Originally Posted by
ricky_2006
common problem for the st170 as you know prone to leaking.
alot of people say they have issues just getting hold of 0-ring. ford try and sell you whole kit.
as you also know its normally just seal (O-RING) that needs replacing.
is this the bad boy
http://www.fordpartsuk.com/shop/focu...d_seal_852.htm
No that is the seal inside the thermostat housing. You need this Focus RS Thermostat/Block Seal from this link posted above
http://www.carpartsexpress.co.uk/RS-...49-53-710-374/
When i tried to do mine i only found out ford gave me the wrong o-ring when i had everything in bits and on the mondeo one of the bolts is a total c*nt to reach, was not happy so ended up sealing mine up with the old one and some gasket paste.
The thermostat housing are prone to cracking also.