Hi all, I was doing my annual coolant change, vacuum fill etc. Then came the time to bleed/purge the system of air (using a reservoir) and all was going well, little air bubbles were coming through until the car reached normal operating temp. Then the coolant was getting pushed up into the reservoir and overflowing and quite quickly too, first thought was to cut the engine and as I did the coolant was sucked back into the system, I have tried to re do the bleed but it happened again, up to running temp and coolant overflows, not sure what is happening, any help or thoughts as usual would be greatly appreciated.
You’re not supposed to bleed the system by letting it warm up without a coolant reservoir cap.