seems the welsh plug has let go behind the head. it sprung a leak when last on a dyno but got repaired (not replaced just something put into the water to block it up) what is best way to replace this plug? pull head off or just take fan and radiator out and move engine forward so i can get to it. or maybe someone has another option. any help would be appreciated.

i would think the best way would be to pull the head off, sliding the engine forward sounds like a sh!t of a job.

Which one exactly? There are 3 on the back of the motor. 2 coolant welsh plugs and one (big one) behind the cam... There is very little room behind the motor to try and get it out, so more than likely the motor will need to come out. And do every other one while its out. Can do it yourself pretty easy... Just get a welsh plug kit and change them all over...

anyone know what it would cost to get the welsh plugs replaced by a shop. i dont have the set up here to be ripping motors out etc..

Be over $500 easy... Its near on a full days job

got quoted 400 earlier. but i know the guy pretty well. so i guess it's pretty good price.

Do it on the weekend with him then... see what he says there... get him to order the welsh plugs (theres about 10 or so 30mm plugs, 1 50mm, 1 35mm and I think 6 19mm[i think that was the size of the small ones)