That Cylinder is the fuel filter and is a routine service part. dont mend just change cost is about £7
Perhaps slave cylinder, line or fitting leaking?
Because your cylinder head gasket has probably failed or worse you have a cracked cylinder head. first check it is not coming from a nearby hose sometimes if its only a pinhole in the hose it is not always obvious, hope this helps.
Heater core may be leaking Door seal? Windshield seal?
That sounds like a wheel cylinder leaking brake fluid.
your heater core is leaking
is coolant leaking from engine?or is it leaking from water pump and running down engine and appears to leak from engine
No
Antifreeze leaking from the heater core.
your slave cylinder is leaking,need to replace.
most likely heater core leaking
Sounds very much like the cylinder head gasket is leaking allowing compression into the water system. with the radiator cap off bulles will be seen in the water when revving the engine. A garage workshop normally use a sniffer to check for this, not too expensive to have checked.
Passenger side floor? Could be leaking heater core