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 :)

Wrong! Wrong! Wrong! You're all wrong. A few years ago, my son's now ex-girlfriend bought a good high-mileage 1999 4 cylinder Camry, which had like 160,000 miles. One day this exact thing happened. She called him, and he went there, put the oil filter back on, tightened it correctly, and added oil. Within half a block the filter BLEW off the car again. It was properly tightened both times. This filter was a Fram Tough-Guard, and clearly there was a manufacturing problem. He put on a genuine Toyota filter and it never happened again. I recommend you use a genuine Toyota filter -- unless that is what you are already using, in which case I have no idea which way to jump -- if you ever get it running again. We told her to send it to Fram, but she was a lazy person and never bothered. I am surprised no one told you to shut the motor off instantly when the oil light comes on, She did and there was no damage.

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.

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.