It started 2 days ago when I drove my G to work and when i arrived i noticed that the coolant temp is going up and the fan isnt working on its high speed to cool the engine down , so i cooled the engine with our dyno fans and when it got cold checked the water level (it lost a bit) so I added more and started the car and after 10 mins(only idle) the temp went up again...
I tried and removed the coolant temp sensor and then the fans started to work on their full speed so the fans are fine.
I changed the coolant temp sensor (as i had an extra one here)
removed the thermostat and made it direct but still the engine gets overheated.
there is no sign of bad head gasket even...

Now I drive the car with the coolant temp sensor removed and with no thermostat so the fans work on their full speed and temp is low even if I go hard on the car,

Did anyone experience something like this before ?
could there be some kind of switch/speed switch for the fans that i need to replace ? if there is where is it located.


Thanks

 

my car was overheating and it was because of the head gasket and the thing that caused that damaged gasket was that the water pump was internally leaking so didn't produce enough pressure for the cooling system... just for you to make sure do this little test...
start you car then turn on the AC then put to heater to the max if hot air is coming out from AC vents then good news man the problem is some where else...

 

I tried your test with ac and heater it worked just fine,

I brought my friend's G and swapped that control unit for fans, it was working fine.
I put back the thermostat and again overheating... !
the problem surely is from head gasket as everything else is just fine,
I will change the gasket and also ill put a new water pump
I think my water pump caused all this....

Btw, I want to remove my radiator to do a cleaning and pressure checking service but it seems that the AC is attached to it, did anyone ever service theirs ? shall i remove them both and do a service ?

 

How hot are we talking about? Do you have a pic of the coolant temp gauge when it's hot?
Does it overheat when you are cruising on the highway or only in slow traffic and idle?

 

The coolant water was boiling and coming out of one pipe (the pipe which is located between two fans)
I didnt get any picture of the temp gauge because from that day on I didnt drive the car, but it was coming up to somewhere about mid in the gauge.
I connected the car to Cipher and temp was about 115 C.

First day the temp went up after I slowed down and stopped but the last day i drove it while idling and cruising the temp was high so I didnt drive the car from that time.

The problem should be from the head gasket (with/without water pump) so im gonna change both.

I talked to the nissan/infiniti's repairing supervisor and he was like no we wont change the head gasket, we will change the head completely !

So Im taking the car to my friend's garage to change the gasket and water pump

 

a friend had the same problem and the car is running fine, it was just the head gasket and the water pump, also in UAE

he got the car fixed at peak performance in al qouz, Dubai.

heres a thread he made on our club forum
http://www.gtz-uae.com//showthread.p...is-overheating