# No Heat when Driving in Winter



## brewmeister (Aug 27, 2004)

94 Altima.

When car is moving, temp gauge drops, and no heat in car.
Thermostat replace 3 times in 2 weeks last winter, no results. Fine at idle speeds.

New Rad and hoses, heater core checked and flushed.

Any ideas?

since it is still summer, I cannot verify much right now, but winter is only a short time away (here in north eastern Canada)

I am looking for ideas before the cold hits again...


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## SPEEDO (Jun 9, 2003)

well, have you checked the actuators that control the doors in your heater box? they open or close depending on... heat to the floor or face etc or maybe the heater control itself.


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## Asura (Aug 27, 2004)

... looks like the thermostat got stuck open or else opens too early.. what temp. was it spec'd at?

ok... here's a test... cold start up, remove radiator cap and start the car. watch the coolant, watch the radiator fan.
the coolant may move from engine vibration, but there shouldn't be a moving stream on cold idle (thermostat close position)... if there's a moving stream... then thermostat is stuck open.
see if at any point the radiator fan turns on.


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## brewmeister (Aug 27, 2004)

SPEEDO said:


> well, have you checked the actuators that control the doors in your heater box? they open or close depending on... heat to the floor or face etc or maybe the heater control itself.



I get heat when the car is idling after a few minutes to warm up.
But this has stuck in the past.


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## brewmeister (Aug 27, 2004)

Asura said:


> ... looks like the thermostat got stuck open or else opens too early.. what temp. was it spec'd at?
> 
> ok... here's a test... cold start up, remove radiator cap and start the car. watch the coolant, watch the radiator fan.
> the coolant may move from engine vibration, but there shouldn't be a moving stream on cold idle (thermostat close position)... if there's a moving stream... then thermostat is stuck open.
> see if at any point the radiator fan turns on.



I have a factory thermostat...I beleive that it is around 77 degrees C(I could be wrong on this now). It has been replaced 3 times, twice in a shop where a complete cooling system test was done. In the shop it shows no issues, only at moderate to highway speeds in very cold weather will it act up.

It was suggested to me that when I had the belt changed last year, it could possibly be running the wrong way on the water pump, there by circulating the coolant in the wrong direction....how likely could this be...I will have to see if the belt matches up with the diagram this weekend. Is this even a possibility?

Thanks for the responses.


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