Heater core leak

[aussie merc]

for my 2 cents do it right do it once sealers are are just a get you home option often the leak is a warning of bigger issuse that you will need to fix later anyway and often with something of that age you find the air side of the core is clogged or corroded and requires cleaning for it to work effectively .Any good rad shop will be able to repair or even replace the core and tanks if its needed and you think its worthwhile when the cold starts to bite