My disco td5 has lost much power
And making Black smoke when throttle opened, I think the turbo may have failed. Is thee anyway to test the turbo without removing it?

I'm no expert but it could be the actuator seizing on the turbo. I've herd it can stick open or closed. If you r putting your foot down it will inject lots of fule but not getting enough air as the actuator is not letting the turbo kick in.
Worth trying to free off the actuator.

elliot0850 said:

I'm no expert but it could be the actuator seizing on the turbo. I've herd it can stick open or closed. If you r putting your foot down it will inject lots of fule but not getting enough air as the actuator is not letting the turbo kick in.
Worth trying to free off the actuator.

Click to expand...

+1 on that.
From your description, looks like your engine may be running low on boost. Turbo failure usually means oil smoke when the seals fail either on the exhaust turbine side, pouring engine oil into the hot exhaust pipe, or a failure on the intake impeller end which results in loads of oil leaking into the intercooler/ air intake, which can result in a runaway engine in extreme cases.