Coolant leak at rear of engine

a leaking rear heat coolant line/hose.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

It is not a blockage if coolant is leaking. Determine if the core itself is leaking or a loose hose clamp. Repair as necessary. Don't ignore it since running the engine pressurizes the hoses and will push out coolant causing engine overheating.

why not find source>?/???? is this a stick or A/T?
a hot engine, has 12 psi AF coolant pressure.
and any leak is easy to find.
it will even squirt at that large pressure if bad.
i cant be more help due to you not stating which engine option.
8v or 16valves.
ill roll the dice, and pick 16v, and
the rear of head has main water, fitting that leaks. (housing)
or
the heater hoses leak
or the cars heater core leaks
and it finds a way out of heater box, to A/C condensate tube under car and leaks.
or the floor boards are rusty and AF leaks there, from same core leak.

are the passengers (USA LHD) toes green with AF?

Square plate on rear of head with rubber hose attached in middle ck hose and for best results replace gasket on plate.

Most of the time when I see coolant leaking at the rear/top of the 3400 engine, beneath the throttle plate area, it's usually coming from the intake gaskets. There is a coolant cross-over passage at the rear of both heads and as time passes the gasket will sometimes split along the sides of this passage and coolant will begin to leak out. It can be tough to see clearly whats going on in this area well enough to pinpoint the exact source of the leak so it may take a bit of time to find it. Often with an intake gasket leak the coolant will puddle on top of the block then drip down the rear side of the engine and drip off of the pan or transmission bell housing. Hope this helps you find your problem!

Commonly known as a frost plug / welch plug, If its the rear one then yes the trans has to come out. make sure the garage fits a brass one as they do not corrode.

depends on whether its leaking coolant or air, since both run through intake. if leaking coolant, you will see coolant leaking from either the front or rear of the intake itself. it can also leak into the engine, causing coolant to mix with the oil. if its leaking air, usually a small leak will present more when the engine is cold, with rough running or high idle. a large leak will run rough all the time, but should be able to hear air hissing if large enough. a vacuum leak from the intake will sometimes present as a check engine light, with codes p0171 and/or p0172, depending on whether the leak is on one side or both.

if your coolant leaks eventually you will run out of coolant and your engine yes will overheat

If the leak is in the rear of the engine, there are several things that can cause the leak. Intake manifold gasket, heater hoses, heater core.........
If this is a small leak, you might try a can of Bars Leak. It should stop any component coolant leak, however, it will not cure a heater hose coolant leak.
If you try the bars leak, give it 50 to 100 miles to stop the leak.
If it is a large coolant leak, it is best to have the leak identified and repaired, much cheaper in the long run if you are planning on keeping the car.
Let me know.
Regards,

My coolant leaked out and on top there is a large hard plastic container, I had to replace it, that stopped my coolant leak.