Electrical R53 alternator/voltage regulator failing?
#1
R53 alternator/voltage regulator failing?
Lately when I place a load on the electrical system by running the A/C and radio, I can see a drop in voltage (I have the voltmeter installed) from 14V to 12V, sometimes as low as 10V. This occurs 100% of the time when engine RPM is below 3000; it occurs about 70% of the time at 3000RPM or above. It's getting to the point where I really can't turn on the A/C unless I am at highway speed.
My guess is that this is a failure of the voltage regulator, which I assume these days is integrated into the alternator, necessitating a replacement alternator. Any thoughts here? Suggested tests I can perform?
If I do have to replace the alternator, is there a source for a high-output model?
My guess is that this is a failure of the voltage regulator, which I assume these days is integrated into the alternator, necessitating a replacement alternator. Any thoughts here? Suggested tests I can perform?
If I do have to replace the alternator, is there a source for a high-output model?
#2
Lately when I place a load on the electrical system by running the A/C and radio, I can see a drop in voltage (I have the voltmeter installed) from 14V to 12V, sometimes as low as 10V. This occurs 100% of the time when engine RPM is below 3000; it occurs about 70% of the time at 3000RPM or above. It's getting to the point where I really can't turn on the A/C unless I am at highway speed.
My guess is that this is a failure of the voltage regulator, which I assume these days is integrated into the alternator, necessitating a replacement alternator. Any thoughts here? Suggested tests I can perform?
If I do have to replace the alternator, is there a source for a high-output model?
My guess is that this is a failure of the voltage regulator, which I assume these days is integrated into the alternator, necessitating a replacement alternator. Any thoughts here? Suggested tests I can perform?
If I do have to replace the alternator, is there a source for a high-output model?
Melanie
#6
How about the Crank Pulley? I keep forgetting this when Trouble Shooting the Charging System.. When the Crank Pulley starts to fail the outer ring slips on the inner and when under load from the Alternator and will not spin the Alternator fast enough.
EDIT: And of course if the crank pulley is fine, then more than likely your alternator is failing. Back in the day I used to rebuild them, well going back to Generators and Voltage Regulators, then in some cases even alternators, replacing brushes and even a diode or two. But now from a shop perspective, unless you are working on an item that is so rare you will either have to mortgage your house to afford the replacement part, or even the part just isn't available for replacement rebuilding a mass produced alternator just doesn't pay off. The OEM MINI compact Alternator generally sales for about $716.00 but can be found for as low as $278.00 or so and the OEM Voltage Regulator as a replacement part is around $122.00 but can be found for as low as $120.00. So it pays to just replace the assembly, do it once... and...
Best of luck.
Motor on!
EDIT: And of course if the crank pulley is fine, then more than likely your alternator is failing. Back in the day I used to rebuild them, well going back to Generators and Voltage Regulators, then in some cases even alternators, replacing brushes and even a diode or two. But now from a shop perspective, unless you are working on an item that is so rare you will either have to mortgage your house to afford the replacement part, or even the part just isn't available for replacement rebuilding a mass produced alternator just doesn't pay off. The OEM MINI compact Alternator generally sales for about $716.00 but can be found for as low as $278.00 or so and the OEM Voltage Regulator as a replacement part is around $122.00 but can be found for as low as $120.00. So it pays to just replace the assembly, do it once... and...
Best of luck.
Motor on!
Last edited by JABowders; 07-28-2015 at 03:52 AM.
#7
Anyone find a definitive answer to this issue? I am experiencing the exact same issue as the OP. 14.0 volts at Idle but drops to 12.3 and sometimes down to 11.8 when the AC is on. I only run the AC at highway speeds and even then it's only 13.5 volts. I know it's not the crank pulley because I replaced it with an ATI unit back in May.
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#8
Anyone find a definitive answer to this issue? I am experiencing the exact same issue as the OP. 14.0 volts at Idle but drops to 12.3 and sometimes down to 11.8 when the AC is on. I only run the AC at highway speeds and even then it's only 13.5 volts. I know it's not the crank pulley because I replaced it with an ATI unit back in May.
As an alternator ages/wears, the brushes wear...and the max output drops...
What you are seeing is 100% normal...IMO you are chasing a ghost (car hypochondriac?!, naww, just kidding!) Drive your car and enjoy it. When the alternator become MUCH weaker, you may need to replace it...but it sounds like it is doing fine.
Remember, an alternator output varies with rpm...and often much of its output might be going to the PS pump, recharging the battery, the cabin fan, radiator fan, lights, etc...most cars need the battery to even out the voltage since VERY few cars can run 100% of all loads possible solely off the alternator... No need too..the battery is a great storage device....the car just needs to handle the base loads...and the peak loads can get the extra boost from the battery...
The following users liked this post:
Chris W Rengert (07-05-2020)
#9
13.5 volts on the highway is fine....even with full load...
As an alternator ages/wears, the brushes wear...and the max output drops...
What you are seeing is 100% normal...IMO you are chasing a ghost (car hypochondriac?!, naww, just kidding!) Drive your car and enjoy it. When the alternator become MUCH weaker, you may need to replace it...but it sounds like it is doing fine.
Remember, an alternator output varies with rpm...and often much of its output might be going to the PS pump, recharging the battery, the cabin fan, radiator fan, lights, etc...most cars need the battery to even out the voltage since VERY few cars can run 100% of all loads possible solely off the alternator... No need too..the battery is a great storage device....the car just needs to handle the base loads...and the peak loads can get the extra boost from the battery...
As an alternator ages/wears, the brushes wear...and the max output drops...
What you are seeing is 100% normal...IMO you are chasing a ghost (car hypochondriac?!, naww, just kidding!) Drive your car and enjoy it. When the alternator become MUCH weaker, you may need to replace it...but it sounds like it is doing fine.
Remember, an alternator output varies with rpm...and often much of its output might be going to the PS pump, recharging the battery, the cabin fan, radiator fan, lights, etc...most cars need the battery to even out the voltage since VERY few cars can run 100% of all loads possible solely off the alternator... No need too..the battery is a great storage device....the car just needs to handle the base loads...and the peak loads can get the extra boost from the battery...
#10
See above EDIT:
I had a MINI Alternator die on me when driving, the first real signs I was in trouble was the voltmeter was dropping down below 12 volts, then on occasion it would just drop out to 0 volts and the dash would go wacky as the needles would bounce from extreme to extreme and every warning light would flash and the LCDs would go dark. But I had several hours of highway driving to go before I could stop, and since I had just enough power in the battery (I would end up replacing it as well) to keep the car running I was able to make it to my destination, when I turned off the car... that was it.
Replacing the Alternator can be a DIY job, should only take about 2.5 hours if you have the tools and have never done it before, but you have taken the front of the car off for other maintenance reasons.
I will add as yet another alternative to buying new, is buying a used unit from a Auto Recycle Center (Junk Yard, Breaker), you could possible find one for as low as $100.00 from a low mileage vehicle.
Best of luck.
Motor on!
I had a MINI Alternator die on me when driving, the first real signs I was in trouble was the voltmeter was dropping down below 12 volts, then on occasion it would just drop out to 0 volts and the dash would go wacky as the needles would bounce from extreme to extreme and every warning light would flash and the LCDs would go dark. But I had several hours of highway driving to go before I could stop, and since I had just enough power in the battery (I would end up replacing it as well) to keep the car running I was able to make it to my destination, when I turned off the car... that was it.
Replacing the Alternator can be a DIY job, should only take about 2.5 hours if you have the tools and have never done it before, but you have taken the front of the car off for other maintenance reasons.
I will add as yet another alternative to buying new, is buying a used unit from a Auto Recycle Center (Junk Yard, Breaker), you could possible find one for as low as $100.00 from a low mileage vehicle.
Best of luck.
Motor on!
#11
Here is a great DIY for the alternator. Check it out as it also provides a lot of great information about it and failures. Alternator options here too if needed.
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The following 2 users liked this post by PelicanParts.com:
Chris W Rengert (07-05-2020),
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