I had this very same issue...lgayuchan wrote: ↑Wed Nov 15, 2023 10:13 pm I have QQ+2 2013 having problem with coolant decreasing. Approx 100 ml top up for roughly 20 miles run. I took to a garage but they could not find any leak anywhere, oil ok, no white smoke on tail pipe, pressure test is ok so was advise to continue using it and bring it back if loosing coolant continues. It was due for its yearly service in a months time so I book in to my local garage(another garage). My car then had its service and told them about the issue of still loosing coolant, has topped up more than a liter of genuine Nissan coolant and run about 150 miles. I was told thermostat might be the problem so was changed. Have to bring the car back to the garage as still loosing coolant another checks done but couldn’t find any faults, they suggested K seal or steel seal even if it passed the pressure test so I opt out for the more expensive one which is the steel seal hoping it will magically resolve the problem. Went to work and overheated on the motorway, breakdown called and brought to the Nissan Garage. I was told they could not find any leak and thermostat is faulty maybe due to steel seal so was replaced, cooling system was flushed to get rid of remaining steel seal. Car was test drive and said ok. Have to bring the car back to Nissan after a day with same reason of loosing coolant and coolant reservoir getting too hot with only a 10 minute short drive approx 3 miles. One more thing I noticed is that coolant level goes down below the minimum level after I run the car and when I opened reservoir cap after it cools down, there was air pressure being released and a bit of coolant fills up the reservoir to a level just above the minimum level. Now Nissan suggested replacing the radiator as it might have clogged up by the steel seal which I agreed as well as re flushing the cooling system for the second time. I was called to go and Collect the car as it was all sorted. To my disbelief it did not and now another issue has popped up! Car heater is not blowing hot maybe just slight warm after 12 miles - 15 minutes run. If I had known this problem I would have opt out onto looking for a newer one. I am stuck because I have spent a lot of un budgeted money to this car for changing major parts like suspension arms, brakes & discs, tyres and it all happened this year. Sorry for the long story, I just hope I can find similar issues in this forum and they have it resolved.
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Suspect radiator hoses were ballooning up, dropping the coolant level enough to introduce air into the system causing an impossible to diagnose air lock, but also check your intake pipes post turbo as I was loosing coolant too and suspect it was from the turbo
