Not a mechanic or techie, so please correct any mistakes in the following.
Westies have a Bosch 200 amp alternator.
I wonder if this Bosch alternator is designed for continuous duty use and if our Westies put a heavy burden on the alternator from recharging coach batteries and running the rooftop air conditioner.
It seems like Westy owners are having to replace the alternator or voltage regulator at relatively low mileage.
There are three issues to watch: corrosion from road spray, voltage regulator, and pulley.
1. Corrosion (Colorado folks, etc.)
LindenEngineering posted that road spray from certain states with snow chemicals can create corrosion and alternator problems. Fix is to clean.
https://sprinter-source.com/forum/showpost.php?p=172998&postcount=11
https://sprinter-source.com/forum/showpost.php?p=185945&postcount=6
2. Voltage Regulator
The voltage regulator is a screwed-in plug-in part at the back of the alternator. It has brushes (rectangular metal prongs like an electrical plug) which contact a spinning cylinder. Over time, the brushes wear down so the alternator does not provide consistent voltage.
Often, it is the voltage regulator which is the issue and not the rest of the alternator. As the regulator is about $60-90 compared to a new alternator of $350 to $900, may be worthwhile to replace the voltage regulator.
No obvious test to see whether voltage regulator or rest of alternator is at issue, but if alternator looks clean on outside (no scorch marks) and no issue with pulley (see below), then low and/or fluctuating voltage readings maybe a faulty voltage regulator.
(Assume one has checked all cable connections and cables before looking at voltage regulator.)
Our central computer console shows voltage at coach batteries which may be a sufficient proxy for reading alternator voltage output when engine is running (no solar panels).
TFrazie did extensive research to find the correct part number. Follow-up poster confirmed Tim's info in the first thread below.
https://sprinter-source.com/forum/showthread.php?t=56836&highlight=Alternator
https://sprinter-source.com/forum/showpost.php?p=169369&postcount=4
3. Pulley
At the front of the alternator is a special clutch type pulley. These pulleys often fail before the alternator fails.
A worn or defective pulley will often cause the serpentine belt to flutter and can wear out the tensioner (often causing various pulleys and/or serpentine belt to break).
A. Inspect the serpentine belt for flutter when engine is running.
B. When engine is turned off, listen for any funny noises for a few seconds after turning off engine (defective alternator pulley often makes noise).
C. Visually look at alternator pulley for proper alignment with rest of serpentine belt components.
D. Remove serpentine belt. [Following needs to be confirmed/corrected.]
1. Rotate and spin alternator pulley clockwise. Should be smooth rotation (but not freely spin?). Inside alternator fins should also move.
2. Rotate alternator pulley counterclockwise???
3. Stick a plastic pen through an opening at front of alternator and between the fins so fins can't move. Then try to rotate alternator pulley clockwise. Pulley should be locked and not rotate.
4. Stick a pen like #3 above, and rotate pulley counterclockwise. Pulley should rotate counterclockwise (but not freely spin?).
If have a pulley problem, can replace pulley. Will need special tools, available from Europarts-SD.com
As the price of the pulley and tools may approach half the price of a new alternator, some folks just buy a new alternator.
https://sprinter-source.com/forum/showthread.php?t=13893&highlight=Magnesium
4. Replacement Alternator
By buying the Bosch 200 amp alternator, you can save a lot of money versus buying the 200 amp alternator from Dodge or Mercedes.
Discus located the Bosch AL0817N as the correct 200 amp replacement for our Westies. The Bosch replacement has the pulley and the voltage regulator as part of the alternator.
Discus and Juju purchased from Amazon.
Europarts-sd.com also carries but at a higher price.
Eurocampers.com sells rebuilt ones at an even higher price.
https://sprinter-source.com/forum/showthread.php?t=26087&highlight=Alternator+pulley
https://sprinter-source.com/forum/showthread.php?t=18432
Westies have a Bosch 200 amp alternator.
I wonder if this Bosch alternator is designed for continuous duty use and if our Westies put a heavy burden on the alternator from recharging coach batteries and running the rooftop air conditioner.
It seems like Westy owners are having to replace the alternator or voltage regulator at relatively low mileage.
There are three issues to watch: corrosion from road spray, voltage regulator, and pulley.
1. Corrosion (Colorado folks, etc.)
LindenEngineering posted that road spray from certain states with snow chemicals can create corrosion and alternator problems. Fix is to clean.
https://sprinter-source.com/forum/showpost.php?p=172998&postcount=11
https://sprinter-source.com/forum/showpost.php?p=185945&postcount=6
2. Voltage Regulator
The voltage regulator is a screwed-in plug-in part at the back of the alternator. It has brushes (rectangular metal prongs like an electrical plug) which contact a spinning cylinder. Over time, the brushes wear down so the alternator does not provide consistent voltage.
Often, it is the voltage regulator which is the issue and not the rest of the alternator. As the regulator is about $60-90 compared to a new alternator of $350 to $900, may be worthwhile to replace the voltage regulator.
No obvious test to see whether voltage regulator or rest of alternator is at issue, but if alternator looks clean on outside (no scorch marks) and no issue with pulley (see below), then low and/or fluctuating voltage readings maybe a faulty voltage regulator.
(Assume one has checked all cable connections and cables before looking at voltage regulator.)
Our central computer console shows voltage at coach batteries which may be a sufficient proxy for reading alternator voltage output when engine is running (no solar panels).
TFrazie did extensive research to find the correct part number. Follow-up poster confirmed Tim's info in the first thread below.
https://sprinter-source.com/forum/showthread.php?t=56836&highlight=Alternator
https://sprinter-source.com/forum/showpost.php?p=169369&postcount=4
3. Pulley
At the front of the alternator is a special clutch type pulley. These pulleys often fail before the alternator fails.
A worn or defective pulley will often cause the serpentine belt to flutter and can wear out the tensioner (often causing various pulleys and/or serpentine belt to break).
A. Inspect the serpentine belt for flutter when engine is running.
B. When engine is turned off, listen for any funny noises for a few seconds after turning off engine (defective alternator pulley often makes noise).
C. Visually look at alternator pulley for proper alignment with rest of serpentine belt components.
D. Remove serpentine belt. [Following needs to be confirmed/corrected.]
1. Rotate and spin alternator pulley clockwise. Should be smooth rotation (but not freely spin?). Inside alternator fins should also move.
2. Rotate alternator pulley counterclockwise???
3. Stick a plastic pen through an opening at front of alternator and between the fins so fins can't move. Then try to rotate alternator pulley clockwise. Pulley should be locked and not rotate.
4. Stick a pen like #3 above, and rotate pulley counterclockwise. Pulley should rotate counterclockwise (but not freely spin?).
If have a pulley problem, can replace pulley. Will need special tools, available from Europarts-SD.com
As the price of the pulley and tools may approach half the price of a new alternator, some folks just buy a new alternator.
https://sprinter-source.com/forum/showthread.php?t=13893&highlight=Magnesium
4. Replacement Alternator
By buying the Bosch 200 amp alternator, you can save a lot of money versus buying the 200 amp alternator from Dodge or Mercedes.
Discus located the Bosch AL0817N as the correct 200 amp replacement for our Westies. The Bosch replacement has the pulley and the voltage regulator as part of the alternator.
Discus and Juju purchased from Amazon.
Europarts-sd.com also carries but at a higher price.
Eurocampers.com sells rebuilt ones at an even higher price.
https://sprinter-source.com/forum/showthread.php?t=26087&highlight=Alternator+pulley
https://sprinter-source.com/forum/showthread.php?t=18432
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