2014 Q60, 73k miles. No coolant leaks ever detected, all hoses replaced. Long term problem. Radiator full, reservoir full, but the radiator will not draw coolant as needed from reservoir. It just gets low on coolant, about a quart over 10,000 miles. Reservoir still full. Please advise.

 

I'm assuming you are running the 3.7 (VQ37VHR) which is why you posted here on a G37 forum (2009-2014 G37 shares the same motor)?

If yes, you likely have air trapped in the coolant system. You can use a Lisle Spill Free Funnel to bleed the air.

If you are running the VR30 TT, I'm not sure as the coolant system is much more complicated on that platform.

 

Just a quick note for clarification, the 2014 and 2015 Q60 are the same car as the G37 coupe, bascially a re-badged G37 coupe. The redesign and different engines didnt hit the coupes until 2016.

 

Thanks for the clarification beefy. I knew about the 2014 Q40 being a rebadged G37 Journey sedan, but I thought the coupe led the sedan in the transition to the Q platform (I believe that's what happened with the G37). Things you learn here on the community.

 

Replace your radiator cap

 

@thescreensavers beat me to it. If the level in the overflow reservoir never changes, then either the overflow hose is clogged/ kinked or the radiator cap is not operating as it should.

Infiniti's idiotic nomenclature notwithstanding, the principles of liquid expansion are universal. In this closed system, as coolant heats up it expands and pressure increases. As this pressure increases it has to be released. If the cap is not venting to the reservoir then the coolant is leaking out of the system elsewhere, albeit a minimal amount. Conversely, as coolant cools, it contracts thus creating a vacuum. Again, if the cap is not allowing the system to draw from the reservoir to equalize the pressure, air will be introduced into the system.

Replace the radiator cap (p/n: 21430-8999C), top off and bleed the system and go from there. A new OEM cap should run ≈$20.

As far as the Q's go, 2016 was the transitionary year for the Coupe to the CV37 platform. Not that it matters as the Q60 is officially dead anyway, the Q50 is on life support, and I doubt Infiniti even knows how or if the other Q'soup models will endure during this latest identity crisis.

 

2014 Q60 same as 2013 G37 coupe FYI. Used Lisle funnel to purge air from coolant system. It took around an hour. Notice that coolant level rose about an inch above the funnel mark made before engine was started before the air was released and the level returned to the mark on the funnel. At peak heat observed 200° on upper hose and 215° on lower hose. When engine was shut off, level on funnel rose slightly before I was able to disconnect funnel and reinstall radiator cap. Hope this resolved problem. Thanks for everyone's help.

 

Well stated. As someone that has been with the brand for nearly 2 decades, it's a tough pill to swallow. I really want to like the Q, but it seems like a great motor paired with a series of mis-matched sub-systems.

 

After purging air from the coolant system, the vacuum issue was resolved. The problem remains though. I am losing around 14 oz of coolant per month. The upper and lower hoses have been changed, along with the radiator and reservoir cap in effort to resolve. There are no visible leaks, and never anything on the floor in the garage where it is parked. Not sure what is next and am open to suggestions, please.

 

Did you change out the heater core hose union?

I would get coolant dye and then go hunting

 

If your car is losing ≈14oz. of coolant per month then you have a leak somewhere. As coolant heats up the fluid gets thinner, therefore, even the tiniest of leaks might not show up on the floor as it would evaporate before it hit the ground.

Either get some coolant dye or get a pressure test and start hunting. Check around all hose connections, clamps, ports, the radiator and behind the AC compressor (water pump weep hole) for any traces of green (or blue) dried out coolant.

If you go the dye route, it would not hurt to check your oil for any traces of dye/ coolant- in the unlikely event that you have a failing head gasket or water pump seal.

 

Dare I mention ordering an oil analysis through Blackstone? I believe head gasket leaks show up as increases in sodium/potassium? One of those situations where you need to be careful what you ask for, which is why I'm hesitant to order one for my son's Ford Ranger with almost 200K miles.