Many thanks for all suggestions. Latest is oem w pump fitted and still cannot get any real constant water flow, cold or hot. This is getting interesting, engine full of water with top hose lifted off of metal up pipe. On starting there is mostly NO water flow out of it at any rpm when cold or...

Guys, really not the pumping meaning the impeler is sound. Will pick OEM unit tomorrow to compare non oem and OEM (£251.00 !!!!!). will report tomorrow.

Many thanks for input; checked water flow rate with hose pipe through pipe that goes to heater in matrix, water flowed through block and out of each side of pump (each bank) fixing (pump was off of engine), put hose pipe through top hose connection to engine same result all good with no sludge...

Many thanks but all is good on that front, I am going to take the pump off and try and check the water flow in the block, I have previously used a "seal head gasket/cracked blocks" solution but it appears not to have bunged things up. Further investigations carrying on.

What was the cost of the short engine ? I guess there are no other routes to get orignial block repaired ? Could you comment todays repy (mine) please.

OK, thanks for further info. However did fit water pump back on and only filled the engine with water by way as a test to see if there was water movement when the engine was running; there wasn't. I.E I disconnected the heater hose in the engine compartment point and left open and pointed it...

Many thanks to you both, I will do further investigation this weekend. Seems a shame to scrap the vehicle if it is a cracked block, as most everything works well !!

Thanks and understood about cracked block, so water movement is through the block and down to the Thermo stat via a smaller dia hose, similar to the heater hoses ?

Had vehicle (1996, 70K miles original) for 1 year so quite familier with 4.6 overheating issues. Currently vehicle off road due recent extreme overheating problems, no oil in water, no hose leaks, losing water out of header tank when hot, no bubbles when just started cold. Replaced thermo stat...