wow... i've never heard of the 5m being notorious for blowing head gaskets
the engine most refer to when speaking of the bhg syndrome is the 7M series engine and this is due to incorrect torque settings on the bolts... they were originally torqued to 58 where they actually need 72
if you have had the proper machine work done on head and block, new gasket, new bolts and you keep blowing them there is something else wrong
where on the gasket is it blowing?
how do you determine the hg has gone?
oil/water mix?
overheating?
give us a quick run down of the symptoms and your findings and i'll see if i can come up with something new
