BigMouse

I think the voltage regulator in my 88 80Q has gone bad. I put a multimeter on the battery and it read 12.6v, perfect. But when I started the engine it shot up to 14.6v, even peaked as high as 15.2v. After the engine warmed up, I noticed the RPMs would drop about a hundred for a few seconds, during which time the mulimeter would go haywire. If this is the voltage regulator, does it require replacement of the entire alternator, or can the regulator itself be replaced? How much would either option cost (ballpark). Thanks a lot.

SiV6Qcoupe

I had to replace my alternator due to some internal fault in the unit - it suddenly started to discharge my battery VERY rapidly.
You can buy the voltage regulator separately or just the alternator or both as a unit but quite expensive items. I opted for a used but younger alternator from an Audi used parts dealer for a lot lot less.
I have a voltage dial in my car and it does as you describe upon startup but holds a constant voltage above 12v when the engine reaches normal idle speed. Have you tried measureing the voltage at the voltage regulator terminals?

BigMouse

May try testing that today. Thanks.