jschaefer7406 Posted October 12, 2010 Report Share Posted October 12, 2010 Hello all, Been having some starting issues lately with the Wife's '00 XC. Voltage drop tests indicate that the B+ cable is on it's way out, but the really bad readings are taken from the alternator-to-starter and starter-to-battery cables. Reading roughly 1 volt drop between alternator and battery. Voltage is good at the alternator post though, about 13.8v @ warm idle with loads. This brings me to my problem. Out of curiousity, I performed the same tests on my '00 S70 (even though I haven't been having any troubles with it). Found a little less drop (roughly .6-.7v between alternator and battery), but charging voltage at the alternator is low on mine. Only reading around 12.8v at the alternator post (again, all loads on and idling warm). Instinct tells me that a regulator will take care of it, as they were a common failure on the RWD models. Is this the case here, or should I consider replacing the entire unit? Any help is appreciated, Joe Link to comment Share on other sites More sharing options...
NEU Posted October 12, 2010 Report Share Posted October 12, 2010 When my alternator died I looked into replacing the regulator but couldn't find replacement part. I had done this with my old 245 but the new style I think you just have to get a rebuilt unit, which is what i did. Link to comment Share on other sites More sharing options...
Dave 54 Posted October 12, 2010 Report Share Posted October 12, 2010 Check around your area for a rebuild shop. I have one not more then 7 blocks from the house, drop it off in the am pick it up later that afternoon usually or next day. I believe per Volvo the cables should not exceed .5v drop, if they do it is recommended to replace them. You can buy the cable from McMasterCarr for cheap, get some tinned ends and solder slugs on ebay and make them for right around 30-40 bucks. there was a thread called the big 3 awhile ago that covered redoing the cables. Link to comment Share on other sites More sharing options...
--Aaron-- Posted October 12, 2010 Report Share Posted October 12, 2010 As Dave said I would replace the cables on both cars, you can DIY as mentioned or I can simply tell you that between the B+, alternator to starter and starter to alternator cables you are looking at roughly ~150 for Genuine parts. I know this. The alternator, Mike went with a rebuilt Bosch unit. It came, I installed it and the next day he calls freaking out that there's a horrible noise from that area. To make it known I did forget to tighten that one P/S pump brace bolt. (long sleeve on it) When we double checked things we found that the rebuilt alternator pulley was actually spaced out about 1/4 in. more than the other pulleys. A Genuine Volvo alternator runs around ~340 plus a core charge, personally, if you plan on keeping the car for a long time yet I'd go that route.......which I did. All up to you man, a rebuilt unit will do the job just fine. Some would say I just like to waste money. I'm a sucker for Genuine parts, Genuine typically means less headache. Link to comment Share on other sites More sharing options...
Ihatespeedbumps Posted October 12, 2010 Report Share Posted October 12, 2010 Voltage regulators will fix the majority of these poorly charging alternators, but you need to remove it and check the armature for excessive wear. A rebuild is usually the best long term option. Link to comment Share on other sites More sharing options...
jschaefer7406 Posted October 12, 2010 Author Report Share Posted October 12, 2010 Hello all, Thanks for the replies fellas. Yeah, I do plan to keep the S70 for a long while, so maybe I will look into a rebuild or OEM replacement alternator. Hate to risk a $90 regulator (available from Volvo BTW), being I cannot return it if it doesn't take care of it. As said, no real symptoms with the S70, just checked it out because I know they're somewhat prone to cable failure. Oddly enough the B+ cable in mine looks very clean yet and tests fine, just the .7v drop between the alternator and battery... She, on the other hand, is considering parting with the XC in the spring/summer. Luckily hers only need cables, but still a $180 investment . Hers cranks very long (tach bounces randomly also) and has a very black B+ terminal, so I figured I'd start there. Definitely cranks longer than a failed fuel pump check valve, so it must be elsewhere. Thanks for the info guys, Joe Link to comment Share on other sites More sharing options...
lookforjoe Posted October 14, 2010 Report Share Posted October 14, 2010 Old Volvos were easy - two screws & the regulator was out. Volvo even sold regulator brush kits, since that was typically what wore out anyway. Since even getting to the regulator involves removing the alternator, I'd just go with a reman alt. Personally, as long as it's a comparable Bosch unit, I'd use it. Volvo just adds a markup to it. Link to comment Share on other sites More sharing options...
NEU Posted October 15, 2010 Report Share Posted October 15, 2010 Old Volvos were easy - two screws & the regulator was out. Volvo even sold regulator brush kits, since that was typically what wore out anyway. Nice thing about the old Volvo alts were you could use any voltage regulator from any Bosch alt. I rebuilt my Volvo alt new brushes and brush holder for my '71 Mercedes, that was the same as my dad '84 BMW, and the same as my '70 Porsche. I also use an external adjustable voltage regulator to increase the output to 14.5 at idle. That internal regulator would barely make 12v when it got hot. I wish we could do the same for the newer alts. Link to comment Share on other sites More sharing options...
Keaton85 Posted October 15, 2010 Report Share Posted October 15, 2010 I'm a sucker for Genuine parts, Genuine typically means less headache. haha yeah, idono how you afford all the parts! I am more on the other side of the fence... Anyway, I would go aftermarket with alt. or have a starter shop rebuild it for cheap. Not much to these things really... I can't imagine Volvo (Bosch) doing anything different then any other rebuild. Link to comment Share on other sites More sharing options...
lookforjoe Posted October 15, 2010 Report Share Posted October 15, 2010 Nice thing about the old Volvo alts were you could use any voltage regulator from any Bosch alt. I rebuilt my Volvo alt new brushes and brush holder for my '71 Mercedes, that was the same as my dad '84 BMW, and the same as my '70 Porsche. I also use an external adjustable voltage regulator to increase the output to 14.5 at idle. That internal regulator would barely make 12v when it got hot. I wish we could do the same for the newer alts. Where did you get the adjustable v/reg? I could use one on my X1/9 (same Bosch setup as 200/700), that barely puts out 13v @ idle with lights, fan etc. Especially when hot - it's right next to the exhaust header Link to comment Share on other sites More sharing options...
NEU Posted October 15, 2010 Report Share Posted October 15, 2010 Where did you get the adjustable v/reg? I could use one on my X1/9 (same Bosch setup as 200/700), that barely puts out 13v @ idle with lights, fan etc. Especially when hot - it's right next to the exhaust header I can't remember who sold them, they had a kit or just the reg. I had my dad check the he's got one on his gray market '84 735i. Companies name is Transpo, they make alt part. Problem is the brush holder and a 2 connector plugs. I used my old MB brush holder and got the plugs off of 2 an old '60 and '70's BMW and MB w/external regs. If you found one of those you could get the brush holder and the plugs from it and replace the brushes. Then once you install everything adjust it using a volt meter. At idle it should be 14.5v. Link to comment Share on other sites More sharing options...
jschaefer7406 Posted March 11, 2011 Author Report Share Posted March 11, 2011 Hello all, Sorry to revive this old thread, just wanted to confirm my voltage readings were cause for alarm before buying an alternator. Ordered one at the dealer, gonna be up that way tomorrow. Hoping to hear back from some of the experts here before then . I assume normal charging voltage on these should be 14-14.4V @ idle, like most other cars? The S70 exhibits no symptoms, even started right away when it was 1°F here a few weeks back. Battery voltage after sitting overnight is around 12.3 though, which I know is low. Unable to confirm the dip into the 12's (with loads, idling) that's I had in October (nonstop rain here lately, been unable to retest ). Anyway, I guess I'm just looking to see if alternator failure on these is normal. I have 143k miles on her now. Don't mind replacing if they all go eventually, especially if these readings do sound bad. Hasn't ever really given me any problems though, so I'm not sure what to do :confused:. Thoughts? Thanks, Joe Link to comment Share on other sites More sharing options...
--Aaron-- Posted March 11, 2011 Report Share Posted March 11, 2011 After I installed my new alternator it's output voltage read at 14.4. As far as I know a properly charged battery will be at ~12.75 after allowing some time to sit. Is the .45 difference a major issue? That I do not know. I can tell you that alternator failures aren't too common around here, more often than not it's the cables. Link to comment Share on other sites More sharing options...
jschaefer7406 Posted March 11, 2011 Author Report Share Posted March 11, 2011 Aaron, Thanks for the reply. I do know that .45v is a huge amount for a battery. Heck, 12.6 is fully charged, and 12.3 is only around 1/2 charged. Doesn't seem right that so little voltage determines 0 to full charge, but that I do know . What I wasn't sure of is, whether it is low because of the cables or alternator. I have the alt-starter cable on hand. Going to pick up the starter-battery cable tomorrow. Didn't order the B+ cable, as mine tests perfect and the terminal and such is shiny. Not sure if it was previously replaced or what, but seems okay for now. Battery is only a year old BTW... In any case, I did my best to probe the alternator terminal itself (as you know, kinda hard with the fan and such in the way). Probing there was when I read 12.8v in October. As said, have wanted to confirm, bit the weathers been uncooperative . Thanks, Joe Link to comment Share on other sites More sharing options...
--Aaron-- Posted March 11, 2011 Report Share Posted March 11, 2011 Wow, hard to believe that little bit of voltage makes such a difference, I mean .45? Less than half a volt? In my opinion 12.8 isn't all that bad, especially with full load on the electrical system. I'm curious as to what reading you get at the alternator while idling with no additional load...... I think if I were you I would change the cables you have on hand for good measure and leave the alternator alone for the time being. I would wait until with full load the alternator is showing closer to 12V output to overhaul it. You'll still be able to drive and such if it dips down that low. When my voltage battle began mine was putting out about 11.4 with full load, even with that low of an output the only thing I noticed was dim interior lights. All my exterior lighting and such wasn't being affected yet. If your battery is only a year old and is already showing discharge I would take it back and have it taken care of under warranty. I'm pretty sure it would be a free exchange. Link to comment Share on other sites More sharing options...
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