Have 97 Disco 1, 170K, previous owner operated on beach sand with significant fluid leaks. Now I have oil & dirt scum from radiator cross member to behind cats. It is 1/8th to 1/4 inch thick in most places. Used spray car wash with engine cleaner, did not get much, left wave pattern in the sludge on some chassis parts. Used Purple K and brush, very slow going. Used tiny "steam shark" steamer, does work in small areas. Found leak on front seal, vehicle seems to have thicker coating of gunk on driver's side, may have steering box leak. Coil springs normal on right side, coated 1/4 inch on left side. Note: I had already found the PO had seldom cleared the oil separator for the valve cover, which may have contributed to the seal leak. With four hours in it so far, I have made it from the radiator to the front of the oil sump.

Any ideas or precautions would be appreciated.

 

Have it steamed cleaned while on a rack.

 

Just take your time.
You dont have to remove it all at once either.

 

you could try spraying some cheap carb cleaner of the wal-mart brand...