Car Questions
RepairPal is your advocate for car care advice and guidance

Heating system only gets warm when accelerating cool air comes out at idle.

(2005 Nissan Altima)
in Pottstown, PA on February 05, 2011
when warming car up heat only works when raising rpms or driving. i cleaned out the heater core and replaced the top thermostat checked the bottom one was closed when removed,
Displaying 1 answers & 0 comments
Popular Answer
of Bobbitt Boys Auto Repair on February 12, 2011
Could be several things. Your blend door might not be opening except under acceleration because some are controlled by vacuum. It could also be your water pump's fins may be busted causing not enough coolant to be pumped back into the heater core. Under acceleration the water pump turns quicker. Also, less likely it may be a head gasket leak, pumping air into your cooling system causing an air lock going into the heater core. What I would do is idle the car and check to see if both the in and out heater hose are getting hot as well as both radiator hoses. Let me know what you find out from that.
RepairPal estimates are guaranteed at over 2,000 quality certified locations nationwide. Learn more

Similar Questions

View answers to similar questions from RepairPal's community of auto experts and enthusiasts.
This problem started suddenly. Very rough idle with a repetitive cycle that is smooth for a couple of seconds then mi...
If I drive it around and let it idle for about an hour it gets a little warm, I changed the thermostat and took heate...
Didn't find what you were looking for?