I have a 79 series v8 turbo diesel landcruser the engine check light comes on at random the engine then derates if you stop and shut the engine off restart it the fault goes away for the time being

youtube its a oil and filter motor landcrusier demo
Toyota Land Cruiser 200 Series Engine Oil Change

There are different parts manual for each truck. I bought one from reliable-store for my Land cruiser 70 pickup truck.
check out yours-
Best Manuals

most diesel timing belts need to be changed every 60 to 80 thousand miles alway worth getting checked as if it snaps or skips teeth it can cause serious damage to the engine

It will be a diesel oil only, with a viscosity rating of 15w-30 or 20w-50 depending on the ambient temperature of your area. The brand is immaterial but it has to be diesel oil to have the ingredients needed to run a turbo. Oil used in a petrol engine will not be suitable for this application.

well it runs,,,,,
low power on a diesel is
1: low compression
2: bad fueling
#2 can take forever to find, if you dont know what engine it is or what fuel system was used.. no country stated, so cant guess
read the wiki on land cruiser and see what you have.
we dont know.

series 80?
series 100,200 ??? what?

• 4.5 L 1FZ-FE I6 gas
  
• 4.7 L 2UZ-FE V8 gas
  
• 4.2 L 1HZ I6 diesel
• 4.2 L 1HD-T I6 turbo diesel
• 4.2 L 1HD-FTE I6 turbo diesel
• 4.5 L 1VD-FTV V8 turbodiesel

one of those last 4? engines?
once there, we try to find out how it works. each varies.
can fix engines with out knowing exactly what it is, and the injection system, used.
cant.

possible air still in the pump so bleed at the pump

It maybe the problem of V8 6.5 turbo diesel. To use the turbo success, the car must be reached the high certain speed. So it maybe the normal that whining sound coming from engine. Diagnostic engine regularly.

it yhas a 350 5.7 ltr

I want to change the engine oil in my 200 series cruiser how do I get to the sump plug & filter.

set ur engine at top dead center get tappet clearence data from manufacture using feeler gages adjust