HJ 308 water pump and thermostat

yes it may be leaking from them...assuming gasket surfaces good, threads correct, torque right, gasket sealed..I'd be looking carefully for leakage at bolts...Maybe even try some teflon tape?

your welch plugs to make sure one of those isn't leaking if around the sump...it's possible the timing cover gasket ...but the coolant will go all over the place esp with a fan blowing it...it's good if you can pressure test the system when cold as it can highlight leaks well....whats the inlet manifold like? they are prone to leak due to corrosion..also check the water pump bearing tell tale as they can leak from there..I bought a new water pump (Indian) from Repco for a 308 and it leaked from the bearing from brand new...took it back and replaced with a Japanese one and an extra $15 and no leaks...there is a little hole underneath and it drips coolant onto the crank pulley..which can make it look like around the sump..worth checking

I've had a few of those manifolds corrode and leak mainly around the front bolts...I've had them repaired by having them welded and machined which at the time was cheaper than buying a new manifold..and maybe the same price as buying a good second hand one but each time it's been on daily drivers so just needed the job done and no time to look for good used parts..I'm wondering if a product like an alloy repair filler would do the trick..have a look at this vid..https://www.youtube....