The alternator went bad in my Volvo 850 so I replaced it. While at it, I did a video.

 

you rock brother. thanks for sharing

 

you drained your coolant?why?

 

Had to pull the upper rad hose out of the way.

 

oh yea true. l didnt drain my coolant replacing my alternator. it was a pain though.

 

Feel free to post your failure mileage.

My alternator initially failed at 223,200. I installed a used one harvested from a junk yard which tested good at O'Rielly's and bad at AutoZone (I later learned that their machine was broken). A month later I had a starter fail and the alternator was showing low volts (10.9v to 11.2v) intermittent. So I pulled another alternator from another junk yard which tested bad. Went back and got another which tested good. So, at 223,850 I have another jy alternator with a 6 month warranty. This one is showing the highest volts since I have owned the car. Hopefully it will last a while.

 

Some good info here, thanks much!

I was checking out a few things on my recently purchased 97 850R wagon and noticed my alternator is putting out around 13.6 volts. I am used to seeing around 14.4 volts based on my other previous vehicles - this is my first Volvo.

Is 13.6 OK, or should I be expecting a higher voltage?

When considering all routes with an alternator replacement, my local parts stores get from $180-330 for a reman alternator, depending on what brand and warranty.

rockauto.com has alternators ranging from $120 with no core to $380 including the core.

The last alternator I had rebuilt was around $100, but that was nearly 10 years ago, and I had to go 25 miles out of town to find someone who rebuilt foreign alternators.

What does a salvage yard in your area charge for a used alternator? How do you know what years and models of Volvos you can search out to find an alternator that will work in the 850?

 

The problem with voltage is that if it's too low the alternator is bad. It's pretty safe to say if it's not at least 12.5 you likely have a bad alternator. Yes that's really low and for it to be good you'd need to be driving with everything on and everything on high including the three extra stereo amps. (I do indeed have three)

Voltage is just the "pressure" it's not the flow. Amps are what really matter and the amperage output is the important factor. A bad alternator can be charging at 14.4 volts and "look" OK on a voltmeter but it's only putting out a third of it's capacity due to a bad diode trio. If it's charging at 14.4 on my wagon and I have the headlights, heater blower, seat heaters and wipers on due to it being really cold and snowy the 33 amps my 100 amp rated bosch alternator is putting out will not be able to put anything into my battery and I'm running down the battery each minute.

A diode trio can break in three ways. It can fail and reduce the charging ability of the alternator to 66%, or to 33% or it can fail totally. The problem with an idiot light is the light only comes on if it's a total failure. If the alternator is charging a little, it fools the light and you get no warning. Well, other than unusually slow cranking if you're lucky.

Voltage is a test but it's not a very good one. If you're only at 13.6 and that's low to you (me too in general) take it to an auto parts store or two and see what they say. If you get two different opinions, take it to a third. They can put a hand held tester (free) on the battery and check the alternator under a load to see how many amps it's putting out. That's the true test you need to know.

But in the end you need both voltage to push and amperage flow to maintain a charge in your battery.
If your battery is charged and you don't have much on inside the car then 13.6 or 13.2 might be perfectly acceptable since the regulator isn't seeing a demand for much current and so doesn't need the "pressure" to push more amps. If however it's twenty below and it took forever cranking the beast to get it started and you're turned everything on it should try to climb close to 15 volts to push the most amps into the system it can.

 

I monitor my volts live with my OBD-II tool, ScanGauge II. I have never seen any of my FWD Volvo's show more than 13.7 volts. The wagon I now have has always shown 12.4 - 12.8v. Not saying that is good, just what it is.

The junk yard that I visit sells alternators for $25. Used batteries for the same. We picked up a 6 month old battery for the S70 a few months ago for $25. If you pull one from a junk yard have it tested by 2 parts outlets.

On another note, I may have a bad wire in my system, my volts are erratic. I'm working on it to figure it out.

 

Be careful