Z350Lover

iTrader: (2)

Hi guys,

I noticed that the A/C heater doesn't work at all even if I turn the dial all the way to the hottest setting... but it still blows cold air though... it just suddenly becomes like this and I have booked in for the dealer to check that out tomorrow...

But this morning, my car got over heated (after about 2 miles of driving from cold and the temperature went all the way to "H") and the coolant flew out from the reservoir tank... I was like WTF.. this was actually the first time that happened to me.... and I got the car towed to the workshop and had the pressure checked out, nothing's wrong with the car, so they filled in some more coolant for me (although the reservoir tank is way over filled), I took it for a spin and suddenly got the heater back... but just for a few minutes.... and it is gone again now.... but the car never overheats again from then though...

Does any of you know what's the problem here? Please give me some ideas on what should I ask nissan dealer to look into...

thanks heaps!!!

cheers,

richie

overZealous1

iTrader: (27)

sounds like the head lifting issue perfectly. but you are not f/i so it is kinda weird. unless you are lightly detonating i doubt you would be creating the cylinder pressures needed to do this.
the heater core is the highest part of the cooling system, so when your heater goes, you know you are low on water. now unless you never completely got the motor filled in the first place, i find it hard to believe you are having head lift. but your symptoms say it to the T. the reason for the overflow tank being full is because that is ultimately how you are loosing the water, if you were just overheating, the excess water in your overflow would suck back into the motor once it started to cool down.
i would make sure you fill the car completely, the best way to do this is-

fill radiator and overflow as much as possible with the rear vent open, start car up and run at 3k for about a minute. wait a few for the car to cool. repeat this process about 4-5 times. once your heater blows hot at idle, you are pretty close to done. drive the car for a day with a full overflow tank. let it sit overnight and check levels one more time. that should do the trick.
if you keep loosing water after that, there is a good possibility you are getting light detonation and pressurizing the cooling system from excess cylinder pressure leaking into the cooling system and purging water out the overflow. do you see any signs of water stains on the bottom of the hood or anywhere around the overflow tank? is there little black specks in your overflow? these are signs of a leaking headgasket.
good luck

Z350Lover

iTrader: (2)

thanks mate....

The odd thing is that it only did ONCE... and we did nothing but just to check the radiator pressure and pour more coolant into the radiator... then I went for a spin even up to 8000rpm several times... no problem at all... then I even noticed that my heater worked well too.... but when I came back to the workshop, the heater starts to become cold air.... and never have the over heat again though... also noticed that there was a hissing noise at the nismo radiator cap when I open the hood, so I replaced that with the stock cap... and there is no hissing noise anymore....

I took the car for a drive for several times and no over heating at all now...

But the heater still doesn't work though....

Any thought on that?

BTW, don't find any black things in the reservoir tank though

thanx heaps!

richie

Z350Lover

iTrader: (2)

sorry for not undestanding the term used.... what's a rear vent??? about filling the entire engine

cheers,

richie

Z350Lover

iTrader: (2)

overZealous,

I tried your method of filling the car complete.... and it seems to work though.... after doing that and a few runs (2 mins runs on the road only at constant rpm), I can get hot air.... and the engine temp. is at the normal temp as well, no sign of over heating... and the reservoir tank coolant remains the same amount before and after... so what's this filling the car anyway????

I will test it out tomorrow morning again to see if I still have the heater....

cheers,

richie

Audible Mayhem

iTrader: (48)

the overheating problem is the part that makes your story so weird, even if something in the heater core got stock there is still the normal route that should bypass it. maybe possible the thermostat got stuck. i took out my thermostat and hollowed out the spring and guts outta it and it runs 30 to 40 degrees F. cooler under normal driving conditions. i was at close to 190 F and now it runs in the 150Fs all the time.

my heater wasnt working correctly when my coolant level was low though...

good luck mate i wish i had your hp range right now NA i am only in the 260s range putting down some decent quarter mile times in the states here. helps being a good driver too!!

MIAPLAYA

iTrader: (3)

I doubt its a lifting issue. My car did this when my thermostat failed. And its happened twice so I know its exactly what you are describing. Just as a test pull the stock thermostat housing and remove the actual thermostat itself. Re-install the housing and try it again. I bet you it doesn't overheat..

overZealous1

iTrader: (27)

ya, as said earlier, you want to keep doing this refill process until your heater blows hot at idle. then you will be full. the hissing sound is from the limited amount of water boiling in the motor and it is venting because of the expansion of the water due to boiling.
vent is behind the passenger side of the motor on the heater core line. it is a plastic cap that screws in with a philips screwdriver. open that up and it will help you get more water into the motor initially.
then drive the car around with a full overflow tank. when the water in the motor heats and expands to a boil, once it cools down it will draw in all the water from the overflow tank. keep doing this till your heater blows hot at idle, or you get no more fluctuation in your overflow tank.

i now have my thermostat out to try and help this process go faster, but it doesn't seem to help much. i am going to make a way to pour water directly into the motor using a couple tubes that will go into the square cap at the top of the motor underneath the plenum. i believe that area is how the factory originally fills the motor. one tube to put water in, and the other as a vent. that will eliminate any air bubbles from the very start. i have gone through this process so many times now, i am fed up, lol.

good luck

Z350Lover

iTrader: (2)

overZealous,

thanks heaps and appreciate for your time to help me out!!! the whole thing works.... and it blows hot air at idle now without any problem! The reservoir tank stays unchanged for the entire trip down to the dealer and they will carry out the check once again today. I just don't get what's the problem with the overheating yesterday though.... possibly some air bubbles in the system to block the coolant going back in? because I remembered that the workshop took off the radiator to install the crank damper pulley... but that was like 2 to 3 weeks ago though...

MIAPLAYA,

I hope it is not the thermostat, but if it does fail, it should be keep on doing that, right? thanx

cheers,

richie

MIAPLAYA

iTrader: (3)

It'll do it intermittenly at first and then when it full blow fails it will just overheat all the time..

gsazabi

iTrader: (51)

Z350LOVER,

I had EXACTLY same thing happen to be before, so I feel your pain.
In my case, I had ECU reflash done at Technosquare and they
forgot to plug the fan connectors back in, causing the car to overheat.

If the installer removed the radiator, there's a very good chance they did
the same thing and forgot to put in back in.

If that is not the problem, my knowledge ends here