2002 Altima no heat at idle.

Wild Bill

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MAKE:Nissan
MODEL:Altima S
YEAR:2002
MILES:245000
ENGINE
:2.5
DESCRIBE ISSUE....At idle there is no heat. I am aware of the difficulties purging air out of the cooling system. Just used Airlift system to refill system. It has worked every other time but since this is my wifes car of course it did not fix the problem. Has great heat above 1300rpm just not at idle. Any more ideas?
 

nickb2

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Have you thought of an impeller problem? I have encountered this before in client cars with extreme acidity.

The acidity eats away at the impeller. Low RPM's will cool, but high RPM's will not produce enough coolant flow.

If I can ask a question, were do you live, east or west coast?

Also, is there a check engine light lit?

If PH is way high, look to a W/P or or thermostat or an obstruction.
 

Wild Bill

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No check engine light, I was thinking impeller. The car does not overheat, it just needs to be above 1300 rpm to get any heat. I live in Georgia, only had the car a year do not know it's full history.
 

JackC

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I am assuming you mean no heat from the heater???

I do not understand your impeller theory.

If the impeller is bad there would be hotter coolant , especially at idle.

Therefore there would be more heat instead of none.

Sounds more like a blend door not functioning properly.
 

nickb2

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Very astute Jackc. My impellor theory is when you have checked all that can go wrong.

In a no heat situation.

I encountered this on grand cherokees back in the day. Twice. Fans are blowing, blend doors working. Flushed coolant in both cases.

I am just saying, the water pump in both of those cases proved to be eaten just enough to not provide coolant flow in cold road/area environment.

As usual, I will say that maybe my french is getting the way. I don't think it is a justified excuse on my part, but it has happened before.

I do timing belts all the time. Timing chains rarely, they don't give out. That is why I said/wrote this
If PH is way high, look to a W/P or or thermostat or an obstruction.

I was scratching my head often with no heat conditions. Normal, I live in a cold region of the planet.

Your response is very astute, since he lives in Georgia.

On a altima once, I found easily a no heat condition from continuous rad fans on at all times. So it is always proper to ask the right questions. Two days to understand that the client activated the AC unit in winter and the ac clutch stuck. The pressure sensor was sending to the fans to be on at all times.

You Jackc, ask those. It is good. Helps the client.

:beer:;)
 
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jd

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I hope this is worth asking:

When you don't have heat below 1300, Is heated air flowing from the correct vents becoming cool/cold?

OR, Is heated air now coming from someplace else, like the defrost vents?
 

Wild Bill

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All of the vents are working properly. I just have no heat at idle. Soon as you start moving or tip the throttle to 1300 rpm the heat works fine. The blend door is mechanical and is working. I assumed that it was trapped air and bled the system with a vacuum bleeder, no change.
 

billr

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I know nothing about that engine or cooling system, but advise to check the pump impeller if some other reason isn't soon revealed. If it isn't circulating coolant well enough to get the heater warm, circulation may not be good enough to prevent hot-spots in critical engine areas, like the head(s).
 

JackC

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I know nothing about that engine or cooling system, but advise to check the pump impeller if some other reason isn't soon revealed. If it isn't circulating coolant well enough to get the heater warm, circulation may not be good enough to prevent hot-spots in critical engine areas, like the head(s).
I no nothing about that unit either, and have never experienced that problem, but that could make sense. Especially now that we know the blend doors are working properly.
 

nickb2

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Also, I have encountered stripped/loose wp shafts on many asian models, actually many american also. If memory serves right, these do not have plastic impellers and wont be as bad. But some rebuild companies cheap out.

Those usually happen with high mileage engines, but most often, when a belt is replaced and the wp was not done at the same time, or a low grade rebuilt unit put in place.

Most ppl would think an overheating problem, but when the accumulation has obstructed the heater core from acidity, sometimes a reverse flush will not fix the condition. In extreme cold conditions, the engine will not necessarily overheat.

This is why a ph check is primordial. Then, if all else check out, highly suggest a proper engine flush and removal of the rad cap to see if some coolant flow is happening. If heater core passes water both ways when both hoses are removed, it's not the core.

It is basically eliminating the obvious suspects. Like Sherlock Holmes says in his books, "when you have eliminated the possible, only the impossible remains"

In this snapshot, the first thing they say to check for poor heat transfer is the water pump.

Screenshot (490).png
 
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nickb2

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If at low idle, no go, suspect wp or clogging of the system or a bad thermostat. Sometimes I just remove the thermostat to see if heat transfer happens. It is the fastest and cheapest way to diagnose and safe for the engine in cold weather.

I am not saying to drive the car without a thermostat. Just to diagnose.

Removal of the heater core on these is a pain.

Standard book time is 5.2 hours.

WP is 1.8hrs and thermostat should be under 1 hour.

Checking the heater core for obstruction should be normally a 1/2 hr.

Post back. A non heating car sucks when your driving in your Kanuk coat with big a$$ gloves.:eek: Especially when the kids are on board and you have a long drive. ;)
 
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