I have a 1990 Cooper so 1275cc Carb engine which recently drank its coolant, I had hoped head gasket but on stripping back it was fine but a steel ruler on the head showed light through.
I had the head skimmed and then I rebuilt (i'm not a mechanic so just a Haynes manual follower) and all appeared ok in the garage and on a quick run for MOT but a longer run straight after left me with coolant dripping from the underside of the bonnet.
Running back up in the garage later after cleaning everything down I could see coolant from between 1 and 3 studs at the front between block and head and wondered if the first run had shifted anything so thought I should check all the torques. The nut on stud one just turned freely as did three but all the rest click on the wrench as I expected.
Pulling the two studs out they look fine, no damage on the threads, they were in the right way around as well! When I try to put them in again they just turn freely, I cant pull them back out upwards, I have to unwind them, so they are biting on something but that might be the gasket. After taking number one back out again to show a garage it has a nice spiral of cast iron in the thread, not a helicoil but they feel the thread in the block has failed.
Long description sorry, question is if the block thread has gone has anyone any experience of fixing this, can it be done with Helicoils and is this a home garage job or is it engine out on and a bench essential? There seem to be lots of kits for UNC 3/8" Helicoils but don't want to start if I'm just going to damage the block further.
Any advice would be great. Martin