alternator at 18 Volts???

[jsmith]

brought my car in for a fluctuating idle , my tech says that the alternator is cranking out 18volts and he needs to change it just to start (also thinks that may be the cause). alternator + overvoltage relay + labor = $500. first of all, 18 volts IS out of whack right??? i do trust my guy but thought i'd check with old reliable techs here...

[boneheaddoctor]

Check your battery ground cable make sure its tight and clean.....

if not you need a new regulator...

THe alternator can and will deliver 18v if the regulator is bad.....thats from personal experience. And 18v will do a lot of very bad things to the electronics in the car.

[JerryWagner]

That is correct, the price is about right for a shop to do the work, get it fixed ASAP

[jsmith]

does it mean the alternator needs changing too though?

[Arthur Dalton]

Lot cheaper to change the regulator and lot less labor, as you do not even have to take the alt off.. If the alt is capable of 18v output , it is a decent alt, but the output is just not being regulated.
As far as OVP goes , the high V may have just blown the fuse on top of it..might want to check that before changing that part too.

.. not saying they are wromg, just advising you look at these first...

Arthur is exactly right on this. A voltage regulator can be had for less than $20 and is all you need in this case. It can be changed in 10 minutes.

Good luck,