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Heater Luke Warm / Temps Climbing Quicker


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I had a radiator change with new rap cap in early July and it started overheating when I got it back. It turned out to be an airlock which mechanic cleared and all had been fine for nearly 2 months.


Today the temps were climbing quicker than usual at idle and heater is luke warm. The max it gets at warn idle is just over 90c and the fan kicks in but then stays on it doesn't reduce. The stock temp gauge goes from its usual quarter mark to half way.


Could this be an airlock still or thermostat? Coolant reservoir is full.


My amp has recently started blowing fuses, I'm sure it's not related just thought I'd say!


Car is 06 Rev Up 


Thank you 

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Thanks Davey.


I'm fairly sure the heaters were working after it was re-bled the first time and the fans were definitely kicking and going off once cooled down as normal so it's only happened in the last day or so (car is used daily). Could a small air lock reappear in the system or not be noticed for a while?


One thing I haven't checked is coolant level in radiator but expansion tank is full



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Full expansion tank? Full to line/marker or full to brim? Expansion tank should expand when hot and then reduce when cool/cold - if it's staying pressurised it would suggest head gasket (pressurised by exhaust gasses).



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Just some more info;


Heater is super hot when driving on motorway but gets colder the slower I go and the temps rise.


The aftermarket sensor (cut into top radiator hose) does not seem to be giving correct readings anymore. It goes to max 90c but fan is already on which was not the case before. (Used to come on at 95c. The stock temp gauge also goes to the middle when idle for a while but aftermarket is still at 90c (in theory this should be higher as got to 90c regularly before whilst staying at quarter mark).


Hope this makes sense lol

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6 hours ago, Osakakev said:

Thanks Zalas.


So either still a small airlock or thermostat. Would upgrading the radiator and leaving stock (assume from 2006) thermostat cause this? 

No, shouldn't do. Tstat opens and closes regardless of rad unless you've got something dislodged and stuck in the tstat from the flushing and refilling?

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