Radiator Water level: W108 280se

[wass28]

Hi, I have a 1971 MB280se W108. I'm noticing the water level in the radiator keeps going down and I have to add about 0.5 to 1 L every week to 10 days. Although there is NO leakage from the radiator itself. Any idea why??

[bwostosh]

If there is no water in the oil,
( Check for chocolate / coffee color oil under oil cap.)

May be head gasket time?
Was the motor over heated?

How does the motor run otherwise?
How many miles since last major motor service?
( valve job ? )

The motor may have 40 years on it.