Hey Russ
Yeah I agree. I'm a mechanic, well was 20 years ago, and have built a lot of race engines over the years for rally cars and never had a sludge problem.
The only way I learnt about the flush was when it was on the Toyota invoice for my wifes new Rav4 and I said "what the" and they said it was standard with all the toyota engines.
Beats me why the engines would do it. The current 4 cyl twin cam engines in the rav, camry, avensis etc are all descendants of the 4AGE twin cams that have a fantastic history and I cant remember oil sludging in them. Toyota 4cyl diesels absolutely :rolleyes: . The old 2L and 3L diesels would do the big end bearing if the oil change was neglected much at all.
I wonder if its the euro 2 and 3 regs that are somehow keeping the emissions in the engine and thats sludging them up.
Was it the 4cyl camry?