volts drop

pacman67 · Oct 3rd, 2013, 22:38

Started noticing that when slowing down headlights dim slightly then brighten back up. Ran the torque app on volts test tonight and found that volts drop momentarily to 12 then back up to 13.5. On tickover it's a steady 13.5, but rev and as engine returns back to idle volts drop to 12 then return to 13.5. Obviously an alternator issue of some kind and I seem to remember reading about the voltage regulator being an issue. Previous owner mentioned he'd had the alternator clutch changed.

Georgeandkira · Oct 4th, 2013, 14:00

Hello, It sounds like the alternator is able to do its job and that the "switching" to and from 13.5V is delayed. At the very least, it's not smooth. That does point to the regulator. Since the P.O. had the freewheel changed I'd suspect the alternator was getting on in years. Pull the alternator and have the whole thing checked out by a competent shop. Find a rebuilder near you. They may just have a swap-out waiting for you on a shelf.

Also, have any battery of any age at all load tested for condition. At the VERY LEAST charge it up out of the car.

Do this now as Winter is coming. Kira

pacman67 · Oct 4th, 2013, 20:33

Was wondering if I'd get away with a volt regulator as opposed to a full alternator swap out.

Rossi-fan · Oct 4th, 2013, 22:18

Had similar problems with my S60, lights flickering, dashboard display flickering and irregular rev behavior. Changed the alternator regulator and all cured. If I remember, it was £40, , ,or was it 60 ?

pacman67 · Oct 4th, 2013, 22:39

Quote:

Originally Posted by Rossi-fan

Had similar problems with my S60, lights flickering, dashboard display flickering and irregular rev behavior. Changed the alternator regulator and all cured. If I remember, it was £40, , ,or was it 60 ?

That's the sort of thing I read, was it a alternator removal or fitted in situ ?

Rossi-fan · Oct 5th, 2013, 08:15

Not sure, I believe a few other parts had to be moved out of the way so they could get at it properly.

volvo2 · Oct 5th, 2013, 08:16

You might want to consider changing the battery. I had the headlights dropping at idle for years. I replaced the battery with a good quality Bosch at a higher AH and the issue went away.

I confess I don't know why this happened as I would have thought the battery is not involved once the engine is running, nevertheless that is what happened.

Rossi-fan · Oct 5th, 2013, 08:36

Quote:

Originally Posted by volvo2

You might want to consider changing the battery. I had the headlights dropping at idle for years. I replaced the battery with a good quality Bosch at a higher AH and the issue went away.

I confess I don't know why this happened as I would have thought the battery is not involved once the engine is running, nevertheless that is what happened.

Yes change the battery by all means, but start with the cheaper options first, you can always get the battery checked.

pacman67 · Oct 5th, 2013, 11:36

Changed battery with one from my t4 to compare and gave it a charge first, problem still persists.

Georgeandkira · Oct 5th, 2013, 16:18

Hello, That's good. Now compare the work of changing the regulator while the alternator is still in the car with simply removing the alternator and checking it out in broad daylight (on a bench). If your alternator is old enough to have had its freewheel go bad then you should consider the high likelihood of the bearings being near the end of their lives. I was always told that when a car gets old, "don't patch". Kira

Oct 3rd, 2013, 22:38	#1
pacman67 VOC Member Last Online: Dec 6th, 2023 14:09 Join Date: Feb 2009 Location: Richmond N Yorks	volts drop Started noticing that when slowing down headlights dim slightly then brighten back up. Ran the torque app on volts test tonight and found that volts drop momentarily to 12 then back up to 13.5. On tickover it's a steady 13.5, but rev and as engine returns back to idle volts drop to 12 then return to 13.5. Obviously an alternator issue of some kind and I seem to remember reading about the voltage regulator being an issue. Previous owner mentioned he'd had the alternator clutch changed. __________________ Regards, pacman67 previously held: V40 TD & S40 2ltr P1,V40 P2 sport lux, V70 XC P1, XC70 P2, V70 D5 P2 and P3, V40 T4,V70R, C30 R Design. currently held: V70 P3 D5 SE LUX, XC90 MK2 Inscription Pro.

Oct 4th, 2013, 14:00	#2
Georgeandkira Premier Member Last Online: Today 13:23 Join Date: Feb 2009 Location: Hackensack	Hello, It sounds like the alternator is able to do its job and that the "switching" to and from 13.5V is delayed. At the very least, it's not smooth. That does point to the regulator. Since the P.O. had the freewheel changed I'd suspect the alternator was getting on in years. Pull the alternator and have the whole thing checked out by a competent shop. Find a rebuilder near you. They may just have a swap-out waiting for you on a shelf. Also, have any battery of any age at all load tested for condition. At the VERY LEAST charge it up out of the car. Do this now as Winter is coming. Kira Last edited by Georgeandkira; Oct 4th, 2013 at 14:00. Reason: Winter Warning

Oct 4th, 2013, 20:33	#3
pacman67 VOC Member Last Online: Dec 6th, 2023 14:09 Join Date: Feb 2009 Location: Richmond N Yorks	Was wondering if I'd get away with a volt regulator as opposed to a full alternator swap out. __________________ Regards, pacman67 previously held: V40 TD & S40 2ltr P1,V40 P2 sport lux, V70 XC P1, XC70 P2, V70 D5 P2 and P3, V40 T4,V70R, C30 R Design. currently held: V70 P3 D5 SE LUX, XC90 MK2 Inscription Pro.

Oct 5th, 2013, 11:36	#9
pacman67 VOC Member Last Online: Dec 6th, 2023 14:09 Join Date: Feb 2009 Location: Richmond N Yorks	Changed battery with one from my t4 to compare and gave it a charge first, problem still persists. __________________ Regards, pacman67 previously held: V40 TD & S40 2ltr P1,V40 P2 sport lux, V70 XC P1, XC70 P2, V70 D5 P2 and P3, V40 T4,V70R, C30 R Design. currently held: V70 P3 D5 SE LUX, XC90 MK2 Inscription Pro.

Oct 4th, 2013, 22:18	#4
Rossi-fan Premier Member Last Online: Feb 12th, 2023 10:07 Join Date: May 2009 Location: Durham	Had similar problems with my S60, lights flickering, dashboard display flickering and irregular rev behavior. Changed the alternator regulator and all cured. If I remember, it was £40, , ,or was it 60 ?

Oct 5th, 2013, 08:15	#6
Rossi-fan Premier Member Last Online: Feb 12th, 2023 10:07 Join Date: May 2009 Location: Durham	Not sure, I believe a few other parts had to be moved out of the way so they could get at it properly.

Oct 5th, 2013, 08:16	#7
volvo2 Master Member Last Online: Apr 25th, 2024 17:44 Join Date: Nov 2001 Location: Evesham	You might want to consider changing the battery. I had the headlights dropping at idle for years. I replaced the battery with a good quality Bosch at a higher AH and the issue went away. I confess I don't know why this happened as I would have thought the battery is not involved once the engine is running, nevertheless that is what happened.

Oct 5th, 2013, 16:18	#10
Georgeandkira Premier Member Last Online: Today 13:23 Join Date: Feb 2009 Location: Hackensack	Hello, That's good. Now compare the work of changing the regulator while the alternator is still in the car with simply removing the alternator and checking it out in broad daylight (on a bench). If your alternator is old enough to have had its freewheel go bad then you should consider the high likelihood of the bearings being near the end of their lives. I was always told that when a car gets old, "don't patch". Kira

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