Hello everyone,

I have a 2005 G35x with 131k miles.
Since last winter, it has been unable to produce heat at idle.
Rev above 2.3k rpm, then comes heat.
Engine does not overheat even at duress.

At first I thought it was a bubble in the coolant system, but after many tries to get the bubble out myself, and even paying a shop to do it, it's been unsuccessful.
The shop is suggesting that the water pump may be bad.
Strange thing is that I don't have a coolant leak.

Is it possible for the water pump to be bad without a coolant leak?
Thanks.

 

I'm not doubting you or the shop but our cars are notoriously hard to bleed completely. Did you replace the radiator or coolant lately? When the engine's fully warmed up are both the upper and lower radiator hoses hot as hell? It's still possible you have an air bubble but other possibilities are the pump is bad, the thermostat is bad or the heater core is clogged.......

GL and let us know how it turns out.

 

Thanks for the tip. But if thermostat was bad wouldn't it take forever for the engine to warm up? Because that is not the case. I have completed considered the heat core being clogged but the heat comes out easily as long as engine is revving past 2.3k rpm, so I doubt it.
I'm just curious if anybody ever experienced a bad water pump without any leak.
​​​​​​edit: After a more closer observation, all the engine needs is 1.5k+ rpm to start pumping out heat from the heater core.
It's just really annoying because just few seconds after coming to a stop at like a stoplight or something, it will start pumping cool air.

 

Anything is possible!

So an entire year has gone by and in all of that time you neither read the troubleshooting steps in the FSM nor consulted an Infiniti dealer that most likely would have discovered that you have an air pocket in your cooling system?

Using unqualified shops by going cheap generally results in paying twice.
What you should have done is taken your vehicle to a dealer and if the original shop performed perfunctory work on your vehicle, all it requires for you to request a charge-back on your credit card is written documentation from the dealer that you send to your credit card company.

http://www.nicoclub.com/service-manu...5_G35_Sedan/co

http://www.nicoclub.com/service-manu..._G35_Sedan/atc

See page ATC 103

If you do not have the necessary skills to find and locate the root cause on an almost 12 year old vehicle, just take to an Infiniti dealer and tell them to JUST FIX IT.

Good luck

Telcoman