Jim Grant's Tech Tips
'89 Nissan Maxima
the thermostat, and I still don't have any heat. When I turn on the heater,
it starts out warm, and then goes quickly to cold.
the temperature gauge on the dash indicating that the engine is warming
up correctly? Is the coolant level correct? If the answer to both questions
is yes, then it is possible that you have a restriction in the hoses,
control to the heater core or the heater core is restricted. If the coolant
flow to or through the heater core is restricted, it is common to have
heat for a few moments when the heater blower is first turned on. Then
the temperature drops. Youll need to have a technician check the
coolant flow rate to the heater core. The solution may be as simple as
back flushing the heater core or as costly as a replacement.