It's most likely the regulator which is built into the alt.

 

Well... My alternator just caught on fire. So... that happened... and I think I confirmed the diagnosis.

 

I would not drive with the alternator at overvoltage. The risk of damaging other components is too significant. For example, it would be far less than great if you blew up your battery.

 

I had voltage on the gauge go up on me once. Luckily on a cool night so the high beams went on along with heater wipers fog light etc til I could get home about 30 miles away. Oreilly checked it the next day and sure enough regulator was bad.

 

I changed out the alternator today and it's back to its old self.

Another question came up though. What is the proper way to tighten the alternator belt? I stuck a large screw driver in between the coolant neck/housing/temp sensor area and the alternator then pried it back. The coolant housing started leaking, so I have a feeling that was not the proper thing to do. I tightened up the bolts and it seemed to fix the problem, but it scared me quiet a bit considering what kind of a hassle it is to get to that gasket.

 

Alternator tightening coolant leak. NA cars.

Hi Zack,

I'm afraid to offer that you may NOT have fixed the coolant pipe leak coming off the back of the water pump (water inlet pipe Page Co-6) unless you can verify the "O" ring there is fresh and new.

Expect coolant to drip down the hot block and evaporate AFTER the car has gotten up to temp and the pressure develops in the cooling system. (Won't necessarily leak when parked.)
This will show when you start needing to add coolant to the overflow bottle.

There needs to be "sticky" on what NOT to do in alternator tightening.:angel:
Mister2 Tim

 

I have a device similar to this: http://www.mscdirect.com/product/details/35438209. It is too long to fit between the pulleys but the tube can be trimmed to work perfectly. It was one of the first tools I bought for my MR2 because the alternator housing was cracked from improper tightening techniques.

 

Just there site pops up. Not a particular page

 

 

Cool never seen one of those before

 

Na, all of the gaskets are new. Had to do a headgasket 3K miles ago. So its all new down there. I got under it with a flashlight. Revved the ever-living-crap out of it. Its solid.

Now, if it was the old gaskets, that would be questionable