The car will not heat up @ idle but it heats up fine when driving. I did the coolant change myself the same way I have with my rb 240sx with no issues but this isn't case with the vq. Should i go to a shop where they use a machine to do a coolant flush ($100) or should I continue trying to "burp" it?

you have an air bubble in the system. easiest way to fix it is to take it to a shop.

!!IMPORTANT EDIT " My car is not overheating at all ---- " My car is driving and functioning great - no temperature rise/drop.


Heat was coming out of the vents cold only when I was idle - As long as I am driving the car around the heat comes out great- it's cranking hot!

Once I idle the car it begins to cool very slowly until its all cold again....about (5 to 10 minutes)

Took the car into Infiniti Dealer - Paid 125$ for flush/fill coolant and 65$ for a full inspection of the vehicle.

They do the flush/fill heat was working fine after I left.

48.Hours Later -- Heat is coming out cold again when I idle - but if I keep driving the heat stays hot!

I have been checking for leaks of coolant around the engine/block/hoses/etc.

Nothing found to be leaking? I hear the "Water gulping" from inside the car while I am starting to begin to drive. I just bought a thermostat I have not installed it yet- however I don't think that is going to fix it anyway - but that is why I am here.

What have all you found to be happening after this? I have searched the forums and found a few good threads and will continue to post this and read more.

Thank you all for any help or time you give me -

Joe

There is an air relief plug at the back near the transmission dipstick (if so equipped). What I have noticed, is that if there is ANY air in the system, the heater will work inconsistently at low engine speed. What you need to do is go through a few heating/cooling cycles, and after each shutdown, check the coolant level - it should be at max (engine hot). If it is not at max, top it off to max. Drive it again to get it hot (let it cool down completely first), check the level. If the level is where it was before, then you probably got all the remaining air out. If the level dropped again, top off and repeat until it doesn't drop anymore. Also helps to play with the heater controls while you're doing this.

bythabay,

Thank you for your response -

I do hope there is no other serious issue within the car/heat system -
I will be bringing it back to the dealer right away or another mechanic this morning to check the air in the system.

I can't believe that this experienced dealer mechanic did the job wrong.

Even though I am confused of why it worked for a day or two then stopped again...

How could air be re-created in the system? Is there any possible thermostat failure that could cause the issue to come back so soon. I will promise to get back to everyone in the forum about what happens after the mechanic.

If not maybe I will try to do this flush again on my own. Will see -

theres is probably air bubbles still in your system. if they werent patient enough and just did your flush real quick then theres still air pockets in there. easiest way to take care of that is to jack the front of the car up as much as u can,(jacking the car up is to make all the air bubbles in the motor rise up to the surface) find a big funnel that will fit in the radiator cap hole with a tight fit so it doesnt leak, take the cap off and put the funnel in it and let it run. keep it running until the fluid that comes into the funnel stops bubbling. keep topping it off if u need to. dont worry about it over flowing. it wont. and keep the heat on full blast during all of this. give it a few revs during all of this and a couple of 2k rpm holds for 30 seconds each... after about 30-40 min it should be good. sometimes those air pockets dont want to come out and it just takes time to get them out.

WXP-G35,

Thank you for your response to the thread - and the helpful instructions to eliminate the air-bubbles.

I will be at the Infiniti Dealership where they did the flush/fill tomorrow bright and early -

They will see me before they even clock in for work.

Then they will do the flush and fill again - and make sure that it's done properly.

I will come back on the forums to announce the results.

Thank you again... and to everyone for the helpful information here at
g35driver.com

it needs to be burped.

air bubbles dont go away...sometimes they go through the car, sometimes they get stuck. Look at the left side (passenger) of the engine and follow the hose...the hose goes up (elevated) then it humps at the top...thats where your the bubble that is going in and out (or around) you motor is getting caught...keep following that hose to the back of the engine...there is a black circle looking thing with an x on it... loosen it.....make sure the car is off and WARM....not HOT..and slow (VERY SLOWLY) back the vent off..you will hear the air release...STOP TURNING IF YOU HEAR AIR and make a good assumption on going more or stopping... leave loose enough to bleed air.

check your level....add more fluid.

i usually squeeze the hose a few times to ensure all the air is gettin out of the system

refill after it goes down for squeezing the hose....

repeat until it doesnt go down.. I bet you have at least half a bottle left yet to go....

tighten the vent vale not too tight there is a rubber gasket under it so dont smoke it on...

keep in mind the temperature outside is not like summer so your engine wont run too hot anyways...

I am also having the same problem. When I drive the heat works great, but the moment i come to an intersection the air quickly becomes very cold. Temperatures where I am are currently below zero so I need the heat to work well. My car doesnt heat up at all no matter how long you idle it either. I suppose I will bring it in soon to have the cooling system flushed and see how that works...that should take care of any bubbles in the system correct?

Well I have posted to about 3 other threads on here with the same related issue. If you can search them from my name you will find them and read them all.

I won't be surprised if your heat works afterwords and would like to hear from you after you do the flush.