Toyota Repair: voltage problems, diesel questions, volt amp

Question
I have an 84 landcruiser sta. wag. diesel.  I noticed it was getting hard to start and voltage drew down low on starting and then would go high (14v) on driving.  Dash lites would pulse a bit at night.  On idle the charge lite and filter warning lite would come on.  I replaced both batteries, cleaned wires and checked contacts.  Problem still existed and after a while the glow plugs stopped working and became dificult to start even when warm.  I checked brushes and they are fine.  I replaced the voltage regulator and that seemed to fix most things.  The glow plugs work fine now and the dash lites dont pulse any more.  Readings off of the battery are all 13.5 volts.  The only thing I notice now is the voltage meter goes up to approaching 16 v. while driving.  At idle it goes down to 12.5 v.  Even with heater, headlites, and driving lites on the voltage stays up around 15 v. Prior to all this problems the voltage would go up a bit on driving maybe to 14v. and settle in around 12v. on idle.  This 16 v. showing on the guage concerns me.  Do you have any advice.  Thanks in advance. Rick

Answer
I normally don't answer diesel questions because they are not sold here in the US and I have no training on this model, your question seems to be a generic one concerning a possible overcharching condition, I recommend having a toyota dealer or another repair shop check the actual alternator output by hooking a volt/amp meter to the battery, if the alternator is charging at a voltage of more than 14volts there is a problem, the meter on the dash may not be accurate so have the alternator checked.