hiya everyone iv got a mk3 1.3 coupe and the alternator belt went so i replaced that and i also replaced the battery as the other one was flat but aftr running it for about a day it started hissing and about 10 mins later it popped

so i put the original battery on it and its starting to do the same hiss and get very hot

any body got any ideas ?

my brothers a mechanic and he hasnt had a look yet but he thinks its overcharging the batteries ?

Sounds like your diode pack on your alternator's knackered so it's kicking out too many volts. If you dare get near the battery, see what the voltage is with the engine running. More than 14V and you've probably got a problem.

yep i did a quick test and it was 17.5v when running so i went to the scrapper and got another alternator and slapped it on and it running a steady 14.2 does that sound abit better ?