300 TDI ...75% powerloss

Hi Guys
I'm 47, a Landy lover, have rebuilt 3x 300TDI's and 1 x 2.25 petrol and a 1980 3.5 Range Rover.
I am a lodge manager in Zambia, and we own 2 x 300 TDI's, and 2 x 2.25 d gameviewers.
My current problem is one of the 300 TDI,s with a 75% power failure. The car runns well and then when it reaches normal temp it looses 75% of it's power.
I have :
Checked all the turbo pipes for blockages and tears...none found,
blocked off and disconnected the EGR,
replaced the exhaust manifold gasket,
replaced the lift pump,
relaced the air filter,
replaced the fuel filter,
hot wired the positive onto the IP.

There seems to be some pattern here, and that is running temp. As soon as it reaches normal running temp it looses 75 % of it's power.
It does not smoke, there is no excessive smoke, and no water in the sump.

Can any body point me at something I should check...in order to solve this problem?

ari

Has the turbo siezed?

Make sure the turbine is free to turn - take the inlet pipe off it and try to turn it with your fingers.

If you can find one, try to fit a manifold pressure gauge. It should hit +12 psi about 0.7 or 0.8 BAR when under load.

Next step would be the check and clean the turbo boost compensator device on the top of the injection pump. These are prone to getting full of crud, and jamming up. The result is the sort of power loss you describe.

Good Luck!

CharlesY