Annoying water/coolant loss

[polinsteve]

Just thinking off the top of my head, (I have no knowledge of the V6). A few things spring to mind. Why were the head gasket(s) and water pump changed, because of a leakage problem? Were the heads skimmed? Could it be a crack in one of the bores allowing cylinder compression to enter the water jacket, if this was the case it could possibly only be a problem with the engine hot and running.

[pieterm]

Originally Posted by SD1too

I do Pieter yes. I'm crossing my fingers for you.

Simon

Thank you Simon. I'll let you know how I go.
Pieter

[pieterm]

Originally Posted by polinsteve

Just thinking off the top of my head, (I have no knowledge of the V6). A few things spring to mind. Why were the head gasket(s) and water pump changed, because of a leakage problem? Were the heads skimmed? Could it be a crack in one of the bores allowing cylinder compression to enter the water jacket, if this was the case it could possibly only be a problem with the engine hot and running.

It had a very minor head gasket leak but due to it's otherwise immaculate condition (cosmetically), I decided to bite the bullet and do a full mechanical restoration. With this annoying water issue I'm wondering if I should have left it as it was LOL Everything checks out otherwise - compressions normal, pressure test of water/coolant keeps pressure. Evertything normal except foe this annoying leak.

[pieterm]

Originally Posted by dave lincs

Hi just had a read of this thread on your leak have you had a look in the v of the engine around the thermostat area and pipes? The problem is definitely not air in the system as you have been topping it up regularly another possible leak could be from the bleed screw under the throttle body

Dave

Thanks Dave. Will check this out too. Remember, though, the system holds it's pressure for a considerable time under a pressure test
Pieter

[genpk]

Ive been down this rabbit hole before.
Had thr exact same issue on a couple of my 75s.
Check list-some already mentioned
Radiator- leaks where the radiator core is attached to the nylon tank,usually up where the top hose ataches to the radiator and runs down the side.
Leaks around the nylon elbow which attached the top hose-o ring
Metal coolant pipe under radiator-corrodes
Thermostat housing-nylon cracks and o ring leaks
Intake manifold gaskets seal- can leak internally- no visible leak
Water pump seal- hard to see as dribbles down behind pulleys
Rear head cover plates- there are two small alluminium cover plates on each corner of the rear head.they have gaskets which can rot, also had the whole plate rot-runs down the rear of the engine and evaporates.
Oil cooler pipes
Radiator cap

[pieterm]

Originally Posted by genpk

Ive been down this rabbit hole before.
Had thr exact same issue on a couple of my 75s.
Check list-some already mentioned
Radiator- leaks where the radiator core is attached to the nylon tank,usually up where the top hose ataches to the radiator and runs down the side.
Leaks around the nylon elbow which attached the top hose-o ring
Metal coolant pipe under radiator-corrodes
Thermostat housing-nylon cracks and o ring leaks
Intake manifold gaskets seal- can leak internally- no visible leak
Water pump seal- hard to see as dribbles down behind pulleys
Rear head cover plates- there are two small alluminium cover plates on each corner of the rear head.they have gaskets which can rot, also had the whole plate rot-runs down the rear of the engine and evaporates.
Oil cooler pipes
Radiator cap

Thanks very much for suggestions. Very helpful. Did you also have the same pressure test result? In my case, the pressure test stays stable suggesting no leaks in system - bringing the radiator cap into question ... but I have three new different brand radiator caps and none of them fix the problem.

[pieterm]

UPDATE: Several months later ... the leak was (eventually) found to be at the connection of one of the heater hoses. It was little more than a dribble meaning it did not show up on the standard pressure test ... but if left overnight it did show a very very small pressure drop. Thank you everyone for your help and advice. Very much appreciate it.