Q: No heat. I've replaced waterpump, thermostat, heater control valve, heater core, auxilliary water pump 1998 Cadillac Catera

asked by on January 07, 2017

No heat....replaced all coolant related items. Also replaced control head.

My car has 197000 miles.
My car has an automatic transmission.

Hi there - the lack of heater function could have 5 causes: the engine is not getting up to correct temperature (center of the gauge) due to a malfunctioning thermostat, the heater control valve is not letting hot coolant into the heater core, there is a restriction in the heater system that is preventing adequate hot coolant flow through the heater core, the heater fan is not working to transfer heat from the heater core to warm air for the passenger compartment, or the air blend doors inside the heater are not working properly to route warm air to the desired vents. I would recommend a heater system inspection](https://www.yourmechanic.com/services/heater-is-not-working-inspection) by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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