2004 Infiniti overheating

Sounds like you still have air bubbles in the coolant system. Did you let the system cycle through when you put in the new thermostat? The heat loss could be due to a bad heater core or it has air bubbles around it, more likely the latter. While you're driving the car, as your coolant system cycles through it will come into contact with those air bubbles causing your engine to overheat. I believe you will see coolant leaking from the water pump if it were bad but it is rare for a water pump on the VQ35 to go bad and quite costly since it is buried pretty deep into the engine. I would suggest bleeding the system again and allowing it to fully cycle through. 1) Empty your coolant system 2) Once empty, screw back in the radiator drain plug 3) Remove the radiator cap 4) Place a funnel that fits firmly into the neck of where the radiator cap was or use a spill proof funnel 5) Pour coolant into the system until the level of coolant in the funnel stays steady at about a 1/4 of the funnel (will expand) 6) Turn on your AC system to the max at high heat (have the actual AC button off, you want the system to blow hot) 7) Start the engine and allow it to reach the nominal temperature 8) Once it reaches nominal temp. rev the engine to 2000-3000 rpms and hold it there anywhere from 10-30 seconds. This will allow the thermostat to open and let any air that may be in the system out. (You will see this in the funnel when it begins to "burp") You are going to rev the engine 2-3 times at those noted timed intervals. 9) Allow your car to idle, and slowly open up the coolant bleeder valve. You should see air bubbles rapidly squeeze out. *Do not fully open the bleeder valve* 10) Repeat the process until you no longer see air bubbles in the funnel, you no longer see air bubbles being squeezed out of your bleeder valve, only fluid and your AC is blowing hot as it should. 11) After you finished, replace the funnel with your radiator cap, check for leaks and take it for a test drive. Watch the temperature gauge. If it fluctuates between HOT and nominal, you still have air in the system. Also, I forgot to mention, you should squeeze the upper and lower main radiator hoses to help your system burp. You can do this during, before and/or after the flush but be careful, the hoses will be hot and depending when you squeeze the hoses, there will be moving parts. It will take awhile, it will be hot and refill your coolant as necessary if it happens to be sucked down from the funnel. If your coolant level looks like it is going to spill over your funnel, shut the engine off and try again once it lowers. Have plenty of rags on hand. Other than that, hope this helps.

Sounds like you still have air bubbles in the coolant system. Did you let the system cycle through when you put in the new thermostat? The heat loss could be due to a bad heater core or it has air bubbles around it, more likely the latter. While you're driving the car, as your coolant system cycles through it will come into contact with those air bubbles causing your engine to overheat. I believe you will see coolant leaking from the water pump if it were bad but it is rare for a water pump on the VQ35 to go bad and quite costly since it is buried pretty deep into the engine. I would suggest bleeding the system again and allowing it to fully cycle through. 1) Empty your coolant system 2) Once empty, screw back in the radiator drain plug 3) Remove the radiator cap 4) Place a funnel that fits firmly into the neck of where the radiator cap was or use a spill proof funnel 5) Pour coolant into the system until the level of coolant in the funnel stays steady at about a 1/4 of the funnel (will expand) 6) Turn on your AC system to the max at high heat (have the actual AC button off, you want the system to blow hot) 7) Start the engine and allow it to reach the nominal temperature 8) Once it reaches nominal temp. rev the engine to 2000-3000 rpms and hold it there anywhere from 10-30 seconds. This will allow the thermostat to open and let any air that may be in the system out. (You will see this in the funnel when it begins to "burp") You are going to rev the engine 2-3 times at those noted timed intervals. 9) Allow your car to idle, and slowly open up the coolant bleeder valve. You should see air bubbles rapidly squeeze out. *Do not fully open the bleeder valve* 10) Repeat the process until you no longer see air bubbles in the funnel, you no longer see air bubbles being squeezed out of your bleeder valve, only fluid and your AC is blowing hot as it should. 11) After you finished, replace the funnel with your radiator cap, check for leaks and take it for a test drive. Watch the temperature gauge. If it fluctuates between HOT and nominal, you still have air in the system. Also, I forgot to mention, you should squeeze the upper and lower main radiator hoses to help your system burp. You can do this during, before and/or after the flush but be careful, the hoses will be hot and depending when you squeeze the hoses, there will be moving parts. It will take awhile, it will be hot and refill your coolant as necessary if it happens to be sucked down from the funnel. If your coolant level looks like it is going to spill over your funnel, shut the engine off and try again once it lowers. Have plenty of rags on hand. Other than that, hope this helps.

Sounds like you still have air bubbles in the coolant system. Did you let the system cycle through when you put in the new thermostat? The heat loss could be due to a bad heater core or it has air bubbles around it, more likely the latter. While you're driving the car, as your coolant system cycles through it will come into contact with those air bubbles causing your engine to overheat. I believe you will see coolant leaking from the water pump if it were bad but it is rare for a water pump on the VQ35 to go bad and quite costly since it is buried pretty deep into the engine. I would suggest bleeding the system again and allowing it to fully cycle through. 1) Empty your coolant system 2) Once empty, screw back in the radiator drain plug 3) Remove the radiator cap 4) Place a funnel that fits firmly into the neck of where the radiator cap was or use a spill proof funnel 5) Pour coolant into the system until the level of coolant in the funnel stays steady at about a 1/4 of the funnel (will expand) 6) Turn on your AC system to the max at high heat (have the actual AC button off, you want the system to blow hot) 7) Start the engine and allow it to reach the nominal temperature 8) Once it reaches nominal temp. rev the engine to 2000-3000 rpms and hold it there anywhere from 10-30 seconds. This will allow the thermostat to open and let any air that may be in the system out. (You will see this in the funnel when it begins to "burp") You are going to rev the engine 2-3 times at those noted timed intervals. 9) Allow your car to idle, and slowly open up the coolant bleeder valve. You should see air bubbles rapidly squeeze out. *Do not fully open the bleeder valve* 10) Repeat the process until you no longer see air bubbles in the funnel, you no longer see air bubbles being squeezed out of your bleeder valve, only fluid and your AC is blowing hot as it should. 11) After you finished, replace the funnel with your radiator cap, check for leaks and take it for a test drive. Watch the temperature gauge. If it fluctuates between HOT and nominal, you still have air in the system. Also, I forgot to mention, you should squeeze the upper and lower main radiator hoses to help your system burp. You can do this during, before and/or after the flush but be careful, the hoses will be hot and depending when you squeeze the hoses, there will be moving parts. It will take awhile, it will be hot and refill your coolant as necessary if it happens to be sucked down from the funnel. If your coolant level looks like it is going to spill over your funnel, shut the engine off and try again once it lowers. Have plenty of rags on hand. Other than that, hope this helps.