Nissan altima 2001 - I replaced the thermostat andthe radiator and now the heating system blows cold air and the theromostat reading stays above the hot level, but the engine isnt over heating and recently the car rpm starts to reve up and down and the car starts to **** forward.

SOURCE: 2003 Nissan Altima heat problems

take to dealership , that also is a recall problem with alot of altimas , they need to flush system and check water valve , got mine fixed working great ever since , never hesitate to ask dealership about recalls , they have to fix for free

Paul W

• 404 Answers
• Posted on Feb 24, 2009

SOURCE: Nissan Altima no cool air blowing or hot air blowing

Hi!
It appears we have an Air lock scenario and you will need to perform a system Bleed.
Park the vehicle on level ground, when cold remove coolant filler cap, start engine and leave to idle, turn heater on full and blower to max. When engine reaches operating temperature watch and listen near coolant filler, keep clear as gurgling and hopefully a boil over should occur. Top up with very warm coolant and wait as it may do it again.
Check for heat inside vehicle if warm replace coolant cap but keep an eye on temperature gauge as the ~Air lock may have moved on from heater matrix/core so proceedure needs to be carried out again from COLD.

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Paul 'W' U.K

SOURCE: 2004 NISSAN ALTIMA 2.5 NO CABIN HEAT..ENGINE AT OPERATING TEMP.

If the engine is not over heating than most lilely it isn't the thermostat or waterpump that is causing the problem. Check the heater hose coming out of the manifold and see if it is warm to hot. Next check the return line from the heater if it is still cold or moch cooler than the inlet, the most possible problem is the heater water control valve if this model has one or possible the core of the heater is plugg with slime cause by some antifreezes setting during the summer months while not being used. If this is the case than remove tihe two hoses and back flush the heater core with water pressure until it runs clear. I have had this problem before and this cured my problem. I also had to flush the engine and radatior also. Hope this help. .

SOURCE: No heat when engine is at low rpm or idle.

same problem with my 2005 Altima V6, with only 44k miles on it!!! and this is the second winter in the last 4 years that I have to pay for a coolant flush to fix the problem. This time the thermostat is getting replaced too. Time for a new car!

SOURCE: heater blowing cold air

My 05 sentra with 79k miles heat will warm up and then get cold after a mile of driving, we have tried to get the air pocket out, the mechanic stated he thought it could be a blown head gasket, another mechanic said it was a bad heater core. Any advice would be appreciated.