Sounds more and more like a sensor. If you had air in the coolant I'd expect the heater to be acting up. Likewise if the thermostat was faulty. I misread your original post and interpreted it as coolant over temp.
coolant light on/off.
- Thread starter ben g
- Start date
i would fill it so you can see the water then do a couple of long high rev runs let it settle then check it the next day, it seems on mine after lots of high revs the water was dropping and the light coming on. I thought the worst head gasket but turns out to be a tiny crack in the expansion tank which gushes more water when the engine is worked hard and only when warmed up fully. Short runs /cold / low engine revs there is only a tiny amount of leakage so takes weeks to get the level to drop.
I m having a similar problem. I have a 2008 Z4 I recentally purchased and while checking the fluids I didn't close the radiator cap correctly. Next day all coolant is on the ground and I presume it's a broken hose or expansion tank but after inspection no hose or leaks are apparent. I bleed the radiator and put new antifreeze conclude the cap wasn't sealed correctly. I drive the day after and the low coolant light is turning of and off on occasion and I've already topped off the radiator. So I again look for leaks and none are apparent so I have no clue why the light turns on then off
Genuine BMW (isn't bad value as it can be diluted with tap water within hardness limits) or G48. There is a long list of approved but I've only seen the G48 here in the UK.z4dan said:
OE concentrate was cheaper than G48 ready mixed.