I have a 2013 G37S coupe that was over heating due to water pump. I replaced the water pump and thermostat and did a pressure test with no leak. After car is running for a while it will start over heating still however if I rev the RPMs it will cool off immediately. No water in oil and it's not smoking. Could my coolant line or radiator have something obstructing it? Had Infinity tech burp the air out of the coolant and finally say he has no idea! Has anyone had this issue and if so, did you get it resolved? Not sure where to go from here. Engine has 198,000 highway miles car was not ran hot for long and has been babied most of it's milage.

 

The Infiniti tech couldn't offer any guidance? Is the thermostat opening (you can feel in the hose when it opens)? Electric fans engaging? What is the coolant temp as observed via OBD? I believe the thermostat opens at 180F and normal operating range is between 180-Low 200s F.

I believe the pressure check rules out the radiator as the culprit correct?

Most of these mysterious overheating issues I have seen are related to people not bleeding the air correctly as the coolant system in this car is super sensitive to air pockets and you need to bleed from the highest point in the system. Then wait patiently for all the small air bubbles to dissapear (I use a spill free funnel, heater on high with fans blowing, wait at least 20 mins while car is running).