Specifically what are the causes of the Toyota oil sludging problem?

I have not experianced this problem since my 2004 Camry 4 cyl. motor has had Mobil 1 directly after the first oil change. The oil has always been changed at the 5,000 mile factory recommended intervals. Inside the valve cover looks like a hospital operating room. I did see a V6 motor apart at the Toyota dealer and the tops of the cylinder heads had gobs of grey / black build-up. A salesman tried to smooth my feathers by telling me that the owner was using 10-W30 instead of the recommended 5-W30. Personally it looked as if the oil had never been changed. Too many people are having this problem and I can't figure it out.Specifically what are the causes of the Toyota oil sludging problem?
The key to long engine life is to change oil more often, its good you are using Mobil 1, but i would never recommend waiting until 5k miles you engine wont last long if you wait that long. change it every 2,500 miles and i would recommend changing your oil filter as well just to be sure. otherwise your engine wont last very long... just remember the more often your car has fresh oil the better... synthetic helps on top of it as well although normal oil is just as fine i would just recommend changing it sooner like 1k or 1.5k miles.





stick to what they recommend your car to use, 10w30 will do exactly that because I'm very sure he is not required to have it... as in living in a very hot climate... the oil is for your expected heat range... on of course on that car its not high to need 10w30 unless you really need it... (turbocharged, in the desert during the summer etc etc)





just remember, the more fresh oil your engine has the longer it lasts... period... and the more often its cleaner the better... so spend the extra couple of dollars on the better filter as you are already spending the extra dollar on the better oil..





any engine trouble you see about someones car is bad oil cahnging habits, the #1 cause of the people stuck on the side of the road :)Specifically what are the causes of the Toyota oil sludging problem?
Change the oil every 3,000 miles regardless of what the manual or the manufacturers say, every vehicle I've ever had I've always changed oil every 3,000 miles. Oil breaks down after time, and will eventually lose its lubricating qualities and turn to sludge, gumming up internal components which eventually leads to engine damage and failure.
Specifically? lack of regular oil changes and/or using non-detergent oil.





MY Camry I4 motor is clean as can be. Oil is changed at 3K miles, as this engine seems to dirty the oil faster than my V8 Tundra does.
Toyota designed the oil jackets in their engine blocks too small, therefore if you haven't changed oil frequently any impurity will block the flow through that channel.





The kings of quality created a poor engine design.





But i think if you keep the oil clean, change the air filter at 10-12K and take care of the engine, you'll be fine.