What happens when turbo goes?

[Vineboy]

My 3.1 MU has done 175000ks now and the turbo has been whining since I've had it (25 000ks). When it goes what happens? Will it blow up or just fall apart and get sukced in to cylinders?

[geeves]

A continuous whine may or may not be serious. Sometimes if the car is switched off while the turbo is very hot surface cracks form in the casting. As the blades pass these cracks you get a percusion noise similar to a hellicopter blade but at 150000rpm it sounds like a whine. The whine might also be bearings and it would take an expert to tell the noises apart. If the bearings are failing like this there is a risk of the blades hitting the casing and breaking off. They can eat the insides of your engine but this is rare. My turbo has had a slight whine since I bought it 100000km ago.
The common failure on the turbo on the 3.1 is a loudish whine that is only there immediately after you switch off. This is the internal heat sink comming away from the impellor. As this is on the exhaust side anything that does come off goes out not in so only the turbo will fail. Some fail by just siezing allowing you to limp home slowly but some blow the oil seal so oil gets in the hot exhaustwith spectacular results (esspec if being followed by police)
Its impossible to know how long the turbo will live after it starts making this noise but final failure is instant

[Vineboy]

In other words a turbo dying is usually more of a slow death rather than something instant and severe like a conrod going? I'm worried that if (when) it dies it will take the engine out as well.

[geeves]

There are no guarantees in life. The turbo could damage the engine but it is such a rare event that it neednt be considered