I have a 1995 Maxima with climate control and the heater only blows cool air. The engine does reach normal operating temperture as usual within a few miles of driving so I guess it's not the thermostat. I assume the electronics/mechanics of the climate control are okay because the air is a little warmer at the 85 degree setting than it is at the 65 degree setting. Last summer my radiator was replaced and the mechanic reconnected the hoses without flushing the system. There was a gooey rusty looking substance in the radiator at that time and the hose connecting the radiator and the overflow reservoir was totally crudded up with this substance (which I cleaned up at that time by running a wire through the reservoir hose).

I'm not mechanically inclined, but after reading similiar posts here, I'm guessing that I have either air in my coolant system or my heater core is crudded up. I did see in a post that there are bleed points on my engine, but because they've never been opened up before, I'm concered that if I try to open them, I'll have a leaking problem. I also saw a post on an earlier generation maxima that running my car 30 minutes on an steep incline might solve the heater core air pocket problem, but I'm concerned that oil won't reach the engine while running it for that long a period at a steep incline. (I pasted that suggestion I found below}. Any advice or suggestions are appreciated.

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Nardia:
I have a 1990 nissan maxima and i can't get any heat inside. the heater blows cold air most of the time. what may be the problem?

Krick:
03-03-2005, 12:15 PM
You might have an air pocket in the heater core...
System: Heating/Cooling
Symptom: Poor or no heat from the heater. This may occur after cooling system service.
Problem: Air is trapped in heater core.
Background: If you encounter a 1989-1991 Nissan Maxima with a complaint of poor heat from the heater, check with the customer to see if any cooling system service has been recently been performed. If so, air would have entered the cooling system at that time. If not, check for any leaks in the cooling system that could result in air getting into the system. The heater core in these vehicles is the highest point in the cooling system so if air gets into the cooling system, it can get trapped in the heater core and result in poor heating.

Fix: Make sure the cooling system is: free of leaks. Raise the front of the vehicle off the ground so that the bottom of the front bumper is approximately 39 inches off the ground. This will allow the top of the radiator to become the highest part of the cooling system. Make sure the cooling system is frill of good 50/50 mix of coolant and water. Leave radiator cap off. Set the heater on full hot on the manual systems and on 85[degrees] on the automatic climate control systems to let coolant through the heater core. Keep A/C off to keep the cooling fans from running continuously which could prevent the thermostat from opening. Run the engine at l500 rpm and warm it up completely--you may need to run it up to 30 minutes. After bleeding the cooling system in this manner, turn off the engine, make sure the radiator is filled and put the radiator cap on immediately. Lower the vehicle and make sure that the coolant overflow bottle is filled to MAX level mark. Let the engine cool down completely. You may need to r epeat the procedure to make sure all the air has been removed. Note: Nissan has released a revised coolant bleeding procedure to address this issue.

I would check the blend door first. It is a flap that directs whether the air comes from the interior, or is pumped in from outside.

You can find useful info on the heating and air system here. http://www.nicoclub.com/FSM/Maxima/1995/ha.pdf