Hi, I’m new to this site and heard I could possibly get an idea or answers as to why my 2012 g37 (sedan) is still overheating after I changed the thermostat, the radiator and also the water pump. Currently my car doesn’t have the thermostat, only the housing. I got a new water pump about 5 months ago and it was running good for like 3months and then it started overheating again every time I am stopped at heavy traffic. Once I start driving again, the thermostat will start going down as long as I’m driving it no lower then about 35mph. It would run out of coolant about every 3 days so I would fill it up again.. it’s been like that for the past 2 months or so... but today I noticed that it didn’t even need coolant. It would just heat up when I would be stuck in traffic and once again, the thermostat would go down once I start driving.

 

Where is the coolant going? Do you have a leak, or is it getting into the combustion chamber and leaving via the exhaust? If the exhaust steamy? Does it smell of coolant?

 

Hi! Thanks for replying.. I don’t have a leak, and sometimes the front of the car smells like coolant, sometimes I can smell the coolant inside the car when I’m driving. I don’t really smell it in the exhaust. To be honest it’s hard to tell because sometimes the whole car smells like coolant from the outside but mainly I smell it coming from the front. When I put coolant, it takes about 1qt or 2. Sometimes about half the gallon of coolant.

 

I had a coolant leak this past summer. It was hard to find, but I found it on the back of the engine on the passenger side near the firewall. Basically between the winshield and the engine on the passenger side one of the hose connections had a small leak.

 

You have a coolant leak. Try and find the leak. Would recommend taking off the undertray and letting it drip to pin point it better.

 

Mornin'. I also speculate that you have a coolant leak along with the previous posters. It seems like these cars have that issue. The mechanics noticed my G was leaking coolant and after a full diagnosis recommended to replaced the corroded hoses. It cost me about $400 or so in parts and labor. The service advisor also told me he needed to have his replaced when his car reached higher mileage. Hope this helps.

 

Go rent/buy a pressure test kit for the cooling system. That will reveal where the leak is pretty quickly. It's common for the plastic connector at the back of the heater hoses to fail and leak near the firewall. Z1 sells a metal replacement that also integrates a bleeder valve to make it easy to bleed the system. Also check the hoses going to the coolant overflow tank. I've had one of those crack and dryrot on my car before.

 

If there's not a huge plume of white smoke coming out of your exhaust you just have a leak. Take the recommendations of the previous replies to find where it's coming from.

Make sure you bleed the air out of the system or you'll still have issues overheating. VQ's HATE any air pockets in their cooling systems.