Hey, got a 86 5ltr tpi an batt died the other night, got it jump started an home, tightened alt.belt as loose an changed batt for a new one, i think batt/voltage gauge is to sit around half way (13v) but its now sittin up at the three quarters mark approx (16ish v) when heaters r full wack or wen idlin it sits around half way, IS IT SAFE 2 DRIVE? i heard it cud go on fire? an i also think i could b the alternator, any help wud b great, thanks, only had the tank a month!!!so keen 2 learn as much as poss cheers, amy

 

Check the battery voltage across the battery terminals with a voltmeter. Turn on all the electricall stuff, lights, defroster, etc.The voltage should hold between 13-14 Volt with the engine revving between 1000 & 3000 RPM. If it drops low the alternator is weak, or the battery could have shorted cell.
Turn all electrical stuff off & repeat test. If voltage goes high, the regulator is bad, or the battery could have an open cell.
If the voltmeter on the instrument panel does not track with the test meter, it could be bad or bad wiring or connection. Also make sure the battery electrolyte level is correct.

 

waw nice n detailed, thanx very much i will do!! dont have a volt reader myself but will get hold of one if regulator is knakered will it need whole new alternator and is it best to get one with a higher amp? x

 

The stock guages on a chevy dash are far from accurate. Has the new battery been holding a charge? If so your battery was probably trashed. Did you know how old it was? Anything after 4 years and they can go with absolutely no notice. If the new battery is holding a charge...ie the car is starting ok...lights working...your alternator/regulator are probably ok.