750 Engine Seal

[begeta50]

Can someone tell me how hard is to replace all of engine seals in 1990 750il.
And, by replacing the seals would the car stop to over-heat?

[shogun]

replace all of engine seals in 1990 750il

Do you really mean ALL???
In that case you have to disassemble the complete engine. If you cannot do it, it will cost you more than the car is worth.

What is the problem with over-heating? Can you explain that more in detail? Is one or 2 headgaskets damaged? Is the engine losing water/coolant/oil?
Are the coolant hoses hard as if pressure by exhaust gases has been built up in the coolant system?
Have you replaced the thermostat, water pump, fan clutch?
When does it overheat? Only in traffic jam or always, even when you drive Highway?