i decided to flush out my rad last week but have found that if i drive her hard i loose boost and i get a fizzing sound from the rad cap and water pouring out the front passengers side approx where the intercooler is. now i took of the bottom hose stuck a hose in the top and flushed through, then i took off the air release thingy and filled her back up with rad flush. the followed same procedure and filled her up with water and antifreeze. do i need to run the engine when i flushing at any stage.

the best way I have found to flush the rad is to take the thermostat out. If you leaver it in, and flush with cold water, it never opens and so you are not flushing the whole system. Also I do run the engine while re-filling, I find that it clears air pockets better.

 

it sounds like you have a big air pocket, which is expanding when she heats up, pushing water into the expansion tank, which is then in turn overflowing. There is a hole in the neck of the reserve tank, which will p1ss water if it becomes overfilled, making it seem like you have a leak.

wheres the thermostat located

there are two silver metal pipes which join onto the top and bottom rad hoses on the engine block, the bottom one (arrowed in the pic) comes off and the thermostat is underneath it. It is held on by 2 nuts (13mm) on the bottom and an allen bolt(4 or 6 mm, long reach)between the two pipes if I remember correctly. Be careful on the allen bolt between the two pipes, there are two allen bolts in there, one for the top pipe and one for the bottom.

You can refill the engine without taking out the thermostat, make sure you have the interior heater on hot, remove the bleed screw, raise the car on the driver side and run the engine while refilling. Whenever you take it out for a run let it cool down and see if it needs topping up, is your reservoir full up as well?

mark he was talkking about flushing rather than just refilling bud

I missed out a crucial first sentence.

 

I think he has an air lock, that is why I think he needs to follow the above procedure to get rid of it.