Replacing the water pump on a 1993 2.3 liter Mercedes 190 is fairly easy, so may I assume this is the 2.6 liter engine? The labor time for this job is 7.5 hours for a very experienced technician, a full day’s work!
Coolant should be drained and the following components should be removed in sequence: lower engine cover, air filter intake boot, fan shroud (unbolt but leave hanging around the fan until fan and fan clutch are removed). The serpentine belt tensioner assembly is removed next, then the pulleys for water pump and fan. Dismount and set aside the A/C Compressor without removing refrigerant hoses or discharging the A/C system. Dismount and move the hydraulic pump, remove the thermostat housing and at last, the water pump. A special, long-handled 8mm allen wrench, which is available from tool manufacturers like Assenmacher Specialty Tools, is used for removing the fan clutch.
Chino Autotech Inc., Auto Club SoCal AAR
SAE Int'l SoCal Section Board of Governors
Vice Chair, Service Technology Programs
NASTF Service Information/Communications Committees
Auto Value/Bumper-To-Bumper CSC Nat'l Council
ASE CMAT-L1, CA. Smog Check Technician
AMI AAM Accredited Automotive Manager