C250 Diesel (1996) Coolant Loss

No leaks obvious but some fluid top up necessary every few weeks. Maybe leak is intermittent from somewhere in the plumbing. Contemplating a coolant drain, flush and renewal as over 8 years (130,000 kms) this may
never have been done. Coolant temp rarely exceeds 90 level and have never noticed or heard two electric fans operating either. Only cap in system is on the ballast tank. No signs of pressure in the system as would be caused by a head gasket problem but have noticed main top hose sucking flattish as the engine cools. As with all things Mercedes a clue from another owner could set the matter right at reasonable $$$$ impact! Can anyone out there help on this one. Thanks
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After you drain the old coolant, flush and renew the coolant install a new pressure cap on the tank. Be sure the new cap is the correct specification for the car.
The new cap should end the collapsing hose syndrome and prevent coolant loss.
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Look on the front of the water pump where the pulley meets the pump.
If the bearing is getting loose this is a typical spot for a small leak. as the pump is pretty warm too, this will cause the coolant to evaporate rather then puddle...
Just a thought. Marty
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Many thanks for your help. The new radiator cap has done the trick. No more collapsing hose and coolant loss. Plan to renew the coolant as well.
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