Hyundai coupe 2006.
I tried to recharge a deeply dead battery by attaching jump wires from donor car directly to terminals of isolated battery(not in car).
I kept the donor car constant at 4000rpm for about 8 minutes, the latter few minutes in which I could smell something burning.
Went over to the hood and saw coolant leaking out of radiator cap and spilling out of overflow tank aswell and falling onto wires. Didn’t look at temp gauge yet.
Switched everything off and then on again after 5 minutes and noticed temp gauge was well past middle but not in red. However it could very well have been in red from earlier.
What happened exactly? Was it that keeping it on 4000 rpm for 5 minutes caused overheating and this had nothing to do with the connected battery, or did battery have something to do with it?
How did the coolant get past the radiator cap, can overheating damage to the cap and make it leak?
I suppose I just need to replace coolant, coolant cap and possibly burnt wires but other than that do you think any engine damage occurred?
I also saw steam coming up from where the coolant was dropping(onto wires). Would this mean the wires were burning? I didn’t want to go to close at the time.
On the bright side battery went from 2.5 volts to 11.66 volts In the 8 minutes. Does that mean it has been recharging or is capable of being recharged or is it still dead as was before?