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Overheating issue, potentially bad reservoir cap?

1490 Views 3 Replies 4 Participants Last post by  JTownPBX
So I've had my 2009 jcw for a little over a year and have fixed all the common issues, but just recently it has started overheating, causing it to steam and spray all the coolant out of the reservoir cap. It blew white smoke out of the exhaust before I realized it, but its only after it started to overheat. Could it be head gasket, water pump, or just the fact I need to re-bleed it? I use the right coolant and let it bleed for like 5 to 10ish minutes, any tips?
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Get a sniff test done to see if the head gasket has gone.
My Mini R56 N12 had a similar problem. Having gone through the whole system by testing fuses, relays, thermostat, fan, water pump and the friction drive to the pump I then changed the reservoir cap and everything worked as it should. I still need to check the head gasket to confirm all is well. There are a couple of quick tests you can do:
Check the fuses for the fan (engine fuse panel)
Bleed the cooling system - use the bleed point on the thermostat housing (if your car has this)
Check you have hot air coming from the heater - cold air usually means an air lock
Switch on aircon - does the fan run. Note that the fan will not run if the aircon system is not charged
Remove the connector from thermostat with engine running - fan should start

Hope this helps
White smoke would be a head gasket. In my own opinion. I have a coolant re fill kit that is a coolant system pressure tester that would tell me for certain.
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