If you take it into any 'main agent' garage, the bill for diagnosing the problem is likely to be more than the car is worth.

In your position, I'd try solution c. as you've given above. It's almost free, and if it works then happy days.

If not, then you've got to decide if you want to spend money on the car, and how much. Or if you're happy to keep adding 1L of cheap oil every few hundred miles until it goes bang or fails the MOT test.

I would advise against using thicker oil than recomended by the manufacturer for several reasons.

Engines are manufactured to much tighter tollerences today than they were in the 70's and earlier when thicker oils were the norm. Even when the rings are worn the pump still has to circulate oil around the reat of the engine which is probably in fine fettle. Thick oil will make the job of the pump much harder and when its cold will take a considerably more time than a thin oil. During this phase wear on the cams and other components will be accelerated.

Oil in an engine also performs a cooling function. Thick oil circulating slower cools less and the extra friction pumping it also creates more heat.

Engine manufacturers know a thing or 2 about the best oil, they do test you know.

Oil does not need to be thick to prevent wear like it did (or did not) in earlier times. Remember those times, rebuilds every 30,000 miles, I do (just - on dads cars).

Good quality oils are available at reasonable prices. Tak our Kia as an example. It requires fully synthetic 5w30 C3 spec which is DPF friendly. The dealer charges £60 for oil at a service which is pretty normal in my experience. The dealer is quite happy for us to supply our own providing it meets the specs. Just bought some ASDA oil which meets the specs and is even approved by Hyundai/Kia for use in their engines. Cost £15.

So I would suggest just continuing to use the car and use a good quality oil that meets Toyota's specs. A litre of oil every 500 miles is not going to break the bank. At the price I paid its only £60 a year extra.

Edited by skidpan on 11/05/2015 at 17:54