mmm come across something.
now when I removed the customized alternator bracket from the union, it was held down on one side with 2 bolts. The union has 4 bolts in total.
The 2 left bolts were new longer ones for the the bracket. I first removed one of the original ones to measure the length in order to buy new ones for the right side.
One of the original ones had teflon tape around it!!!
Ok so I carried on and removed the bracket and replaced the 2 bolts on the right side after removing the bracket (in the process I lost just a small amount of coolant as it leaked slightly under the gasket due to 2 bolts being removed).
Tightened everything up and tested. No leakage of coolant from the gasket, so all was fine.
But recently I noticed a small leakage of coolant from the top of the bolt (right hand side, original bolt that had the teflon tape!!).
I removed this one bolt last night and quite a bit of coolant oozed out of the bolt slot on top of the union!!!
So I'm assuming the gasket around the base of this one bolt hole is not sealed properly hence the old teflon tape. An old mechanic must have put this on. The other bolts were fine, no oozing.
I replaced the bolt with new teflon tape for a temp. fix. as replacing this gasket involves quite a bit of work.
Also engine ran quite hot the other day even thought the level of coolant was still ok.
Think a change of coolant is in order and maybe a flush (including a new gasket on the union?)