TW is using coolant

[cooperplace]

It still uses about 500mls coolant every second day. So far:
-new radiator, hoses, cap, thermostat;
-overflow bottle and tube to it are fine;
-no leak onto passenger side carpet;
-no milkshake in oil;
-cylinder head test (for carbon monoxide in coolant) is negative; test solution instantly turned yellow on exposure to exhaust, so a good positive control for the test;
-gas converter has been bypassed, so running on petrol only;
-no coolant leaks are evident on pressure test.

The engine runs beautifully.

It had a new water pump about 18 months ago when the timing belt was done. I guess the next thing is to use the UV coolant dye. Any suggestions? if anyone know where these things can leak coolant, please advise. it used to go years without using a drop.

The magna right now is giving me the sh1ts. The back seat got stuck in down position, and while I fixed that, it now makes a shriek, like fingernails on a blackboard, over every bump. I put oil on the LHS hinge which fixed the problem for about a minute.

it would be a pity to get rid of it over these minor issues.