, but I am a bio-chemist.
Are you a specialist in the field of long chain hydrocarbons, and engine-oil additives? You mention them, but do you know which shear resistant viscosity index improvers are added to the Castrol one you mention or how oxidation resistant the base is compared to the one I mentioned? If not, I'd invite you to research them independently (on your own vehicle) and with the same service intervals.
Look, I'm not going shoot you down over this, and I was being deliberately broad in my use of tech talk in my previous post, but I'll stick to my guns on this one. Not all fully synth oils are the same, and if I could ask you to re-read what I put, I didn't say the Amsoil doesn't get dirty, only that it is cleaner when you change it. Yes, I agree it gets darker because of the simply by products of the internal combustion engine, but there are additives present in some oils making them far more resistant to sludging or small particle impurity suspension, thus allowing them to deposit said impurities in the filter.
This is why I have a filter can cutter so I can check the condition of the filter itself every few services - it's an insight into how the engine is wearing, and you're going to throw it away anyway, so you might as well see how well it's working.
The oil is the life-blood of any engine, so I always use the best one I can get hold of, and different engines want different oils. My personal experience of Amsoil on a motorcycle has been very good.
Regarding additives, I've often sat on the fence with those. Some are clear snake oil (just looking at the ingredients) and anything that says it can add metal to an engine internally, gets a laugh from me. Molybdenum based additives could work, but I've no idea how they affect movement of oil through arterial pathways to the top of the engine, so I've always gone for regular oil changes. In a gearbox, I'm with you all the way and I suspect they would be great. Ours s great at the minute, but it's worth trying whilst it's good to see what happens!
