Toyota Aurion Problems

I wouldn't worry too much about it, but I would monitor it and if it does get worse I would take it back to the dealer and have them repair it.

It's good to hear that your car was fixed; it's also good to hear that there are still mechanics working at dealers who know how to fix cars and not just replace parts.

If it is only a slight leak you could probably continue to drive it, but if you did it would only get worse and you will eventually have to replace the pump at your cost. I would accept the offer.

It does seen unreasonable to have to remove the engine to fix an oil leak at the timing cover, I would take it somewhere else and get another quote. Oil leaks are not uncommon on Toyotas, as they are on other models, so I would doubt that you would win an argument that it wasn't wear-and tear. If the leak isn't a bad one then I would think you could carry on for some time before you needed to have it fixed.
 

You say the car had a poor service history when you bought it, and there was sludge under the filler cap. Both should have been warning to you that this car hasn't been well cared for; you are now paying the price. Sludge builds up in the oil galleries when the oil isn't regularly changed, and if let go long enough can cause blockages that can be fatal to an engine. It's rattling, using a lot of oil, and blowing a lot of black smoke, you should have it pulled down and inspected, and possibly rebuilt.
 

There are two schools of thought here. One is that by regularly   cleaning the injectors you will avoid trouble if they clog up, the   other is that it's the dealer selling you an unnecessary service to   make more on the car service. I tend to go along with the latter.

We haven't had any other reports of a failure of the VVTi hubs, but perhaps other readers might tell us of any failures they've had. The outcome you've managed to achieve is a reasonable one.