[momura]

Hey my car is having some issues with the heat. The car will warm up fine, and has good heat when Im driving, but the heat blows cold if Im not on the gas. It will become hot again once I start moving again.
This is what my mech. replaced:
-new thermostat (on two separate occasions)
-coolant flush and bleed
-swapped in new water pump.
He suggested to change the headgasket, even though there is no leak in the system...is this a logical idea??
Ive run out of ideas, I need some help before taking the car to the stealership.... thanks in advance!

 

[SPEEDO]

Have checked the control panel (heater) might have issues letting the water into the heater core

 

[vrefron]

Nissans love to get air bubbles in the coolant. Start the car with the radiator cap off, and snap-rev it a bunch of times in a row. The wait for it to warm up and do it again. If a an air bubble is in the coolant, that'll get it out. You likely didn't need any parts at all, though it's always possible.

 

[metro273]

I have a customer at work that's been back on a few occasions for this exact problem. Bled it twice, changed the t-stat and "burped" the cooling system real well. She is still complaining of low heat while at a light but gets hot once they start to drive. I'll be changing her headgasket when she comes back!

 

[momura]

I have a customer at work that's been back on a few occasions for this exact problem. Bled it twice, changed the t-stat and "burped" the cooling system real well. She is still complaining of low heat while at a light but gets hot once they start to drive. I'll be changing her headgasket when she comes back!

Interesting... this is actually my girlfriends car. Her mechanic has tried bleeding the coolant twice - Im not sure if hes credible or not.

metro:I don't understand how the headgasket would solve this problem... there is no leak.

 

[SPEEDO]

At the stealership I've seen them raise(Altima 4cyl) the front end on the rack (engine running) to burp the coolant system

 

[vrefron]

At the stealership I've seen them raise(Altima 4cyl) the front end on the rack (engine running) to burp the coolant system

Yeah, we do that. It works like magic.

 

[kb_b]

I had the same issues as the first person. We change out the themostat, rad cap and water pump and it was still blowing cold air. After a few more miserable days in the cold my mechanic did a test in the rad and found the head gasket was leaking. Thank God Nissan fix the head gasket under warranty. It would have cost me 2300.00. So do the Rad test and check for ses code for engine misfire those are the signs for head gasket problems.