jeankilani

hi, help please, my 1995 s420 is overheating, electric and mechanic fans working properly fan clutch is good, I replaced water pump, thermostat, duo valve, flushed and cleaned radiator, still overheats.

when air condition is off there is no problem, also mid vents don't put out air, and no hot air when running heater... is there an auxiliary water pump and if so where is located?
thanks

KNBS550

Did you make sure that you got all the air to escape out of the radiator and the entire coolant lines? When my mechanic replaced the coolant, he ran the engine with the cap off the coolant expansion tank to make sure all the air went out. Check that first.

jeankilani

Thanks I will try that

jeankilani

that didn't work

KNBS550

You have...
1) New water pump
2) New thermostat
3) New duo valve
4) New radiator coolant fluid
5) No air pockets in system

Interesting that you have no hot air even though duo valve was replaced. Are you sure the twin auxiliary electrical fans on the radiator is working? Sometimes people mistake the radiator fan operation with the engine fan. Could be the relay for the electrical coolant fans.

Otherwise check the engine coolant temp sensor. It is a cheap enough replacement.