Laura Fletcher

Today my car engine started to rattle when pressing on the accelerator. I stopped the car to have a look. At his point i could also smell burning oil and a bit of smoke was coming from under the bonnet. I realised the engine must have been over heating so checked my coolant amount. Now I had topped up my coolant about 3 weeks ago, yet on checking this i found it completely drained. Nothing in it. So obviously engine had overheated. Now i drive an R reg Ford KA. Filling p the coolant tank i saw that it was just being guzzled, so checking over the inside of my bonnet i noticed a pipe was loose. Now i had to to fill the coolant tank with water, and on doing this i noticed it was just coming out of this hole where i assume the pipe is. Seems i am missing a part for the pipe to stick onto, the other pipe next to it is fine.
This is such a pain, just want to know what item i need to fix this. Help would be appreciated very quickly
thanks

Added:
Also car was fine when picking partner up from work and dropping him off home, straight after this i was on my way to my own work when the problem started.