Pretty commendable kms you have there, whatever you have been doing has been good.
Not too many here, have your kms I believe. Certainly not unheard of. I think the record LC over a million kms was a hz which was an interstate taxi truck in front of long oversize haulage trucks, slow, long distance and steady.
Things eventual wear. Especially on start up. My Dad use to warm up an old 1946 ferguson with a blanket and blow heater...
What symptoms are you getting? Smoke? If so, what colour smoke? Loss of power hauling or uphill?
I have been using penrite oils in Oz, it has extra zinc upon recommendations from here and penrite. I have also used the regular delo, castrol rx and caterpillar oils with frequent changes. I try to keep the oil clean as possible. But I only have less than half the kms you have, so can't tell yet.
I have a pretty accurate oil pressure gauge which shows me the 10w-40 oil gets a bit less psi than a 20w-60 during summer or long 4hr drives. Still both are within spec. We don't get much freezing weather unless in the snow, but we all get hot summers. So , I like the 20w-60 with zinc on my 2h.
I would be happy to get 700k from one engine. Slowly building another engine for fun, love and appreciation, it is interesting. So I will have a spare when the time comes.
I use the flash lube which is meant to be good for valves, but can't really tell if it works. At least it is economical.
lubrimoloy has a diesel purge, that does help clean old injectors. But there is nothing like fresh injector nozzles re-calibrated, which is worth it every 100k kms.
I tried lubrimoloy engine seal fix to hopefully help my valve seals but as it at the top of the motor, I don't think it did much. I don't have any leaks on my 2h. But it did help my wife's 94 mazda which leaked engine oil chronic and does not leak anywhere near as much, amazingly so.
I can't help but like penrite in oz. I have spoken with the oil guy, he knows his stuff. So I go with their recommendation. I do not have any affiliation, don't sell the stuff. They usually recommend heavier oil for oz weather and extra zinc for older engines. Don't like their head gasket leak fix though, I think any of those coolant goops just will help clog things up..
You can buy expensive zinc additives, simply put, it is slippery stuff which helps lubricate flat lifters and solid rockers which the 2h has. Not sure what the hz has.
I also believe virtually all parts for the hz are still available direct from Toyota, which would be like one kind of a heaven!
The Jap imports don't come with records of km's of the donor vehicles they come out of, so there's no real way to verify unless it's possible to 'reverse match' engine number to original VIN and find Japanese records. I don't know if JP registration requires recording km or miles each time rego is renewed.
