Maintenance/Repair: Alternator

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

Update (info based on new Bosch AL0817N 200 amp alternator):

3. Pulley

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.

[Yes, correct. Pulley can be hand-turned/rotated smoothly clockwise and counterclockwise. Does not spin by itself more than a quarter turn or so. Internal fins/vanes also move directly with pulley.]

2. Rotate alternator pulley counterclockwise???

[Yes. Pulley can be hand-turned/rotated smoothly counterclockwise. The internal alternator fins/vanes also move directly.]

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.

[Yes, correct. When pen is stuck so fins cannot move, the pulley also cannot be hand-turned/rotated CLOCKWISE.]

4. Stick a pen like #3 above, and rotate pulley counterclockwise. Pulley should rotate counterclockwise (but not freely spin?).

[Pulley does NOT hand-turn/rotate smoothly counterclockwise when fins/vans "locked," but hand-turns/rotates like one is unscrewing the pulley--although not really unscrewing.]

4. Replacement Alternator

Regulator or Alternator: :Should you get one or carry a spare regulator?

Several Westy owners have had alternator issues which were fixed by replacing the regulator. The regulator is screwed into the alternator.

Other Westy owners have replaced their alternator around the 100,000 mile mark or so. Not clear whether a pulley and/or regulator issue.

In lieu of replacing prematurely or hauling a spare alternator around, Europarts-SD.com is good at emergency shipments.

Lifecycle:

I believe OneManVan noted in another thread that a cable bolt between the alternator and battery--Kerstner air conditioner (not sure) was very hot when running the Kerstner air conditioner off the engine alternator.

Besides the Kerstner air conditioner, the Bosch alternator also recharges the coach batteries.

So there is little info as to how the Bosch alternator is designed for continuous use in running Kerstner air conditioner and recharging the coach batteries. It'd be interesting to know whether replaced regulators and/or alternators occur more frequently with owners who often use the Kerstner off the engine alternator.and who often boondock or dry-camp without hookups or solar.

But, it seems several Westy owners have replaced alternator (or regulator) without a lot of miles (100,000 or so?).

Amazon:

I purchased this new alternator from Amazon Direct and Fulfilled by Amazon, like Discus and JuJu did, as Amazon had a good price.

But, be wary of the lack of protective packaging.

I originally purchased one from Amazon a year or so ago as a spare. Unfortunately, the integral black plastic cover was chipped and cracked and I was concerned that the alternator may have been dropped in transit (so possibly unseen damage internally). So I returned.

So a year or so later, ordered a new alternator from Amazon. Right before the delivery date, the shipper returned it to Amazon as damaged in transit.

So Amazon shipped out a replacement--the new one I currently have.

It comes without any protective packaging (just some cardboard wrap inside and the Bosch retail box). There is a small hairline crack in the integral black plastic cover.

Installation.

Search the T1N Write-Up subforum for excellent threads on installation.

One thing the threads highlight is the importance of installing the alternator in the right position or dire consequences.

While obvious that the alternator pulley is in front, the alternator can be rotated and bolted on in the wrong position. So need to watch the shape of the alternator and which position to install.

In the T1N subforum, a poster provided an explanation of the alternator pulley clutch operation. Poster also provided another test of proper operation.

https://sprinter-source.com/forum/showthread.php?t=63609

(Additional test)

3. Pulley
D. Remove Serpentine Belt
5.

While holding onto pulley, give a quick twist of the pulley clockwise. You should feel/see the internal alternator fins continue to move slightly after quick twist is made.

In the counterclockwise direction, a quick twist will feel different--the internal alternator fins will stay in position with the pulley so no continued movement.

Your hand feels less of an impact with a clockwise quick twist versus a counterclockwise quick twist.

I ordered this 150 amp Bosch alternator from Amazon after cross checking part numbers several times. Mine is a base 2006 2500 Freightliner so I don't need the extra 50 amps and this one is the same price as the (assumed) 90 amp.
Hope it fits
https://www.amazon.com/gp/product/B000BZII30/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Per the reviews on it apparently the regulator is an included unit. My problem was with overvoltage from the regulator affecting of all things the transmission shifting.
Who knew ?

Just looking for some clarification.

Seems the OEM alternator has a clutch that can be tested by spinning the pulley.

However, the description of the same tests on the Bosch AL0817N seems to contradict those same tests:

"[Yes, correct. Pulley can be hand-turned/rotated smoothly clockwise and counterclockwise. Does not spin by itself more than a quarter turn or so. Internal fins/vanes also move directly with pulley.]

[Yes. Pulley can be hand-turned/rotated smoothly counterclockwise. The internal alternator fins/vanes also move directly.]"


My understanding is the fins should only turn when rotated clockwise, otherwise it indicates a bad clutch.

So, if the Bosch AL0817N rotates the fins when turned counterclockwise, this implies the same clutch mechanism is not present, and based on reading, would cause wear on the tensioner and belts.....

Any comments? Am I missing something?

Also, to quote Europarts "To check the integrity of your alternator pulley, simply remove the belt and place a screwdriver into the front of the alternator cooling fan to stop the armature from rotating. Then turn the pulley by hand. If it moves one direction but, not the other, it is functional. If it will not rotate at all, it has failed."

Maybe the Bosch AL0817N is the correct alternator, but does not have the correct pulley installed?

All tests withOUT serpentine belt. Three tests.

1. Rotating the pulley by hand in either direction, and the alternator vanes also turn smoothly in conjunction.

2. (Wear gloves) Spin the pulley clockwise really fast, then hold the pulley to a full stop. The alternator vanes continue rotating (maybe an inch as I can't spin pulley that much).

Do the same counterclockwise, but the alternator vanes do NOT continue rotating when you hold pulley to full stop.

This is probably the test for clutch mechanism. But hard to spin pulley fast enough for a quick hand stop.to see if alternator.vanes continue rotating in one direction.

3..Stick a pen inside the alternator vanes so they canNOT move in either direction. Pulley cannot rotate clockwise. You can rotate pulley counterclockwise but it's like unscrewing something. (Europarts-SD didn't seem to indicate how easily pulley should move and in wjat direction?)

As Discus, Juju, and I believe others have used this alternator without an issue, it should be the right alternator with right pulley.

As I have not needed to replace alternator yet, my new one is still unused in the box. It could be that the new alternator in.the box is defective given the above test results, but they seem consistenr with what others are saying. Check out the link in post 5 where the pulley and alternator vanes move in either direction, but the alternator vanes only continue moving forward in one direction with hand stop of the pulley when spinning fast.

Note: By the way, never did get good info on how to tell whether regulator is bad versus alternator is bad. Also, am not a mechanic or techie, and DIY only if supervised or paint by numbers.

Please post whatever you find. Thanks.

The regulator assembly also includes the brushes, so that makes it an integral part of the "alternator" system instead of only being a separate regulator.

--dick

Thanks OldWest.

I guess the ones that confuse me are:

"Rotating the pulley by hand in either direction, and the alternator vanes also turn smoothly in conjunction."

I assumed based on other tests that the vanes would only turn when rotated clockwise. When turned counterclockwise, the vanes would not turn. Perhaps this is an incorrect assumption on my part.

This was stated from another thread, which seems to contradict what you wrote, but maybe I am misinterpreting something, or the clutch only comes into play once the vanes are moving.

"With the belt off, grab the alternator pulley and spin the pulley both ways rapidly back and forth... you won't need much of a turn. perhaps only even a quarter turn each way. It should only spin the internals in one direction. If you feel yourself spinning the internals up and down both ways, the alternator clutch is seized. "


And your third test:

"3..Stick a pen inside the alternator vanes so they canNOT move in either direction. Pulley cannot rotate clockwise. You can rotate pulley counterclockwise but it's like unscrewing something. (Europarts-SD didn't seem to indicate how easily pulley should move and in wjat direction?)"

I assume that with the pen inserted, it will NOT turn clockwise (as stated), but would turn counterclockwise, but fairly easy I would think. But maybe what you are feeling is in fact normal and indicates the clutch mechanism is fine.


Was just doing a bunch of research on things, and wanted to try to clarify the differences I saw. Maybe the test I quoted above will shed some light on things.....

I am going to replace my belt this weekend, and was trying to get the "tests" correct so I can make sure all is OK while the belt is off. I will certainly post what I find. Nice you have one in a box to play with!

Will be interesting to see what you find.

I'm just describing what the new-in-box alternator acts like while also trying out the suggested tests. Have not checked the original installed alternator.

The quote you have seems to suggest my new, still in box alternator may be defective. Unless the word "spin" means the alternator vanes continuing at a different speed than pulley versus rotating.

Try moving the pulley slowly in each direction. Then try moving fast in one direction, with a sudden stop. Then try other direction. Then do a back and forth moving fast in both directions? Then with pen stuck in vanes.

Hard to describe feel of pulley. Smooth easy rotation but heavy (need to use muscle, not just fingertips). Unscrewing top of jar?

While under the van, also check the harmonic balancer. Guess you're supposed to look visually for any cracks. Also, you could pull the pulley back and forth to see if any movement.

Also check the pulleys. New idler pulleys rotate smoothly and don't spin very much by themselves once you stop spinng them. Old pulleys continue to spin and sound like the wheels on toy cars.

Never checked (forgot to) how the air conditioning pulley feels like when changed idler pulleys and serpentine belt awhile ago.

My alternator pulley clutch seems to be seized/broken. When I try to stop the pulley, it stops the internals as well. And when locked with a screwdriver, I cannot turn the pulley in either direction.

I am trying to find out if the pulley can be replaced without removing the alternator. If so, I will just do that. If the alternator needs to be removed anyway, I will replace the entire alternator.

If you do buy a new alternator, compare both the old and new side by side with all the various tests. It's difficult to describe.

Also, you might save your old alternator. There were some posts on folks getting their alternator rebuilt for cheaper than a new one. So you could keep an emergency one.

Europarts-sd.com has a new pulley for about $60, the pulley kit for about $32, and a voltage regulator for $80.

Amazon has a new Bosch 200 amp one for $312.

So you'll save a bunch of money if the only thing wrong is the pulley.

If you end up pulling tne alternator (or even if you don't), might remove the voltage regulator to see what it looks like. They call them brushes but they apparently look more like prongs on a plug.

We replaced our alternator with the one named above.

The pulley in our old alternator was bad. The new alternator behaves as OldWest described, and as it should.

We do not have room to store a spare alternator, so if someone wants our old one (with bad pulley, alternator is fine), make me an offer. It has about 65k miles on it.

Hmm, wish I read this post before I had my alternator replaced (bad bearings). My mechanic said 90 amp is standard for the Sprinter but what he pulled out of mine was a 150 amp, an upgrade over stock. I just replaced it with same (Bosch 150 amp) - the 200 was much more expensive and had several days lead time for delivery. So wondering if the 150 is sufficient - then again, the previous owner of my Westy had his for years, so guessing it must have performed adequately. Other than the bad bearings, I didn't notice any charging issues during my first month of ownership before replacing it. That's my only reference point, however.

The Amazon price mentioned by OldWest for the 200 is about what I paid for the 150 (maybe even a little less), and the price my mechanic quoted for it was over $500. Oh well.

If you have the original 12v Kerstner air conditioner on the roof and want to use it when driving, then the 150 amp alternator may not be enough. Even the 200 amp alternator may have problems starting and running the Kerstner air conditioner when the coach batteries are depleted (theory being too much load on the 200 amp alternator from air conditioner and recharging batteries).

If you are not planning to use Kerstner air conditioner when driving, the 150 amp alternator may be plenty.

Note that OneManVan found some terminal or wire on the 200 amp alternator really heated up when Kerstner air conditioner was used off engine.

Also, no info as to.whether the 200 amp Bosch alternator was designed for continuous load of an air conditioner.

Also note that Sprinters with Sprinter factory rooftop air conditioners seemed to have more issues with the harmonic balancer (probably from extra belt?).

How many miles on your Westy (on each alternator)? Three alternators sounds like a lot (presumably original 200 amp, 150 amp, and another 150 amp). But the Westy may have spent life in Colorado, and as Dennis/LindenEngineeering pointed out, Colorado is touch on alternators.

Note: The MSRP and selling prices of these Bosch alternators can really vary. Good source Europarts-sd.com has the 150 amp for.about $300.and the 200 amp for about $500.

https://europarts-sd.com/alternators.asp

Another good company, Eurocampers.com, has a new 200 amp one for $372 and a higher price of $440.for a rebuilt one (and the rebuilt price used to be higher). Eurocampers used to only have rebuilt ones.

http://www.eurocampers.com/2001--2006-Sprinter-Electrical--Charging-Starting_c_173.html

So thanks to Discus for figuring out model and others who found and used Amazon.

OldWest said:

If you have the original 12v Kerstner air conditioner on the roof and want to use it when driving, then the 150 amp alternator may not be enough. Even the 200 amp alternator may have problems starting and running the Kerstner air conditioner when the coach batteries are depleted (theory being too much load on the 200 amp alternator from air conditioner and recharging batteries).

If you are not planning to use Kerstner air conditioner when driving, the 150 amp alternator may be plenty.

...

How many miles on your Westy (on each alternator)? Three alternators sounds like a lot (presumably original 200 amp, 150 amp, and another 150 amp). But the Westy may have spent life in Colorado, and as Dennis/LindenEngineeering pointed out, Colorado is touch on alternators.
...

Click to expand...

The AC has been deleted which sounds like a good thing - makes room for a solar panel and lightens the roof load. Glad to hear the 150 will be fine. I will at some point add an inverter (1000 watt at least) but other than that, no significant loads.

My Westy originated in FL, then made its way to CA until '14 at which point it moved to CO. Its got about 42k miles on it.

I paid $307 from Newparts.com for the 200A. They have very good prices on lots of parts.

1. 150 Amp Was Enough in a DIY Conversion with Electric Kitchen and 4 House Batteries

https://sprinter-source.com/forum/showpost.php?p=262377&postcount=7

https://sprinter-source.com/forum/showpost.php?p=249324&postcount=8

2..42k Miles and 3 Alternators

Something sounds weird for that many alternators for such low mileage.

OldWest said:

1. 150 Amp Was Enough in a DIY Conversion with Electric Kitchen and 4 House Batteries

https://sprinter-source.com/forum/showpost.php?p=262377&postcount=7

https://sprinter-source.com/forum/showpost.php?p=249324&postcount=8

2..42k Miles and 3 Alternators

Something sounds weird for that many alternators for such low mileage.

Click to expand...

Who knows what happened with the first alternator. With the second, could have been a random manufacturing defect or something (sourced from Auto Zone according to records), although the alternator is probably not located in the most ideal spot being at the bottom where its more exposed to the elements. I've never had an alternator's bearings go bad before so I find that a bit unusual.